From b49faeb5eca8257899e089f1200799fc68e0a335 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Thu, 20 Apr 2017 11:35:51 +0200
Subject: [PATCH 1/9] Add bot ability to get issue comments

---
 .../dotty/tools/bot/PullRequestService.scala  | 24 +++++++++++++------
 bot/src/dotty/tools/bot/model/Github.scala    |  2 ++
 bot/test/PRServiceTests.scala                 | 15 ++++++++++++
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index 5ae0b37d0411..4b521c84a6eb 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -63,14 +63,17 @@ trait PullRequestService {
   def statusUrl(sha: String): String =
     s"https://api.github.com/repos/lampepfl/dotty/statuses/$sha"
 
+  def issueCommentsUrl(issueNbr: Int): String =
+    s"https://api.github.com/repos/lampepfl/dotty/issues/$issueNbr/comments"
+
   def toUri(url: String): Task[Uri] =
     Uri.fromString(url).fold(Task.fail, Task.now)
 
-  def getRequest(endpoint: Uri): Request =
-    Request(uri = endpoint, method = Method.GET).putHeaders(authHeader)
+  def getRequest(endpoint: Uri): Task[Request] =
+    Request(uri = endpoint, method = Method.GET).putHeaders(authHeader).pure[Task]
 
-  def postRequest(endpoint: Uri): Request =
-    Request(uri = endpoint, method = Method.POST).putHeaders(authHeader)
+  def postRequest(endpoint: Uri): Task[Request] =
+    Request(uri = endpoint, method = Method.POST).putHeaders(authHeader).pure[Task]
 
   def shutdownClient(client: Client): Unit =
     client.shutdownNow()
@@ -89,7 +92,7 @@ trait PullRequestService {
     def checkUser(user: String): Task[Commit => CommitStatus] = {
       val claStatus = for {
         endpoint <- toUri(claUrl(user))
-        claReq   <- getRequest(endpoint).pure[Task]
+        claReq   <- getRequest(endpoint)
         claRes   <- httpClient.expect(claReq)(jsonOf[CLASignature])
       } yield { (commit: Commit) =>
         if (claRes.signed) Valid(user, commit)
@@ -133,7 +136,7 @@ trait PullRequestService {
 
       for {
         endpoint <- toUri(statusUrl(cm.commit.sha))
-        req      <- postRequest(endpoint).withBody(stat.asJson).pure[Task]
+        req      <- postRequest(endpoint).withBody(stat.asJson)
         res      <- httpClient.expect(req)(jsonOf[StatusResponse])
       } yield res
     }
@@ -158,7 +161,7 @@ trait PullRequestService {
     def makeRequest(url: String): Task[List[Commit]] =
       for {
         endpoint <- toUri(url)
-        req <- getRequest(endpoint).pure[Task]
+        req <- getRequest(endpoint)
         res <- httpClient.fetch(req){ res =>
           val link = CaseInsensitiveString("Link")
           val next = findNext(res.headers.get(link)).map(makeRequest).getOrElse(Task.now(Nil))
@@ -170,6 +173,13 @@ trait PullRequestService {
     makeRequest(commitsUrl(issueNbr))
   }
 
+  def getComments(issueNbr: Int, httpClient: Client): Task[List[Comment]] =
+    for {
+      endpoint <- toUri(issueCommentsUrl(issueNbr))
+      req      <- getRequest(endpoint)
+      res      <- httpClient.expect(req)(jsonOf[List[Comment]])
+    } yield res
+
   def checkPullRequest(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
 
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index fafa2b86a37a..e3814deb47a1 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -40,4 +40,6 @@ object Github {
     id: Long,
     state: String
   )
+
+  case class Comment(user: Author)
 }
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index 08155d59dfd9..2858b42c73fe 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -10,12 +10,20 @@ import io.circe.parser.decode
 
 import model.Github._
 import org.http4s.client.blaze._
+import org.http4s.client.Client
 import scalaz.concurrent.Task
 
 class PRServiceTests extends PullRequestService {
   val user = sys.env("USER")
   val token = sys.env("TOKEN")
 
+  private def withClient[A](f: Client => Task[A]): A = {
+    val httpClient = PooledHttp1Client()
+    val ret = f(httpClient).run
+    httpClient.shutdownNow()
+    ret
+  }
+
   def getResource(r: String): String =
     Option(getClass.getResourceAsStream(r)).map(scala.io.Source.fromInputStream)
       .map(_.mkString)
@@ -60,6 +68,13 @@ class PRServiceTests extends PullRequestService {
     )
   }
 
+  @Test def canGetComments = {
+    val comments: List[Comment] = withClient(c => getComments(2136, c))
+
+    assert(comments.find(_.user.login == Some("odersky")).isDefined,
+           "Could not find Martin's comment on PR 2136")
+  }
+
   @Test def canCheckCLA = {
     val httpClient = PooledHttp1Client()
     val validUserCommit = Commit("sha-here", Author(Some("felixmulder")), Author(Some("felixmulder")), CommitInfo(""))

From e6ca06ac63283004380ca3d4910f634f950d5490 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Thu, 20 Apr 2017 14:53:21 +0200
Subject: [PATCH 2/9] Change to approving only latest commit, stub methods

---
 .../dotty/tools/bot/PullRequestService.scala  | 137 +++++++++++++-----
 bot/src/dotty/tools/bot/model/Github.scala    |   2 +
 2 files changed, 103 insertions(+), 36 deletions(-)

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index 4b521c84a6eb..4fa7d1d21881 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -75,17 +75,18 @@ trait PullRequestService {
   def postRequest(endpoint: Uri): Task[Request] =
     Request(uri = endpoint, method = Method.POST).putHeaders(authHeader).pure[Task]
 
-  def shutdownClient(client: Client): Unit =
-    client.shutdownNow()
+  def shutdownClient(client: Client): Task[Unit] =
+    client.shutdownNow().pure[Task]
 
   sealed trait CommitStatus {
     def commit: Commit
     def isValid: Boolean
   }
-  final case class Valid(user: String, commit: Commit) extends CommitStatus { def isValid = true }
+  final case class Valid(user: Option[String], commit: Commit) extends CommitStatus { def isValid = true }
   final case class Invalid(user: String, commit: Commit) extends CommitStatus { def isValid = false }
   final case class CLAServiceDown(user: String, commit: Commit) extends CommitStatus { def isValid = false }
   final case class MissingUser(commit: Commit) extends CommitStatus { def isValid = false }
+  final case class InvalidPrevious(users: List[String], commit: Commit) extends CommitStatus { def isValid = false }
 
   /** Partitions invalid and valid commits */
   def checkCLA(xs: List[Commit], httpClient: Client): Task[List[CommitStatus]] = {
@@ -95,7 +96,7 @@ trait PullRequestService {
         claReq   <- getRequest(endpoint)
         claRes   <- httpClient.expect(claReq)(jsonOf[CLASignature])
       } yield { (commit: Commit) =>
-        if (claRes.signed) Valid(user, commit)
+        if (claRes.signed) Valid(Some(user), commit)
         else Invalid(user, commit)
       }
 
@@ -117,33 +118,36 @@ trait PullRequestService {
     }.map(_.flatten)
   }
 
-  def sendStatuses(xs: List[CommitStatus], httpClient: Client): Task[List[StatusResponse]] = {
-    def setStatus(cm: CommitStatus): Task[StatusResponse] = {
-      val desc =
-        if (cm.isValid) "User signed CLA"
-        else "User needs to sign cla: https://www.lightbend.com/contribute/cla/scala"
-
-      val stat = cm match {
-        case Valid(user, commit) =>
-          Status("success", claUrl(user), desc)
-        case Invalid(user, commit) =>
-          Status("failure", claUrl(user), desc)
-        case MissingUser(commit) =>
-          Status("failure", "", "Missing valid github user for this PR")
-        case CLAServiceDown(user, commit) =>
-          Status("pending", claUrl(user), "CLA Service is down")
-      }
-
-      for {
-        endpoint <- toUri(statusUrl(cm.commit.sha))
-        req      <- postRequest(endpoint).withBody(stat.asJson)
-        res      <- httpClient.expect(req)(jsonOf[StatusResponse])
-      } yield res
+  def setStatus(cm: CommitStatus, httpClient: Client): Task[StatusResponse] = {
+    val desc =
+      if (cm.isValid) "User signed CLA"
+      else "User needs to sign cla: https://www.lightbend.com/contribute/cla/scala"
+
+    val stat = cm match {
+      case Valid(Some(user), commit) =>
+        Status("success", claUrl(user), desc)
+      case Valid(None, commit) =>
+        Status("success", "", "All contributors signed CLA")
+      case Invalid(user, commit) =>
+        Status("failure", claUrl(user), desc)
+      case MissingUser(commit) =>
+        Status("failure", "", "Missing valid github user for this PR")
+      case CLAServiceDown(user, commit) =>
+        Status("pending", claUrl(user), "CLA Service is down")
+      case InvalidPrevious(users, latestCommit) =>
+        Status("failure", "", users.map("@" + _).mkString(", ") + " have not signed the CLA")
     }
 
-    Task.gatherUnordered(xs.map(setStatus))
+    for {
+      endpoint <- toUri(statusUrl(cm.commit.sha))
+      req      <- postRequest(endpoint).withBody(stat.asJson)
+      res      <- httpClient.expect(req)(jsonOf[StatusResponse])
+    } yield res
   }
 
+  def sendStatuses(xs: List[CommitStatus], httpClient: Client): Task[List[StatusResponse]] =
+    Task.gatherUnordered(xs.map(setStatus(_, httpClient)))
+
   private[this] val ExtractLink = """<([^>]+)>; rel="([^"]+)"""".r
   def findNext(header: Option[Header]): Option[String] = header.flatMap { header =>
     val value = header.value
@@ -157,6 +161,7 @@ trait PullRequestService {
       .headOption
   }
 
+  /** Ordered from earliest to latest */
   def getCommits(issueNbr: Int, httpClient: Client): Task[List[Commit]] = {
     def makeRequest(url: String): Task[List[Commit]] =
       for {
@@ -180,20 +185,80 @@ trait PullRequestService {
       res      <- httpClient.expect(req)(jsonOf[List[Comment]])
     } yield res
 
-  def checkPullRequest(issue: Issue): Task[Response] = {
-    val httpClient = PooledHttp1Client()
 
+  private def usersFromInvalid(xs: List[CommitStatus]) =
+    xs.collect { case Invalid(user, _) => user }
+
+  def sendInitialComment(invalidUsers: List[String]): Task[Unit] = ???
+
+  def checkFreshPR(issue: Issue): Task[Response] = {
+
+    val httpClient = PooledHttp1Client()
     for {
-      // First get all the commits from the PR
       commits  <- getCommits(issue.number, httpClient)
-
-      // Then check the CLA of each commit for both author and committer
       statuses <- checkCLA(commits, httpClient)
 
-      // Send statuses to Github and exit
-      _        <- sendStatuses(statuses, httpClient)
-      _        <- shutdownClient(httpClient).pure[Task]
-      resp     <- Ok("All statuses checked")
+      (validStatuses, invalidStatuses) = statuses.partition(_.isValid)
+      invalidUsers = usersFromInvalid(invalidStatuses)
+
+      // Mark the invalid statuses:
+      _ <- sendStatuses(invalidStatuses, httpClient)
+
+      // Set status of last to indicate previous failures or all good:
+      _ <- {
+        if (invalidStatuses.nonEmpty)
+          setStatus(InvalidPrevious(invalidUsers, commits.last), httpClient)
+        else
+          setStatus(statuses.last, httpClient)
+      }
+
+      // Send positive comment:
+      _    <- sendInitialComment(invalidUsers)
+      _    <- shutdownClient(httpClient)
+      resp <- Ok("Fresh PR checked")
+    } yield resp
+
+  }
+
+  // TODO: Could this be done with `issueNbr` instead?
+  def getStatuses(commits: List[Commit], client: Client): Task[List[StatusResponse]] =
+    ???
+
+  private def extractCommit(status: StatusResponse): Task[Commit] =
+    ???
+
+  def recheckCLA(statuses: List[StatusResponse], client: Client): Task[List[CommitStatus]] =
+    for {
+      commits  <- Task.gatherUnordered(statuses.map(extractCommit))
+      statuses <- checkCLA(commits, client)
+    } yield statuses
+
+  def checkSynchronize(issue: Issue): Task[Response] = {
+    val httpClient = PooledHttp1Client()
+
+    for {
+      commits      <- getCommits(issue.number, httpClient)
+      statuses     <- getStatuses(commits, httpClient)
+      stillInvalid <- recheckCLA(statuses, httpClient)
+
+      // Set final commit status based on `stillInvalid`:
+      _ <- {
+        if (stillInvalid.nonEmpty)
+          setStatus(InvalidPrevious(usersFromInvalid(stillInvalid), commits.last), httpClient)
+        else {
+          val lastCommit = commits.last
+          setStatus(Valid(lastCommit.author.login, lastCommit), httpClient)
+        }
+      }
+      _    <- shutdownClient(httpClient)
+      resp <- Ok("Updated PR checked")
     } yield resp
   }
+
+  def checkPullRequest(issue: Issue): Task[Response] =
+    issue.action match {
+      case "opened" => checkFreshPR(issue)
+      case "synchronize" => checkSynchronize(issue)
+      case action => BadRequest(s"Unhandled action: $action")
+    }
 }
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index e3814deb47a1..8a825c6ff31f 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -9,6 +9,7 @@ object Github {
   )
 
   case class Issue(
+    action: String, // "opened", "reopened", "closed", "synchronize"
     number: Int,
     pull_request: Option[PullRequest]
   )
@@ -35,6 +36,7 @@ object Github {
     context: String = "CLA"
   )
 
+  // TODO: Can we get a `Commit` from `StatusResponse`? 
   case class StatusResponse(
     url: String,
     id: Long,

From 6a633efd80c5615aaae4d3d091fd143b56a0fc11 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Mon, 24 Apr 2017 11:52:29 +0200
Subject: [PATCH 3/9] Implement rechecking of CLA

---
 .../dotty/tools/bot/PullRequestService.scala  | 57 ++++++++++++-------
 bot/src/dotty/tools/bot/model/Github.scala    |  4 +-
 bot/test/PRServiceTests.scala                 | 27 +++++++++
 3 files changed, 66 insertions(+), 22 deletions(-)

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index 4fa7d1d21881..491adb7f211e 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -54,17 +54,19 @@ trait PullRequestService {
     currentVersion: String
   )
 
+  private[this] val githubUrl = "https://api.github.com"
+
   def claUrl(userName: String): String =
    s"https://www.lightbend.com/contribute/cla/scala/check/$userName"
 
   def commitsUrl(prNumber: Int): String =
-    s"https://api.github.com/repos/lampepfl/dotty/pulls/$prNumber/commits?per_page=100"
+    s"$githubUrl/repos/lampepfl/dotty/pulls/$prNumber/commits?per_page=100"
 
   def statusUrl(sha: String): String =
-    s"https://api.github.com/repos/lampepfl/dotty/statuses/$sha"
+    s"$githubUrl/repos/lampepfl/dotty/statuses/$sha"
 
   def issueCommentsUrl(issueNbr: Int): String =
-    s"https://api.github.com/repos/lampepfl/dotty/issues/$issueNbr/comments"
+    s"$githubUrl/repos/lampepfl/dotty/issues/$issueNbr/comments"
 
   def toUri(url: String): Task[Uri] =
     Uri.fromString(url).fold(Task.fail, Task.now)
@@ -201,7 +203,7 @@ trait PullRequestService {
       (validStatuses, invalidStatuses) = statuses.partition(_.isValid)
       invalidUsers = usersFromInvalid(invalidStatuses)
 
-      // Mark the invalid statuses:
+      // Mark the invalid commits:
       _ <- sendStatuses(invalidStatuses, httpClient)
 
       // Set status of last to indicate previous failures or all good:
@@ -220,35 +222,48 @@ trait PullRequestService {
 
   }
 
-  // TODO: Could this be done with `issueNbr` instead?
+  def getStatus(commit: Commit, client: Client): Task[StatusResponse] =
+    for {
+      endpoint <- toUri(statusUrl(commit.sha))
+      req      <- getRequest(endpoint)
+      res      <- client.expect(req)(jsonOf[List[StatusResponse]])
+    } yield res.head
+
   def getStatuses(commits: List[Commit], client: Client): Task[List[StatusResponse]] =
-    ???
+    Task.gatherUnordered(commits.map(getStatus(_, client)))
 
-  private def extractCommit(status: StatusResponse): Task[Commit] =
-    ???
+  private def extractCommitSha(status: StatusResponse): Task[String] =
+    Task.delay(status.sha)
+
+  def recheckCLA(statuses: List[StatusResponse], commits: List[Commit], client: Client): Task[List[CommitStatus]] = {
+    /** Return the matching commits from the SHAs */
+    def prunedCommits(shas: List[String]): Task[List[Commit]] =
+      Task.delay(commits.filter(cm => shas.contains(cm.sha)))
 
-  def recheckCLA(statuses: List[StatusResponse], client: Client): Task[List[CommitStatus]] =
     for {
-      commits  <- Task.gatherUnordered(statuses.map(extractCommit))
-      statuses <- checkCLA(commits, client)
+      commitShas <- Task.gatherUnordered(statuses.map(extractCommitSha))
+      commits    <- prunedCommits(commitShas)
+      statuses   <- checkCLA(commits, client)
     } yield statuses
+  }
 
   def checkSynchronize(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
 
     for {
-      commits      <- getCommits(issue.number, httpClient)
-      statuses     <- getStatuses(commits, httpClient)
-      stillInvalid <- recheckCLA(statuses, httpClient)
+      commits  <- getCommits(issue.number, httpClient)
+      statuses <- checkCLA(commits, httpClient)
+
+      (_, invalid) = statuses.partition(_.isValid)
+
+      _ <- sendStatuses(invalid, httpClient)
 
-      // Set final commit status based on `stillInvalid`:
+      // Set final commit status based on `invalid`:
       _ <- {
-        if (stillInvalid.nonEmpty)
-          setStatus(InvalidPrevious(usersFromInvalid(stillInvalid), commits.last), httpClient)
-        else {
-          val lastCommit = commits.last
-          setStatus(Valid(lastCommit.author.login, lastCommit), httpClient)
-        }
+        if (invalid.nonEmpty)
+          setStatus(InvalidPrevious(usersFromInvalid(invalid), commits.last), httpClient)
+        else
+          setStatus(statuses.last, httpClient)
       }
       _    <- shutdownClient(httpClient)
       resp <- Ok("Updated PR checked")
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index 8a825c6ff31f..9ff834d04483 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -41,7 +41,9 @@ object Github {
     url: String,
     id: Long,
     state: String
-  )
+  ) {
+    def sha: String = url.split('/').last
+  }
 
   case class Comment(user: Author)
 }
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index 2858b42c73fe..b6682f756e1e 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -103,4 +103,31 @@ class PRServiceTests extends PullRequestService {
 
     httpClient.shutdownNow()
   }
+
+  @Test def canGetStatus = {
+    val sha = "fa64b4b613fe5e78a5b4185b4aeda89e2f1446ff"
+    val commit = Commit(sha, Author(None), Author(None), CommitInfo(""))
+    val status = withClient(getStatus(commit, _))
+
+    assert(status.sha == sha, "someting wong")
+  }
+
+  @Test def canRecheckCLA = {
+    val shas =
+      "1d62587cb3f41dafd796b0c92ec1c22d95b879f9" ::
+      "ad60a386f488a16612c093576bf7bf4d9f0073bf" ::
+      Nil
+
+    val commits = shas.map { sha =>
+      Commit(sha, Author(Some("felixmulder")), Author(Some("felixmulder")), CommitInfo(""))
+    }
+
+    val statuses = shas.map { sha =>
+      StatusResponse("https://api.github.com/repos/lampepfl/dotty/statuses/" + sha, 0, "failure")
+    }
+
+    val rechecked = withClient(recheckCLA(statuses, commits, _))
+
+    assert(rechecked.forall(cs => cs.isValid), s"Should have set all statuses to valid, but got: $rechecked")
+  }
 }

From 426390764d88fabdd2044600febfb8988dd2b7a5 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Mon, 24 Apr 2017 11:52:37 +0200
Subject: [PATCH 4/9] Use `withClient` helper in all tests

---
 bot/test/PRServiceTests.scala | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index b6682f756e1e..89acfe9e5900 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -40,10 +40,8 @@ class PRServiceTests extends PullRequestService {
   }
 
   @Test def canGetAllCommitsFromPR = {
-    val httpClient = PooledHttp1Client()
     val issueNbr = 1941 // has 2 commits: https://github.com/lampepfl/dotty/pull/1941/commits
-
-    val List(c1, c2) = getCommits(issueNbr, httpClient).run
+    val List(c1, c2) = withClient(getCommits(issueNbr, _))
 
     assertEquals(
       "Represent untyped operators as Ident instead of Name",
@@ -57,10 +55,8 @@ class PRServiceTests extends PullRequestService {
   }
 
   @Test def canGetMoreThan100Commits = {
-    val httpClient = PooledHttp1Client()
     val issueNbr = 1840 // has >100 commits: https://github.com/lampepfl/dotty/pull/1840/commits
-
-    val numberOfCommits = getCommits(issueNbr, httpClient).run.length
+    val numberOfCommits = withClient(getCommits(issueNbr, _)).length
 
     assert(
       numberOfCommits > 100,
@@ -69,27 +65,24 @@ class PRServiceTests extends PullRequestService {
   }
 
   @Test def canGetComments = {
-    val comments: List[Comment] = withClient(c => getComments(2136, c))
+    val comments: List[Comment] = withClient(getComments(2136, _))
 
     assert(comments.find(_.user.login == Some("odersky")).isDefined,
            "Could not find Martin's comment on PR 2136")
   }
 
   @Test def canCheckCLA = {
-    val httpClient = PooledHttp1Client()
     val validUserCommit = Commit("sha-here", Author(Some("felixmulder")), Author(Some("felixmulder")), CommitInfo(""))
-    val statuses: List[CommitStatus] = checkCLA(validUserCommit :: Nil, httpClient).run
+    val statuses: List[CommitStatus] = withClient(checkCLA(validUserCommit :: Nil, _))
 
     assert(statuses.length == 1, s"wrong number of valid statuses: got ${statuses.length}, expected 1")
-    httpClient.shutdownNow()
   }
 
   @Test def canSetStatus = {
-    val httpClient = PooledHttp1Client()
     val sha = "fa64b4b613fe5e78a5b4185b4aeda89e2f1446ff"
     val status = Invalid("smarter", Commit(sha, Author(Some("smarter")), Author(Some("smarter")), CommitInfo("")))
 
-    val statuses: List[StatusResponse] = sendStatuses(status :: Nil, httpClient).run
+    val statuses: List[StatusResponse] = withClient(sendStatuses(status :: Nil, _))
 
     assert(
       statuses.length == 1,
@@ -100,8 +93,6 @@ class PRServiceTests extends PullRequestService {
       statuses.head.state == "failure",
       s"status set had wrong state, expected 'failure', got: ${statuses.head.state}"
     )
-
-    httpClient.shutdownNow()
   }
 
   @Test def canGetStatus = {

From 8494fc5460940edd31fdd651d8e1aeaa332b9044 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Mon, 24 Apr 2017 15:51:14 +0200
Subject: [PATCH 5/9] Implement posting initial comment

---
 .../dotty/tools/bot/PullRequestService.scala  | 98 +++++++++++++++++--
 bot/src/dotty/tools/bot/model/Github.scala    | 30 +++---
 bot/test/PRServiceTests.scala                 | 13 +++
 3 files changed, 120 insertions(+), 21 deletions(-)

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index 491adb7f211e..b184aba857cc 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -3,7 +3,7 @@ package dotty.tools.bot
 import org.http4s.{ Status => _, _ }
 import org.http4s.client.blaze._
 import org.http4s.client.Client
-import org.http4s.headers.Authorization
+import org.http4s.headers.{ Accept, Authorization }
 
 import cats.syntax.applicative._
 import scalaz.concurrent.Task
@@ -47,6 +47,10 @@ trait PullRequestService {
     new Authorization(creds)
   }
 
+  private[this] lazy val previewAcceptHeader =
+    Accept.parse("application/vnd.github.black-cat-preview+json")
+      .getOrElse(throw new Exception("Couldn't initialize accept header"))
+
   private final case class CLASignature(
     user: String,
     signed: Boolean,
@@ -68,14 +72,20 @@ trait PullRequestService {
   def issueCommentsUrl(issueNbr: Int): String =
     s"$githubUrl/repos/lampepfl/dotty/issues/$issueNbr/comments"
 
+  def reviewUrl(issueNbr: Int): String =
+    s"$githubUrl/repos/lampepfl/dotty/pulls/$issueNbr/reviews"
+
   def toUri(url: String): Task[Uri] =
     Uri.fromString(url).fold(Task.fail, Task.now)
 
   def getRequest(endpoint: Uri): Task[Request] =
-    Request(uri = endpoint, method = Method.GET).putHeaders(authHeader).pure[Task]
+    Request(uri = endpoint, method = Method.GET).putHeaders(authHeader)
+      .pure[Task]
 
   def postRequest(endpoint: Uri): Task[Request] =
-    Request(uri = endpoint, method = Method.POST).putHeaders(authHeader).pure[Task]
+    Request(uri = endpoint, method = Method.POST)
+      .putHeaders(authHeader, previewAcceptHeader)
+      .pure[Task]
 
   def shutdownClient(client: Client): Task[Unit] =
     client.shutdownNow().pure[Task]
@@ -191,11 +201,87 @@ trait PullRequestService {
   private def usersFromInvalid(xs: List[CommitStatus]) =
     xs.collect { case Invalid(user, _) => user }
 
-  def sendInitialComment(invalidUsers: List[String]): Task[Unit] = ???
+  def hasBadCommitMessages(commits: List[Commit]): Boolean =
+    commits.exists { cm =>
+      val firstLine = cm.commit.message.takeWhile(_ != '\n').trim.toLowerCase
+      val firstWord = firstLine.takeWhile(x => x != ':' && x != ' ')
+      val containsColon = firstLine.contains(':')
 
-  def checkFreshPR(issue: Issue): Task[Response] = {
+      val wrongTense = firstWord match {
+        case "added" | "fixed" | "removed" | "moved" | "changed" |
+             "finalized" | "re-added"
+        => true
+
+        case "adds" | "fixes" | "removes" | "moves" | "changes" |
+             "finalizes" | "re-adds"
+        => true
+
+        case _
+        => false
+      }
+
+      wrongTense || firstLine.last == '.' || firstLine.length > 100
+    }
 
+  def sendInitialComment(issueNbr: Int, invalidUsers: List[String], commits: List[Commit], client: Client): Task[ReviewResponse] = {
+
+    val cla = if (invalidUsers.nonEmpty) {
+      s"""|## CLA ##
+          |In order for us to be able to accept your contribution, all users
+          |must sign the Scala CLA.
+          |
+          |Users:
+          |${ invalidUsers.map("@" + _).mkString("- ", "\n- ", "") }
+          |
+          |Could you folks please sign the CLA? :pray:
+          |
+          |Please do this here: https://www.lightbend.com/contribute/cla/scala
+          |""".stripMargin
+    } else "All contributors have signed the CLA, thank you! :heart:"
+
+    val commitRules = if (hasBadCommitMessages(commits)) {
+      """|## Commit Messages ##
+         |We want to keep history, but for that to actually be useful we have
+         |some rules on how to format our commit messages ([relevant xkcd](https://xkcd.com/1296/)).
+         |
+         |Please stick to these guidelines for commit messages:
+         |
+         |> 1. Separate subject from body with a blank line
+         |> 1. When fixing an issue, start your commit message with `Fix #<ISSUE-NBR>: `
+         |> 1. Limit the subject line to 80 characters
+         |> 1. Capitalize the subject line
+         |> 1. Do not end the subject line with a period
+         |> 1. Use the imperative mood in the subject line ("Added" instead of "Add")
+         |> 1. Wrap the body at 80 characters
+         |> 1. Use the body to explain what and why vs. how
+         |>
+         |> adapted from https://chris.beams.io/posts/git-commit""".stripMargin
+    } else ""
+
+    val body =
+      s"""|Hello, and thank you for opening this PR! :tada:
+          |
+          |If you haven't already, please request a review from one of our
+          |collaborators (have no fear, we don't bite)!
+          |
+          |$cla
+          |
+          |$commitRules
+          |
+          |Have an awesome day! :sunny:""".stripMargin
+
+    val review = Review.comment(body)
+
+    for {
+      endpoint <- toUri(reviewUrl(issueNbr))
+      req      <- postRequest(endpoint).withBody(review.asJson)
+      res      <- client.expect(req)(jsonOf[ReviewResponse])
+    } yield res
+  }
+
+  def checkFreshPR(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
+
     for {
       commits  <- getCommits(issue.number, httpClient)
       statuses <- checkCLA(commits, httpClient)
@@ -215,7 +301,7 @@ trait PullRequestService {
       }
 
       // Send positive comment:
-      _    <- sendInitialComment(invalidUsers)
+      _    <- sendInitialComment(issue.number, invalidUsers, commits, httpClient)
       _    <- shutdownClient(httpClient)
       resp <- Ok("Fresh PR checked")
     } yield resp
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index 9ff834d04483..80bca3ad1042 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -2,21 +2,15 @@ package dotty.tools.bot
 package model
 
 object Github {
-  case class PullRequest(
-    url: String,
-    id: Long,
-    commits_url: String
-  )
-
   case class Issue(
     action: String, // "opened", "reopened", "closed", "synchronize"
     number: Int,
     pull_request: Option[PullRequest]
   )
 
-  case class CommitInfo(
-    message: String
-  )
+  case class PullRequest(url: String, id: Long, commits_url: String)
+
+  case class CommitInfo(message: String)
 
   case class Commit(
     sha: String,
@@ -36,14 +30,20 @@ object Github {
     context: String = "CLA"
   )
 
-  // TODO: Can we get a `Commit` from `StatusResponse`? 
-  case class StatusResponse(
-    url: String,
-    id: Long,
-    state: String
-  ) {
+  case class StatusResponse(url: String, id: Long, state: String) {
     def sha: String = url.split('/').last
   }
 
   case class Comment(user: Author)
+
+  /** A PR review */
+  case class Review (body: String, event: String)
+
+  object Review {
+    def approve(body: String) = Review(body, "APPROVE")
+    def requestChanges(body: String) = Review(body, "REQUEST_CHANGES")
+    def comment(body: String) = Review(body, "COMMENT")
+  }
+
+  case class ReviewResponse(body: String, state: String, id: Long)
 }
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index 89acfe9e5900..860438697d89 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -121,4 +121,17 @@ class PRServiceTests extends PullRequestService {
 
     assert(rechecked.forall(cs => cs.isValid), s"Should have set all statuses to valid, but got: $rechecked")
   }
+
+  @Test def canPostReview = {
+    val invalidUsers = "felixmulder" :: "smarter" :: Nil
+    val commit = Commit("", Author(Some("smarter")), Author(Some("smarter")), CommitInfo("Added stuff"))
+    val res = withClient(sendInitialComment(2281, invalidUsers, commit :: Nil, _))
+
+    assert(
+      res.body.contains("We want to keep history") &&
+      res.body.contains("Could you folks please sign the CLA?") &&
+      res.body.contains("Have an awesome day!"),
+      s"Body of review was not as expected:\n${res.body}"
+    )
+  }
 }

From 01da59f12a0a962967ffd42d24430cb6144f8722 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Tue, 25 Apr 2017 09:56:30 +0200
Subject: [PATCH 6/9] Factor out HTTP client functionality

---
 bot/src/dotty/tools/bot/Main.scala            |  7 +-
 .../dotty/tools/bot/PullRequestService.scala  | 96 ++++---------------
 .../dotty/tools/bot/util/HttpClientAux.scala  | 35 +++++++
 .../tools/bot/util/TaskIsApplicative.scala    | 13 +++
 bot/test/PRServiceTests.scala                 | 26 +----
 5 files changed, 77 insertions(+), 100 deletions(-)
 create mode 100644 bot/src/dotty/tools/bot/util/HttpClientAux.scala
 create mode 100644 bot/src/dotty/tools/bot/util/TaskIsApplicative.scala

diff --git a/bot/src/dotty/tools/bot/Main.scala b/bot/src/dotty/tools/bot/Main.scala
index 00b4a2735f94..8edd1dcc9cab 100644
--- a/bot/src/dotty/tools/bot/Main.scala
+++ b/bot/src/dotty/tools/bot/Main.scala
@@ -7,9 +7,10 @@ import scalaz.concurrent.Task
 
 object Main extends ServerApp with PullRequestService {
 
-  val user = sys.env("USER")
-  val token = sys.env("TOKEN")
-  val port = sys.env("PORT").toInt
+  val githubUser  = sys.env("GITHUB_USER")
+  val githubToken = sys.env("GITHUB_TOKEN")
+  val droneToken  = sys.env("DRONE_TOKEN")
+  val port        = sys.env("PORT").toInt
 
   /** Services mounted to the server */
   final val services = prService
diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index b184aba857cc..3d3861a757d9 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -1,4 +1,5 @@
-package dotty.tools.bot
+package dotty.tools
+package bot
 
 import org.http4s.{ Status => _, _ }
 import org.http4s.client.blaze._
@@ -18,23 +19,19 @@ import org.http4s.dsl._
 import org.http4s.util._
 
 import model.Github._
-
-object TaskIsApplicative {
-  implicit val taskIsApplicative = new cats.Applicative[Task] {
-    def pure[A](x: A): Task[A] = Task.now(x)
-    def ap[A, B](ff: Task[A => B])(fa: Task[A]): Task[B] =
-      for(f <- ff; a <- fa) yield f(a)
-  }
-}
-import TaskIsApplicative._
+import bot.util.TaskIsApplicative._
+import bot.util.HttpClientAux._
 
 trait PullRequestService {
 
   /** Username for authorized admin */
-  def user: String
+  def githubUser: String
 
   /** OAuth token needed for user to create statuses */
-  def token: String
+  def githubToken: String
+
+  /** OAuth token for drone, needed to cancel builds */
+  def droneToken: String
 
   /** Pull Request HTTP service */
   val prService = HttpService {
@@ -42,15 +39,6 @@ trait PullRequestService {
       request.as(jsonOf[Issue]).flatMap(checkPullRequest)
   }
 
-  private[this] lazy val authHeader = {
-    val creds = BasicCredentials(user, token)
-    new Authorization(creds)
-  }
-
-  private[this] lazy val previewAcceptHeader =
-    Accept.parse("application/vnd.github.black-cat-preview+json")
-      .getOrElse(throw new Exception("Couldn't initialize accept header"))
-
   private final case class CLASignature(
     user: String,
     signed: Boolean,
@@ -75,18 +63,6 @@ trait PullRequestService {
   def reviewUrl(issueNbr: Int): String =
     s"$githubUrl/repos/lampepfl/dotty/pulls/$issueNbr/reviews"
 
-  def toUri(url: String): Task[Uri] =
-    Uri.fromString(url).fold(Task.fail, Task.now)
-
-  def getRequest(endpoint: Uri): Task[Request] =
-    Request(uri = endpoint, method = Method.GET).putHeaders(authHeader)
-      .pure[Task]
-
-  def postRequest(endpoint: Uri): Task[Request] =
-    Request(uri = endpoint, method = Method.POST)
-      .putHeaders(authHeader, previewAcceptHeader)
-      .pure[Task]
-
   def shutdownClient(client: Client): Task[Unit] =
     client.shutdownNow().pure[Task]
 
@@ -104,9 +80,7 @@ trait PullRequestService {
   def checkCLA(xs: List[Commit], httpClient: Client): Task[List[CommitStatus]] = {
     def checkUser(user: String): Task[Commit => CommitStatus] = {
       val claStatus = for {
-        endpoint <- toUri(claUrl(user))
-        claReq   <- getRequest(endpoint)
-        claRes   <- httpClient.expect(claReq)(jsonOf[CLASignature])
+        claRes <- httpClient.expect(get(claUrl(user)))(jsonOf[CLASignature])
       } yield { (commit: Commit) =>
         if (claRes.signed) Valid(Some(user), commit)
         else Invalid(user, commit)
@@ -151,9 +125,8 @@ trait PullRequestService {
     }
 
     for {
-      endpoint <- toUri(statusUrl(cm.commit.sha))
-      req      <- postRequest(endpoint).withBody(stat.asJson)
-      res      <- httpClient.expect(req)(jsonOf[StatusResponse])
+      req <- post(statusUrl(cm.commit.sha)).withAuth(githubUser, githubToken)
+      res <- httpClient.expect(req.withBody(stat.asJson))(jsonOf[StatusResponse])
     } yield res
   }
 
@@ -177,9 +150,7 @@ trait PullRequestService {
   def getCommits(issueNbr: Int, httpClient: Client): Task[List[Commit]] = {
     def makeRequest(url: String): Task[List[Commit]] =
       for {
-        endpoint <- toUri(url)
-        req <- getRequest(endpoint)
-        res <- httpClient.fetch(req){ res =>
+        res <- httpClient.fetch(get(url)) { res =>
           val link = CaseInsensitiveString("Link")
           val next = findNext(res.headers.get(link)).map(makeRequest).getOrElse(Task.now(Nil))
 
@@ -191,12 +162,7 @@ trait PullRequestService {
   }
 
   def getComments(issueNbr: Int, httpClient: Client): Task[List[Comment]] =
-    for {
-      endpoint <- toUri(issueCommentsUrl(issueNbr))
-      req      <- getRequest(endpoint)
-      res      <- httpClient.expect(req)(jsonOf[List[Comment]])
-    } yield res
-
+    httpClient.expect(get(issueCommentsUrl(issueNbr)))(jsonOf[List[Comment]])
 
   private def usersFromInvalid(xs: List[CommitStatus]) =
     xs.collect { case Invalid(user, _) => user }
@@ -273,9 +239,8 @@ trait PullRequestService {
     val review = Review.comment(body)
 
     for {
-      endpoint <- toUri(reviewUrl(issueNbr))
-      req      <- postRequest(endpoint).withBody(review.asJson)
-      res      <- client.expect(req)(jsonOf[ReviewResponse])
+      req <- post(reviewUrl(issueNbr)).withAuth(githubUser, githubToken)
+      res <- client.expect(req.withBody(review.asJson))(jsonOf[ReviewResponse])
     } yield res
   }
 
@@ -308,30 +273,12 @@ trait PullRequestService {
 
   }
 
-  def getStatus(commit: Commit, client: Client): Task[StatusResponse] =
-    for {
-      endpoint <- toUri(statusUrl(commit.sha))
-      req      <- getRequest(endpoint)
-      res      <- client.expect(req)(jsonOf[List[StatusResponse]])
-    } yield res.head
-
-  def getStatuses(commits: List[Commit], client: Client): Task[List[StatusResponse]] =
-    Task.gatherUnordered(commits.map(getStatus(_, client)))
+  def getStatus(commit: Commit, client: Client): Task[List[StatusResponse]] =
+    client.expect(get(statusUrl(commit.sha)))(jsonOf[List[StatusResponse]])
 
   private def extractCommitSha(status: StatusResponse): Task[String] =
     Task.delay(status.sha)
 
-  def recheckCLA(statuses: List[StatusResponse], commits: List[Commit], client: Client): Task[List[CommitStatus]] = {
-    /** Return the matching commits from the SHAs */
-    def prunedCommits(shas: List[String]): Task[List[Commit]] =
-      Task.delay(commits.filter(cm => shas.contains(cm.sha)))
-
-    for {
-      commitShas <- Task.gatherUnordered(statuses.map(extractCommitSha))
-      commits    <- prunedCommits(commitShas)
-      statuses   <- checkCLA(commits, client)
-    } yield statuses
-  }
 
   def checkSynchronize(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
@@ -339,10 +286,9 @@ trait PullRequestService {
     for {
       commits  <- getCommits(issue.number, httpClient)
       statuses <- checkCLA(commits, httpClient)
-
-      (_, invalid) = statuses.partition(_.isValid)
-
-      _ <- sendStatuses(invalid, httpClient)
+      invalid  =  statuses.filterNot(_.isValid)
+      _        <- sendStatuses(invalid, httpClient)
+      _        <- cancelBuilds(commits.dropRight(1), httpClient)
 
       // Set final commit status based on `invalid`:
       _ <- {
diff --git a/bot/src/dotty/tools/bot/util/HttpClientAux.scala b/bot/src/dotty/tools/bot/util/HttpClientAux.scala
new file mode 100644
index 000000000000..d5fbe363dc14
--- /dev/null
+++ b/bot/src/dotty/tools/bot/util/HttpClientAux.scala
@@ -0,0 +1,35 @@
+package dotty.tools.bot.util
+
+import org.http4s._
+import scalaz.concurrent.Task
+import org.http4s.headers.{ Accept, Authorization }
+
+object HttpClientAux {
+  def uriFromString(url: String): Task[Uri] =
+    Uri.fromString(url).fold(Task.fail, Task.now)
+
+  implicit class RicherTask(val task: Task[Request]) extends AnyVal {
+    def withOauth2(token: String): Task[Request] =
+      task.map(_.putHeaders(new Authorization(new OAuth2BearerToken(token))))
+
+    def withAuth(user: String, pass: String): Task[Request] =
+      task.map(_.putHeaders(new Authorization(BasicCredentials(user, pass))))
+  }
+
+  private[this] lazy val previewAcceptHeader =
+    Accept.parse("application/vnd.github.black-cat-preview+json")
+      .getOrElse(throw new Exception("Couldn't initialize accept header"))
+
+  @inline private def request(method: Method, endpoint: Uri): Request =
+    Request(uri = endpoint, method = method)
+      .putHeaders(previewAcceptHeader)
+
+  def get(endpoint: String): Task[Request] =
+    uriFromString(endpoint).map(request(Method.GET, _))
+
+  def post(endpoint: String): Task[Request] =
+    uriFromString(endpoint).map(request(Method.POST, _))
+
+  def delete(endpoint: String): Task[Request] =
+    uriFromString(endpoint).map(request(Method.DELETE, _))
+}
diff --git a/bot/src/dotty/tools/bot/util/TaskIsApplicative.scala b/bot/src/dotty/tools/bot/util/TaskIsApplicative.scala
new file mode 100644
index 000000000000..c97b1ac5f456
--- /dev/null
+++ b/bot/src/dotty/tools/bot/util/TaskIsApplicative.scala
@@ -0,0 +1,13 @@
+package dotty.tools.bot
+package util
+
+import cats.syntax.applicative._
+import scalaz.concurrent.Task
+
+object TaskIsApplicative {
+  implicit val taskIsApplicative = new cats.Applicative[Task] {
+    def pure[A](x: A): Task[A] = Task.now(x)
+    def ap[A, B](ff: Task[A => B])(fa: Task[A]): Task[B] =
+      for(f <- ff; a <- fa) yield f(a)
+  }
+}
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index 860438697d89..4d827d6b86a8 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -14,8 +14,9 @@ import org.http4s.client.Client
 import scalaz.concurrent.Task
 
 class PRServiceTests extends PullRequestService {
-  val user = sys.env("USER")
-  val token = sys.env("TOKEN")
+  val githubUser  = sys.env("GITHUB_USER")
+  val githubToken = sys.env("GITHUB_TOKEN")
+  val droneToken  = sys.env("DRONE_TOKEN")
 
   private def withClient[A](f: Client => Task[A]): A = {
     val httpClient = PooledHttp1Client()
@@ -98,30 +99,11 @@ class PRServiceTests extends PullRequestService {
   @Test def canGetStatus = {
     val sha = "fa64b4b613fe5e78a5b4185b4aeda89e2f1446ff"
     val commit = Commit(sha, Author(None), Author(None), CommitInfo(""))
-    val status = withClient(getStatus(commit, _))
+    val status = withClient(getStatus(commit, _)).head
 
     assert(status.sha == sha, "someting wong")
   }
 
-  @Test def canRecheckCLA = {
-    val shas =
-      "1d62587cb3f41dafd796b0c92ec1c22d95b879f9" ::
-      "ad60a386f488a16612c093576bf7bf4d9f0073bf" ::
-      Nil
-
-    val commits = shas.map { sha =>
-      Commit(sha, Author(Some("felixmulder")), Author(Some("felixmulder")), CommitInfo(""))
-    }
-
-    val statuses = shas.map { sha =>
-      StatusResponse("https://api.github.com/repos/lampepfl/dotty/statuses/" + sha, 0, "failure")
-    }
-
-    val rechecked = withClient(recheckCLA(statuses, commits, _))
-
-    assert(rechecked.forall(cs => cs.isValid), s"Should have set all statuses to valid, but got: $rechecked")
-  }
-
   @Test def canPostReview = {
     val invalidUsers = "felixmulder" :: "smarter" :: Nil
     val commit = Commit("", Author(Some("smarter")), Author(Some("smarter")), CommitInfo("Added stuff"))

From 51f8bc1af0014e957c1dc815d6c25cdbb5898521 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Tue, 25 Apr 2017 11:07:27 +0200
Subject: [PATCH 7/9] Add ability for bot to stop outdated jobs

---
 .../dotty/tools/bot/PullRequestService.scala  | 16 +++++-
 bot/src/dotty/tools/bot/model/Drone.scala     | 49 +++++++++++++++++++
 bot/src/dotty/tools/bot/model/Github.scala    |  8 ++-
 bot/test/PRServiceTests.scala                 |  8 +++
 4 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 bot/src/dotty/tools/bot/model/Drone.scala

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index 3d3861a757d9..fb13b1c45bef 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -19,6 +19,7 @@ import org.http4s.dsl._
 import org.http4s.util._
 
 import model.Github._
+import model.Drone
 import bot.util.TaskIsApplicative._
 import bot.util.HttpClientAux._
 
@@ -279,6 +280,19 @@ trait PullRequestService {
   private def extractCommitSha(status: StatusResponse): Task[String] =
     Task.delay(status.sha)
 
+  def cancelBuilds(commits: List[Commit])(implicit client: Client): Task[Boolean] =
+    Task.gatherUnordered {
+      val droneContext = "continuous-integration/drone/pr"
+      commits.map { commit =>
+        for {
+          statuses    <- getStatus(commit, client)
+          cancellable =  statuses.filter(status => status.state == "pending" && status.context == droneContext)
+          runningJobs =  cancellable.map(_.target_url.split('/').last.toInt)
+          cancelled   <- Task.gatherUnordered(runningJobs.map(Drone.stopBuild(_, droneToken)))
+        } yield cancelled.foldLeft(true)(_ == _)
+      }
+    }
+    .map(xs => xs.foldLeft(true)(_ == _))
 
   def checkSynchronize(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
@@ -288,7 +302,7 @@ trait PullRequestService {
       statuses <- checkCLA(commits, httpClient)
       invalid  =  statuses.filterNot(_.isValid)
       _        <- sendStatuses(invalid, httpClient)
-      _        <- cancelBuilds(commits.dropRight(1), httpClient)
+      _        <- cancelBuilds(commits.dropRight(1))(httpClient)
 
       // Set final commit status based on `invalid`:
       _ <- {
diff --git a/bot/src/dotty/tools/bot/model/Drone.scala b/bot/src/dotty/tools/bot/model/Drone.scala
new file mode 100644
index 000000000000..710f18554333
--- /dev/null
+++ b/bot/src/dotty/tools/bot/model/Drone.scala
@@ -0,0 +1,49 @@
+package dotty.tools
+package bot
+package model
+
+import io.circe._
+import io.circe.generic.auto._
+import io.circe.syntax._
+
+import org.http4s._
+import org.http4s.circe._
+import org.http4s.client.Client
+
+import scalaz.concurrent.Task
+import bot.util.HttpClientAux
+
+object Drone {
+  import HttpClientAux._
+
+  case class Build(
+    number: Int,
+    event: String,
+    status: String,
+    commit: String,
+    author: String
+  )
+
+  private[this] val baseUrl = "http://dotty-ci.epfl.ch/api"
+
+  private def job(id: Int) =
+    s"$baseUrl/repos/lampepfl/dotty/builds/$id"
+
+  private def job(id: Int, subId: Int) =
+    s"$baseUrl/repos/lampepfl/dotty/builds/$id/$subId"
+
+  def stopBuild(id: Int, token: String)(implicit client: Client): Task[Boolean] = {
+    def resToBoolean(res: Response): Task[Boolean] = Task.now {
+      res.status.code >= 200 && res.status.code < 400
+    }
+
+    val responses = List(1, 2, 3, 4).map { subId =>
+      client.fetch(delete(job(id, subId)).withOauth2(token))(resToBoolean)
+    }
+
+    Task.gatherUnordered(responses).map(xs => xs.exists(_ == true))
+  }
+
+  def startBuild(id: Int, token: String)(implicit client: Client): Task[Build] =
+    client.expect(post(job(id)).withOauth2(token))(jsonOf[Build])
+}
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index 80bca3ad1042..f3465579360b 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -30,7 +30,13 @@ object Github {
     context: String = "CLA"
   )
 
-  case class StatusResponse(url: String, id: Long, state: String) {
+  case class StatusResponse(
+    url: String,
+    id: Long,
+    state: String,
+    context: String,
+    target_url: String
+  ) {
     def sha: String = url.split('/').last
   }
 
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index 4d827d6b86a8..f1b22ad68754 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -9,6 +9,7 @@ import io.circe.syntax._
 import io.circe.parser.decode
 
 import model.Github._
+import model.Drone
 import org.http4s.client.blaze._
 import org.http4s.client.Client
 import scalaz.concurrent.Task
@@ -116,4 +117,11 @@ class PRServiceTests extends PullRequestService {
       s"Body of review was not as expected:\n${res.body}"
     )
   }
+
+  @Test def canStartAndStopBuild = {
+    val build = withClient(implicit client => Drone.startBuild(1921, droneToken))
+    assert(build.status == "pending" || build.status == "building")
+    val killed = withClient(implicit client => Drone.stopBuild(1921, droneToken))
+    assert(killed, "Couldn't kill build")
+  }
 }

From aad721f1e6371f26e5c7527c71cf41b4bf412578 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Tue, 25 Apr 2017 15:27:48 +0200
Subject: [PATCH 8/9] Add ability for bot to restart things when mentioned

---
 .../dotty/tools/bot/PullRequestService.scala  | 134 +++++++++++-
 bot/src/dotty/tools/bot/model/Github.scala    |  12 +-
 bot/test/PRServiceTests.scala                 |  37 +++-
 .../test-mention-no-understandy.json          | 203 ++++++++++++++++++
 bot/test/resources/test-mention.json          | 203 ++++++++++++++++++
 5 files changed, 572 insertions(+), 17 deletions(-)
 create mode 100644 bot/test/resources/test-mention-no-understandy.json
 create mode 100644 bot/test/resources/test-mention.json

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index fb13b1c45bef..c95254e98f46 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -37,9 +37,29 @@ trait PullRequestService {
   /** Pull Request HTTP service */
   val prService = HttpService {
     case request @ POST -> Root =>
-      request.as(jsonOf[Issue]).flatMap(checkPullRequest)
+      val githubEvent =
+        request.headers
+          .get(CaseInsensitiveString("X-GitHub-Event"))
+          .map(_.value).getOrElse("")
+
+      githubEvent match {
+        case "pull_request" =>
+          request.as(jsonOf[Issue]).flatMap(checkPullRequest)
+
+        case "issue_comment" =>
+          request.as(jsonOf[IssueComment]).flatMap(respondToComment)
+
+        case "" =>
+          BadRequest("Missing header: X-Github-Event")
+
+        case event =>
+          BadRequest("Unsupported event: $event")
+
+      }
   }
 
+  private[this] val droneContext = "continuous-integration/drone/pr"
+
   private final case class CLASignature(
     user: String,
     signed: Boolean,
@@ -148,7 +168,7 @@ trait PullRequestService {
   }
 
   /** Ordered from earliest to latest */
-  def getCommits(issueNbr: Int, httpClient: Client): Task[List[Commit]] = {
+  def getCommits(issueNbr: Int)(implicit httpClient: Client): Task[List[Commit]] = {
     def makeRequest(url: String): Task[List[Commit]] =
       for {
         res <- httpClient.fetch(get(url)) { res =>
@@ -246,10 +266,10 @@ trait PullRequestService {
   }
 
   def checkFreshPR(issue: Issue): Task[Response] = {
-    val httpClient = PooledHttp1Client()
+    implicit val httpClient = PooledHttp1Client()
 
     for {
-      commits  <- getCommits(issue.number, httpClient)
+      commits  <- getCommits(issue.number)
       statuses <- checkCLA(commits, httpClient)
 
       (validStatuses, invalidStatuses) = statuses.partition(_.isValid)
@@ -280,9 +300,31 @@ trait PullRequestService {
   private def extractCommitSha(status: StatusResponse): Task[String] =
     Task.delay(status.sha)
 
+  def startBuild(commit: Commit)(implicit client: Client): Task[Drone.Build] = {
+    def pendingStatus(targetUrl: String): Status =
+      Status("pending", targetUrl, "build restarted by bot", droneContext)
+
+    def filterStatuses(xs: List[StatusResponse]): Task[Int] =
+      xs.filter { status =>
+        (status.state == "failure" || status.state == "success") &&
+        status.context == droneContext
+      }
+      .map(status => Task.now(status.target_url.split('/').last.toInt))
+      .headOption
+      .getOrElse(Task.fail(new NoSuchElementException("Couldn't find drone build for PR")))
+
+    for {
+      statuses     <- getStatus(commit, client)
+      failed       <- filterStatuses(statuses)
+      build        <- Drone.startBuild(failed, droneToken)
+      setStatusReq <- post(statusUrl(commit.sha)).withAuth(githubUser, githubToken)
+      newStatus    =  pendingStatus(s"http://dotty-ci.epfl.ch/lampepfl/dotty/$failed").asJson
+      _            <- client.expect(setStatusReq.withBody(newStatus))(jsonOf[StatusResponse])
+    } yield build
+  }
+
   def cancelBuilds(commits: List[Commit])(implicit client: Client): Task[Boolean] =
     Task.gatherUnordered {
-      val droneContext = "continuous-integration/drone/pr"
       commits.map { commit =>
         for {
           statuses    <- getStatus(commit, client)
@@ -295,10 +337,10 @@ trait PullRequestService {
     .map(xs => xs.foldLeft(true)(_ == _))
 
   def checkSynchronize(issue: Issue): Task[Response] = {
-    val httpClient = PooledHttp1Client()
+    implicit val httpClient = PooledHttp1Client()
 
     for {
-      commits  <- getCommits(issue.number, httpClient)
+      commits  <- getCommits(issue.number)
       statuses <- checkCLA(commits, httpClient)
       invalid  =  statuses.filterNot(_.isValid)
       _        <- sendStatuses(invalid, httpClient)
@@ -318,8 +360,80 @@ trait PullRequestService {
 
   def checkPullRequest(issue: Issue): Task[Response] =
     issue.action match {
-      case "opened" => checkFreshPR(issue)
-      case "synchronize" => checkSynchronize(issue)
-      case action => BadRequest(s"Unhandled action: $action")
+      case Some("opened") => checkFreshPR(issue)
+      case Some("synchronize") => checkSynchronize(issue)
+      case Some(action) => BadRequest(s"Unhandled action: $action")
+      case None => BadRequest("Cannot check pull request, missing action field")
+    }
+
+  def restartCI(issue: Issue): Task[Response] = {
+    implicit val client = PooledHttp1Client()
+
+    def restartedComment: Comment = {
+      import scala.util.Random
+      val answers = Array(
+        "Okidokey, boss! :clap:",
+        "You got it, homie! :pray:",
+        "No problem, big shot! :punch:",
+        "Sure thing, I got your back! :heart:",
+        "No WAY! :-1: ...wait, don't fire me please! There, I did it! :tada:"
+      )
+
+      Comment(Author(None), answers(Random.nextInt(answers.length)))
     }
+
+    for {
+      commits <- getCommits(issue.number)
+      latest  =  commits.last
+      _       <- cancelBuilds(latest :: Nil)
+      _       <- startBuild(latest)
+      req     <- post(issueCommentsUrl(issue.number)).withAuth(githubUser, githubToken)
+      _       <- client.fetch(req.withBody(restartedComment.asJson))(Task.now)
+      res     <- Ok("Replied to request for CI restart")
+    } yield res
+  }
+
+  def cannotUnderstand(line: String, issueComment: IssueComment): Task[Response] = {
+    implicit val client = PooledHttp1Client()
+    val comment = Comment(Author(None), {
+      s"""Hey, sorry - I could not understand what you meant by:
+         |
+         |> $line
+         |
+         |I'm just a dumb bot after all :cry:
+         |
+         |I mostly understand when your mention contains these words:
+         |
+         |- (re)check (the) cla
+         |- recheck
+         |- restart drone
+         |
+         |Maybe if you want to make me smarter, you could open a PR? :heart_eyes:
+         |""".stripMargin
+    })
+    for {
+      req <- post(issueCommentsUrl(issueComment.issue.number)).withAuth(githubUser, githubToken)
+      _   <- client.fetch(req.withBody(comment.asJson))(Task.now)
+      res <- Ok("Delivered could not understand comment")
+    } yield res
+  }
+
+  def extractMention(body: String): Option[String] =
+    body.lines.find(_.startsWith("@dotty-bot:"))
+
+  /** TODO: The implementation here could be quite elegant if we used a trie instead */
+  def interpretMention(line: String, issueComment: IssueComment): Task[Response] = {
+    val loweredLine = line.toLowerCase
+    if (loweredLine.contains("check cla") || loweredLine.contains("check the cla"))
+      checkSynchronize(issueComment.issue)
+    else if (loweredLine.contains("recheck") || loweredLine.contains("restart drone"))
+      restartCI(issueComment.issue)
+    else
+      cannotUnderstand(line, issueComment)
+  }
+
+  def respondToComment(issueComment: IssueComment): Task[Response] =
+    extractMention(issueComment.comment.body)
+      .map(interpretMention(_, issueComment))
+      .getOrElse(Ok("Nothing to do here, move along!"))
 }
diff --git a/bot/src/dotty/tools/bot/model/Github.scala b/bot/src/dotty/tools/bot/model/Github.scala
index f3465579360b..b28e57f669bc 100644
--- a/bot/src/dotty/tools/bot/model/Github.scala
+++ b/bot/src/dotty/tools/bot/model/Github.scala
@@ -3,12 +3,12 @@ package model
 
 object Github {
   case class Issue(
-    action: String, // "opened", "reopened", "closed", "synchronize"
+    action: Option[String], // "opened", "reopened", "closed", "synchronize"
     number: Int,
     pull_request: Option[PullRequest]
   )
 
-  case class PullRequest(url: String, id: Long, commits_url: String)
+  case class PullRequest(url: String, id: Option[Long], commits_url: Option[String])
 
   case class CommitInfo(message: String)
 
@@ -40,10 +40,8 @@ object Github {
     def sha: String = url.split('/').last
   }
 
-  case class Comment(user: Author)
-
   /** A PR review */
-  case class Review (body: String, event: String)
+  case class Review(body: String, event: String)
 
   object Review {
     def approve(body: String) = Review(body, "APPROVE")
@@ -52,4 +50,8 @@ object Github {
   }
 
   case class ReviewResponse(body: String, state: String, id: Long)
+
+  case class IssueComment(action: String, issue: Issue, comment: Comment)
+
+  case class Comment(user: Author, body: String)
 }
diff --git a/bot/test/PRServiceTests.scala b/bot/test/PRServiceTests.scala
index f1b22ad68754..f80def044a2d 100644
--- a/bot/test/PRServiceTests.scala
+++ b/bot/test/PRServiceTests.scala
@@ -41,9 +41,22 @@ class PRServiceTests extends PullRequestService {
     assert(issue.pull_request.isDefined, "missing pull request")
   }
 
+  @Test def canUnmarshalIssueComment = {
+    val json = getResource("/test-mention.json")
+    val issueComment: IssueComment = decode[IssueComment](json) match {
+      case Right(is: IssueComment) => is
+      case Left(ex) => throw ex
+    }
+
+    assert(
+      issueComment.comment.body == "@dotty-bot: could you recheck this please?",
+      s"incorrect body: ${issueComment.comment.body}"
+    )
+  }
+
   @Test def canGetAllCommitsFromPR = {
     val issueNbr = 1941 // has 2 commits: https://github.com/lampepfl/dotty/pull/1941/commits
-    val List(c1, c2) = withClient(getCommits(issueNbr, _))
+    val List(c1, c2) = withClient(implicit client => getCommits(issueNbr))
 
     assertEquals(
       "Represent untyped operators as Ident instead of Name",
@@ -58,7 +71,7 @@ class PRServiceTests extends PullRequestService {
 
   @Test def canGetMoreThan100Commits = {
     val issueNbr = 1840 // has >100 commits: https://github.com/lampepfl/dotty/pull/1840/commits
-    val numberOfCommits = withClient(getCommits(issueNbr, _)).length
+    val numberOfCommits = withClient(implicit client => getCommits(issueNbr)).length
 
     assert(
       numberOfCommits > 100,
@@ -124,4 +137,24 @@ class PRServiceTests extends PullRequestService {
     val killed = withClient(implicit client => Drone.stopBuild(1921, droneToken))
     assert(killed, "Couldn't kill build")
   }
+
+  @Test def canUnderstandWhenToRestartBuild = {
+    val json = getResource("/test-mention.json")
+    val issueComment: IssueComment = decode[IssueComment](json) match {
+      case Right(is: IssueComment) => is
+      case Left(ex) => throw ex
+    }
+
+    assert(respondToComment(issueComment).run.status.code == 200)
+  }
+
+  @Test def canTellUserWhenNotUnderstanding = {
+    val json = getResource("/test-mention-no-understandy.json")
+    val issueComment: IssueComment = decode[IssueComment](json) match {
+      case Right(is: IssueComment) => is
+      case Left(ex) => throw ex
+    }
+
+    assert(respondToComment(issueComment).run.status.code == 200)
+  }
 }
diff --git a/bot/test/resources/test-mention-no-understandy.json b/bot/test/resources/test-mention-no-understandy.json
new file mode 100644
index 000000000000..0b17d83de34e
--- /dev/null
+++ b/bot/test/resources/test-mention-no-understandy.json
@@ -0,0 +1,203 @@
+{
+  "action": "created",
+  "issue": {
+    "url": "https://api.github.com/repos/lampepfl/dotty/issues/2304",
+    "repository_url": "https://api.github.com/repos/lampepfl/dotty",
+    "labels_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/labels{/name}",
+    "comments_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/comments",
+    "events_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/events",
+    "html_url": "https://github.com/lampepfl/dotty/pull/2304",
+    "id": 224071012,
+    "number": 2304,
+    "title": "Bot improvements - CLA checks, killing old jobs, nagging about form",
+    "user": {
+      "login": "felixmulder",
+      "id": 1530049,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/felixmulder",
+      "html_url": "https://github.com/felixmulder",
+      "followers_url": "https://api.github.com/users/felixmulder/followers",
+      "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+      "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+      "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+      "repos_url": "https://api.github.com/users/felixmulder/repos",
+      "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+      "type": "User",
+      "site_admin": false
+    },
+    "labels": [
+
+    ],
+    "state": "open",
+    "locked": false,
+    "assignee": null,
+    "assignees": [
+
+    ],
+    "milestone": null,
+    "comments": 0,
+    "created_at": "2017-04-25T09:10:15Z",
+    "updated_at": "2017-04-25T11:34:20Z",
+    "closed_at": null,
+    "pull_request": {
+      "url": "https://api.github.com/repos/lampepfl/dotty/pulls/2304",
+      "html_url": "https://github.com/lampepfl/dotty/pull/2304",
+      "diff_url": "https://github.com/lampepfl/dotty/pull/2304.diff",
+      "patch_url": "https://github.com/lampepfl/dotty/pull/2304.patch"
+    },
+    "body": "Bot improvements include:\r\n\r\n- Deleting old jobs from PR, only keep the latest drone build\r\n- Check CLA and only approve last commit\r\n- Add some greetings to opened PRs helping people on where to sign CLA etc"
+  },
+  "comment": {
+    "url": "https://api.github.com/repos/lampepfl/dotty/issues/comments/297001946",
+    "html_url": "https://github.com/lampepfl/dotty/pull/2304#issuecomment-297001946",
+    "issue_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304",
+    "id": 297001946,
+    "user": {
+      "login": "felixmulder",
+      "id": 1530049,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/felixmulder",
+      "html_url": "https://github.com/felixmulder",
+      "followers_url": "https://api.github.com/users/felixmulder/followers",
+      "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+      "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+      "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+      "repos_url": "https://api.github.com/users/felixmulder/repos",
+      "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+      "type": "User",
+      "site_admin": false
+    },
+    "created_at": "2017-04-25T11:34:20Z",
+    "updated_at": "2017-04-25T11:34:20Z",
+    "body": "@dotty-bot: I don't like you."
+  },
+  "repository": {
+    "id": 7035651,
+    "name": "dotty",
+    "full_name": "lampepfl/dotty",
+    "owner": {
+      "login": "lampepfl",
+      "id": 2684793,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/2684793?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/lampepfl",
+      "html_url": "https://github.com/lampepfl",
+      "followers_url": "https://api.github.com/users/lampepfl/followers",
+      "following_url": "https://api.github.com/users/lampepfl/following{/other_user}",
+      "gists_url": "https://api.github.com/users/lampepfl/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/lampepfl/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/lampepfl/subscriptions",
+      "organizations_url": "https://api.github.com/users/lampepfl/orgs",
+      "repos_url": "https://api.github.com/users/lampepfl/repos",
+      "events_url": "https://api.github.com/users/lampepfl/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/lampepfl/received_events",
+      "type": "Organization",
+      "site_admin": false
+    },
+    "private": false,
+    "html_url": "https://github.com/lampepfl/dotty",
+    "description": "Research platform for new language concepts and compiler technologies for Scala.",
+    "fork": false,
+    "url": "https://api.github.com/repos/lampepfl/dotty",
+    "forks_url": "https://api.github.com/repos/lampepfl/dotty/forks",
+    "keys_url": "https://api.github.com/repos/lampepfl/dotty/keys{/key_id}",
+    "collaborators_url": "https://api.github.com/repos/lampepfl/dotty/collaborators{/collaborator}",
+    "teams_url": "https://api.github.com/repos/lampepfl/dotty/teams",
+    "hooks_url": "https://api.github.com/repos/lampepfl/dotty/hooks",
+    "issue_events_url": "https://api.github.com/repos/lampepfl/dotty/issues/events{/number}",
+    "events_url": "https://api.github.com/repos/lampepfl/dotty/events",
+    "assignees_url": "https://api.github.com/repos/lampepfl/dotty/assignees{/user}",
+    "branches_url": "https://api.github.com/repos/lampepfl/dotty/branches{/branch}",
+    "tags_url": "https://api.github.com/repos/lampepfl/dotty/tags",
+    "blobs_url": "https://api.github.com/repos/lampepfl/dotty/git/blobs{/sha}",
+    "git_tags_url": "https://api.github.com/repos/lampepfl/dotty/git/tags{/sha}",
+    "git_refs_url": "https://api.github.com/repos/lampepfl/dotty/git/refs{/sha}",
+    "trees_url": "https://api.github.com/repos/lampepfl/dotty/git/trees{/sha}",
+    "statuses_url": "https://api.github.com/repos/lampepfl/dotty/statuses/{sha}",
+    "languages_url": "https://api.github.com/repos/lampepfl/dotty/languages",
+    "stargazers_url": "https://api.github.com/repos/lampepfl/dotty/stargazers",
+    "contributors_url": "https://api.github.com/repos/lampepfl/dotty/contributors",
+    "subscribers_url": "https://api.github.com/repos/lampepfl/dotty/subscribers",
+    "subscription_url": "https://api.github.com/repos/lampepfl/dotty/subscription",
+    "commits_url": "https://api.github.com/repos/lampepfl/dotty/commits{/sha}",
+    "git_commits_url": "https://api.github.com/repos/lampepfl/dotty/git/commits{/sha}",
+    "comments_url": "https://api.github.com/repos/lampepfl/dotty/comments{/number}",
+    "issue_comment_url": "https://api.github.com/repos/lampepfl/dotty/issues/comments{/number}",
+    "contents_url": "https://api.github.com/repos/lampepfl/dotty/contents/{+path}",
+    "compare_url": "https://api.github.com/repos/lampepfl/dotty/compare/{base}...{head}",
+    "merges_url": "https://api.github.com/repos/lampepfl/dotty/merges",
+    "archive_url": "https://api.github.com/repos/lampepfl/dotty/{archive_format}{/ref}",
+    "downloads_url": "https://api.github.com/repos/lampepfl/dotty/downloads",
+    "issues_url": "https://api.github.com/repos/lampepfl/dotty/issues{/number}",
+    "pulls_url": "https://api.github.com/repos/lampepfl/dotty/pulls{/number}",
+    "milestones_url": "https://api.github.com/repos/lampepfl/dotty/milestones{/number}",
+    "notifications_url": "https://api.github.com/repos/lampepfl/dotty/notifications{?since,all,participating}",
+    "labels_url": "https://api.github.com/repos/lampepfl/dotty/labels{/name}",
+    "releases_url": "https://api.github.com/repos/lampepfl/dotty/releases{/id}",
+    "deployments_url": "https://api.github.com/repos/lampepfl/dotty/deployments",
+    "created_at": "2012-12-06T12:57:33Z",
+    "updated_at": "2017-04-23T22:50:39Z",
+    "pushed_at": "2017-04-25T11:28:03Z",
+    "git_url": "git://github.com/lampepfl/dotty.git",
+    "ssh_url": "git@github.com:lampepfl/dotty.git",
+    "clone_url": "https://github.com/lampepfl/dotty.git",
+    "svn_url": "https://github.com/lampepfl/dotty",
+    "homepage": "http://dotty.epfl.ch",
+    "size": 38144,
+    "stargazers_count": 1567,
+    "watchers_count": 1567,
+    "language": "Scala",
+    "has_issues": true,
+    "has_projects": true,
+    "has_downloads": true,
+    "has_wiki": false,
+    "has_pages": true,
+    "forks_count": 233,
+    "mirror_url": null,
+    "open_issues_count": 309,
+    "forks": 233,
+    "open_issues": 309,
+    "watchers": 1567,
+    "default_branch": "master"
+  },
+  "organization": {
+    "login": "lampepfl",
+    "id": 2684793,
+    "url": "https://api.github.com/orgs/lampepfl",
+    "repos_url": "https://api.github.com/orgs/lampepfl/repos",
+    "events_url": "https://api.github.com/orgs/lampepfl/events",
+    "hooks_url": "https://api.github.com/orgs/lampepfl/hooks",
+    "issues_url": "https://api.github.com/orgs/lampepfl/issues",
+    "members_url": "https://api.github.com/orgs/lampepfl/members{/member}",
+    "public_members_url": "https://api.github.com/orgs/lampepfl/public_members{/member}",
+    "avatar_url": "https://avatars2.githubusercontent.com/u/2684793?v=3",
+    "description": null
+  },
+  "sender": {
+    "login": "felixmulder",
+    "id": 1530049,
+    "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+    "gravatar_id": "",
+    "url": "https://api.github.com/users/felixmulder",
+    "html_url": "https://github.com/felixmulder",
+    "followers_url": "https://api.github.com/users/felixmulder/followers",
+    "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+    "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+    "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+    "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+    "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+    "repos_url": "https://api.github.com/users/felixmulder/repos",
+    "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+    "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+    "type": "User",
+    "site_admin": false
+  }
+}
diff --git a/bot/test/resources/test-mention.json b/bot/test/resources/test-mention.json
new file mode 100644
index 000000000000..d888e82c7234
--- /dev/null
+++ b/bot/test/resources/test-mention.json
@@ -0,0 +1,203 @@
+{
+  "action": "created",
+  "issue": {
+    "url": "https://api.github.com/repos/lampepfl/dotty/issues/2304",
+    "repository_url": "https://api.github.com/repos/lampepfl/dotty",
+    "labels_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/labels{/name}",
+    "comments_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/comments",
+    "events_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304/events",
+    "html_url": "https://github.com/lampepfl/dotty/pull/2304",
+    "id": 224071012,
+    "number": 2304,
+    "title": "Bot improvements - CLA checks, killing old jobs, nagging about form",
+    "user": {
+      "login": "felixmulder",
+      "id": 1530049,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/felixmulder",
+      "html_url": "https://github.com/felixmulder",
+      "followers_url": "https://api.github.com/users/felixmulder/followers",
+      "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+      "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+      "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+      "repos_url": "https://api.github.com/users/felixmulder/repos",
+      "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+      "type": "User",
+      "site_admin": false
+    },
+    "labels": [
+
+    ],
+    "state": "open",
+    "locked": false,
+    "assignee": null,
+    "assignees": [
+
+    ],
+    "milestone": null,
+    "comments": 0,
+    "created_at": "2017-04-25T09:10:15Z",
+    "updated_at": "2017-04-25T11:34:20Z",
+    "closed_at": null,
+    "pull_request": {
+      "url": "https://api.github.com/repos/lampepfl/dotty/pulls/2304",
+      "html_url": "https://github.com/lampepfl/dotty/pull/2304",
+      "diff_url": "https://github.com/lampepfl/dotty/pull/2304.diff",
+      "patch_url": "https://github.com/lampepfl/dotty/pull/2304.patch"
+    },
+    "body": "Bot improvements include:\r\n\r\n- Deleting old jobs from PR, only keep the latest drone build\r\n- Check CLA and only approve last commit\r\n- Add some greetings to opened PRs helping people on where to sign CLA etc"
+  },
+  "comment": {
+    "url": "https://api.github.com/repos/lampepfl/dotty/issues/comments/297001946",
+    "html_url": "https://github.com/lampepfl/dotty/pull/2304#issuecomment-297001946",
+    "issue_url": "https://api.github.com/repos/lampepfl/dotty/issues/2304",
+    "id": 297001946,
+    "user": {
+      "login": "felixmulder",
+      "id": 1530049,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/felixmulder",
+      "html_url": "https://github.com/felixmulder",
+      "followers_url": "https://api.github.com/users/felixmulder/followers",
+      "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+      "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+      "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+      "repos_url": "https://api.github.com/users/felixmulder/repos",
+      "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+      "type": "User",
+      "site_admin": false
+    },
+    "created_at": "2017-04-25T11:34:20Z",
+    "updated_at": "2017-04-25T11:34:20Z",
+    "body": "@dotty-bot: could you recheck this please?"
+  },
+  "repository": {
+    "id": 7035651,
+    "name": "dotty",
+    "full_name": "lampepfl/dotty",
+    "owner": {
+      "login": "lampepfl",
+      "id": 2684793,
+      "avatar_url": "https://avatars2.githubusercontent.com/u/2684793?v=3",
+      "gravatar_id": "",
+      "url": "https://api.github.com/users/lampepfl",
+      "html_url": "https://github.com/lampepfl",
+      "followers_url": "https://api.github.com/users/lampepfl/followers",
+      "following_url": "https://api.github.com/users/lampepfl/following{/other_user}",
+      "gists_url": "https://api.github.com/users/lampepfl/gists{/gist_id}",
+      "starred_url": "https://api.github.com/users/lampepfl/starred{/owner}{/repo}",
+      "subscriptions_url": "https://api.github.com/users/lampepfl/subscriptions",
+      "organizations_url": "https://api.github.com/users/lampepfl/orgs",
+      "repos_url": "https://api.github.com/users/lampepfl/repos",
+      "events_url": "https://api.github.com/users/lampepfl/events{/privacy}",
+      "received_events_url": "https://api.github.com/users/lampepfl/received_events",
+      "type": "Organization",
+      "site_admin": false
+    },
+    "private": false,
+    "html_url": "https://github.com/lampepfl/dotty",
+    "description": "Research platform for new language concepts and compiler technologies for Scala.",
+    "fork": false,
+    "url": "https://api.github.com/repos/lampepfl/dotty",
+    "forks_url": "https://api.github.com/repos/lampepfl/dotty/forks",
+    "keys_url": "https://api.github.com/repos/lampepfl/dotty/keys{/key_id}",
+    "collaborators_url": "https://api.github.com/repos/lampepfl/dotty/collaborators{/collaborator}",
+    "teams_url": "https://api.github.com/repos/lampepfl/dotty/teams",
+    "hooks_url": "https://api.github.com/repos/lampepfl/dotty/hooks",
+    "issue_events_url": "https://api.github.com/repos/lampepfl/dotty/issues/events{/number}",
+    "events_url": "https://api.github.com/repos/lampepfl/dotty/events",
+    "assignees_url": "https://api.github.com/repos/lampepfl/dotty/assignees{/user}",
+    "branches_url": "https://api.github.com/repos/lampepfl/dotty/branches{/branch}",
+    "tags_url": "https://api.github.com/repos/lampepfl/dotty/tags",
+    "blobs_url": "https://api.github.com/repos/lampepfl/dotty/git/blobs{/sha}",
+    "git_tags_url": "https://api.github.com/repos/lampepfl/dotty/git/tags{/sha}",
+    "git_refs_url": "https://api.github.com/repos/lampepfl/dotty/git/refs{/sha}",
+    "trees_url": "https://api.github.com/repos/lampepfl/dotty/git/trees{/sha}",
+    "statuses_url": "https://api.github.com/repos/lampepfl/dotty/statuses/{sha}",
+    "languages_url": "https://api.github.com/repos/lampepfl/dotty/languages",
+    "stargazers_url": "https://api.github.com/repos/lampepfl/dotty/stargazers",
+    "contributors_url": "https://api.github.com/repos/lampepfl/dotty/contributors",
+    "subscribers_url": "https://api.github.com/repos/lampepfl/dotty/subscribers",
+    "subscription_url": "https://api.github.com/repos/lampepfl/dotty/subscription",
+    "commits_url": "https://api.github.com/repos/lampepfl/dotty/commits{/sha}",
+    "git_commits_url": "https://api.github.com/repos/lampepfl/dotty/git/commits{/sha}",
+    "comments_url": "https://api.github.com/repos/lampepfl/dotty/comments{/number}",
+    "issue_comment_url": "https://api.github.com/repos/lampepfl/dotty/issues/comments{/number}",
+    "contents_url": "https://api.github.com/repos/lampepfl/dotty/contents/{+path}",
+    "compare_url": "https://api.github.com/repos/lampepfl/dotty/compare/{base}...{head}",
+    "merges_url": "https://api.github.com/repos/lampepfl/dotty/merges",
+    "archive_url": "https://api.github.com/repos/lampepfl/dotty/{archive_format}{/ref}",
+    "downloads_url": "https://api.github.com/repos/lampepfl/dotty/downloads",
+    "issues_url": "https://api.github.com/repos/lampepfl/dotty/issues{/number}",
+    "pulls_url": "https://api.github.com/repos/lampepfl/dotty/pulls{/number}",
+    "milestones_url": "https://api.github.com/repos/lampepfl/dotty/milestones{/number}",
+    "notifications_url": "https://api.github.com/repos/lampepfl/dotty/notifications{?since,all,participating}",
+    "labels_url": "https://api.github.com/repos/lampepfl/dotty/labels{/name}",
+    "releases_url": "https://api.github.com/repos/lampepfl/dotty/releases{/id}",
+    "deployments_url": "https://api.github.com/repos/lampepfl/dotty/deployments",
+    "created_at": "2012-12-06T12:57:33Z",
+    "updated_at": "2017-04-23T22:50:39Z",
+    "pushed_at": "2017-04-25T11:28:03Z",
+    "git_url": "git://github.com/lampepfl/dotty.git",
+    "ssh_url": "git@github.com:lampepfl/dotty.git",
+    "clone_url": "https://github.com/lampepfl/dotty.git",
+    "svn_url": "https://github.com/lampepfl/dotty",
+    "homepage": "http://dotty.epfl.ch",
+    "size": 38144,
+    "stargazers_count": 1567,
+    "watchers_count": 1567,
+    "language": "Scala",
+    "has_issues": true,
+    "has_projects": true,
+    "has_downloads": true,
+    "has_wiki": false,
+    "has_pages": true,
+    "forks_count": 233,
+    "mirror_url": null,
+    "open_issues_count": 309,
+    "forks": 233,
+    "open_issues": 309,
+    "watchers": 1567,
+    "default_branch": "master"
+  },
+  "organization": {
+    "login": "lampepfl",
+    "id": 2684793,
+    "url": "https://api.github.com/orgs/lampepfl",
+    "repos_url": "https://api.github.com/orgs/lampepfl/repos",
+    "events_url": "https://api.github.com/orgs/lampepfl/events",
+    "hooks_url": "https://api.github.com/orgs/lampepfl/hooks",
+    "issues_url": "https://api.github.com/orgs/lampepfl/issues",
+    "members_url": "https://api.github.com/orgs/lampepfl/members{/member}",
+    "public_members_url": "https://api.github.com/orgs/lampepfl/public_members{/member}",
+    "avatar_url": "https://avatars2.githubusercontent.com/u/2684793?v=3",
+    "description": null
+  },
+  "sender": {
+    "login": "felixmulder",
+    "id": 1530049,
+    "avatar_url": "https://avatars2.githubusercontent.com/u/1530049?v=3",
+    "gravatar_id": "",
+    "url": "https://api.github.com/users/felixmulder",
+    "html_url": "https://github.com/felixmulder",
+    "followers_url": "https://api.github.com/users/felixmulder/followers",
+    "following_url": "https://api.github.com/users/felixmulder/following{/other_user}",
+    "gists_url": "https://api.github.com/users/felixmulder/gists{/gist_id}",
+    "starred_url": "https://api.github.com/users/felixmulder/starred{/owner}{/repo}",
+    "subscriptions_url": "https://api.github.com/users/felixmulder/subscriptions",
+    "organizations_url": "https://api.github.com/users/felixmulder/orgs",
+    "repos_url": "https://api.github.com/users/felixmulder/repos",
+    "events_url": "https://api.github.com/users/felixmulder/events{/privacy}",
+    "received_events_url": "https://api.github.com/users/felixmulder/received_events",
+    "type": "User",
+    "site_admin": false
+  }
+}
\ No newline at end of file

From 595602d762c6271db4c71915ca5118d4e4599f4d Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Thu, 27 Apr 2017 09:49:19 +0200
Subject: [PATCH 9/9] Get rid of unnecessary `foldLeft`s and `shutdownClient`

---
 .../dotty/tools/bot/PullRequestService.scala  | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/bot/src/dotty/tools/bot/PullRequestService.scala b/bot/src/dotty/tools/bot/PullRequestService.scala
index c95254e98f46..afe5f10ce623 100644
--- a/bot/src/dotty/tools/bot/PullRequestService.scala
+++ b/bot/src/dotty/tools/bot/PullRequestService.scala
@@ -84,9 +84,6 @@ trait PullRequestService {
   def reviewUrl(issueNbr: Int): String =
     s"$githubUrl/repos/lampepfl/dotty/pulls/$issueNbr/reviews"
 
-  def shutdownClient(client: Client): Task[Unit] =
-    client.shutdownNow().pure[Task]
-
   sealed trait CommitStatus {
     def commit: Commit
     def isValid: Boolean
@@ -207,7 +204,7 @@ trait PullRequestService {
         => false
       }
 
-      wrongTense || firstLine.last == '.' || firstLine.length > 100
+      wrongTense || firstLine.last == '.' || firstLine.length > 80
     }
 
   def sendInitialComment(issueNbr: Int, invalidUsers: List[String], commits: List[Commit], client: Client): Task[ReviewResponse] = {
@@ -235,7 +232,7 @@ trait PullRequestService {
          |
          |> 1. Separate subject from body with a blank line
          |> 1. When fixing an issue, start your commit message with `Fix #<ISSUE-NBR>: `
-         |> 1. Limit the subject line to 80 characters
+         |> 1. Limit the subject line to 72 characters
          |> 1. Capitalize the subject line
          |> 1. Do not end the subject line with a period
          |> 1. Use the imperative mood in the subject line ("Added" instead of "Add")
@@ -288,7 +285,7 @@ trait PullRequestService {
 
       // Send positive comment:
       _    <- sendInitialComment(issue.number, invalidUsers, commits, httpClient)
-      _    <- shutdownClient(httpClient)
+      _    <- httpClient.shutdown
       resp <- Ok("Fresh PR checked")
     } yield resp
 
@@ -331,10 +328,10 @@ trait PullRequestService {
           cancellable =  statuses.filter(status => status.state == "pending" && status.context == droneContext)
           runningJobs =  cancellable.map(_.target_url.split('/').last.toInt)
           cancelled   <- Task.gatherUnordered(runningJobs.map(Drone.stopBuild(_, droneToken)))
-        } yield cancelled.foldLeft(true)(_ == _)
+        } yield cancelled.forall(identity)
       }
     }
-    .map(xs => xs.foldLeft(true)(_ == _))
+    .map(_.forall(identity))
 
   def checkSynchronize(issue: Issue): Task[Response] = {
     implicit val httpClient = PooledHttp1Client()
@@ -353,7 +350,7 @@ trait PullRequestService {
         else
           setStatus(statuses.last, httpClient)
       }
-      _    <- shutdownClient(httpClient)
+      _    <- httpClient.shutdown
       resp <- Ok("Updated PR checked")
     } yield resp
   }
@@ -421,7 +418,16 @@ trait PullRequestService {
   def extractMention(body: String): Option[String] =
     body.lines.find(_.startsWith("@dotty-bot:"))
 
-  /** TODO: The implementation here could be quite elegant if we used a trie instead */
+  /** Try to make sense of what the user is requesting from the bot
+   *
+   *  The bot's abilities currently only include:
+   *
+   *  - Checking or re-checking the CLA
+   *  - Restarting the CI tests
+   *
+   *  @note The implementation here could be quite elegant if we used a trie
+   *        instead
+   */
   def interpretMention(line: String, issueComment: IssueComment): Task[Response] = {
     val loweredLine = line.toLowerCase
     if (loweredLine.contains("check cla") || loweredLine.contains("check the cla"))