Send completion metadata to frontends

build.sc

@@ -565,7 +565,8 @@ class TestDefinitions(val crossScalaVersion: String) extends CrossSbtModule with
     shared.`test-kit`()
   )
   def ivyDeps = Agg(
-    Deps.coursierApi
+    Deps.coursierApi,
+    Deps.upickle
   )
 }
 

modules/echo/src/main/scala/almond/echo/EchoInterpreter.scala

@@ -72,6 +72,7 @@ final class EchoInterpreter extends Interpreter {
         pos,
         pos,
         Seq("sent"),
+        None,
         RawJson(code.drop("meta:".length).getBytes(StandardCharsets.UTF_8))
       )
     else

modules/scala/integration/src/main/scala/almond/integration/KernelTestsDefinitions.scala

@@ -138,4 +138,11 @@ abstract class KernelTestsDefinitions extends AlmondFunSuite {
     }
   }
 
+  test("completion") {
+    kernelLauncher.withKernel { implicit runner =>
+      implicit val sessionId: SessionId = SessionId()
+      almond.integration.Tests.completion(kernelLauncher.defaultScalaVersion)
+    }
+  }
+
 }

modules/scala/scala-interpreter/src/main/scala-2/almond/internals/ScalaInterpreterCompletions.scala

@@ -0,0 +1,324 @@
+package almond.internals
+
+import almond.logger.LoggerContext
+import ammonite.util.Name
+import ammonite.util.Util.newLine
+
+import java.io.{OutputStream, PrintWriter}
+
+import scala.reflect.internal.util.{BatchSourceFile, OffsetPosition, Position}
+import scala.tools.nsc
+import scala.tools.nsc.interactive.Response
+import scala.util.Try
+
+object ScalaInterpreterCompletions {
+
+  // Based on https://github.com/com-lihaoyi/Ammonite/blob/7699698ecedd4e01912df373f250b6a4e20c9a33/amm/compiler/src/main/scala-2/ammonite/compiler/Pressy.scala#L312-L313
+  // and around.
+  // Most changes revolve around keeping "kind" info ("method", "class", "value", etc.)
+
+  def complete(
+    compilerManager: ammonite.compiler.iface.CompilerLifecycleManager,
+    dependencyCompleteOpt: Option[String => (Int, Seq[String])],
+    snippetIndex: Int,
+    previousImports: String,
+    snippet: String,
+    logCtx: LoggerContext
+  ): (Int, Seq[String], Seq[String], Seq[(String, String)]) = {
+
+    val log = logCtx(getClass)
+
+    val prefix  = previousImports + newLine + "object AutocompleteWrapper{" + newLine
+    val suffix  = newLine + "}"
+    val allCode = prefix + snippet + suffix
+    val index   = snippetIndex + prefix.length
+
+    val compilerManager0 = compilerManager match {
+      case m: ammonite.compiler.CompilerLifecycleManager => m
+      case _                                             => ???
+    }
+    val pressy = compilerManager0.pressy.compiler
+    val currentFile = new BatchSourceFile(
+      ammonite.compiler.Compiler.makeFile(allCode.getBytes, name = "Current.sc"),
+      allCode
+    )
+
+    val r = new Response[Unit]
+    pressy.askReload(List(currentFile), r)
+    r.get.fold(x => x, e => throw e)
+
+    val run = Try(new Run(pressy, currentFile, dependencyCompleteOpt, allCode, index, logCtx))
+
+    val (i, all): (Int, Seq[(String, Option[String], String)]) =
+      run.map(_.prefixed).toEither match {
+        case Right((i0, all0)) => i0 -> all0
+        case Left(ex) =>
+          log.info("Ignoring exception during completion", ex)
+          (0, Seq.empty)
+      }
+
+    val allNames = all.collect { case (name, None, _) => name }.sorted.distinct
+
+    val allNameWithTypes = all.collect { case (name, None, tpe) => (name, tpe) }.sorted.distinct
+
+    val signatures = all.collect { case (name, Some(defn), _) => defn }.sorted.distinct
+
+    log.info(s"signatures=$signatures")
+
+    val isPartialIvyImport = allNames.isEmpty &&
+      snippet.split("\\s+|`").startsWith(Seq("import", "$ivy.")) &&
+      snippet.count(_ == '`') == 1
+
+    if (isPartialIvyImport)
+      complete(
+        compilerManager,
+        dependencyCompleteOpt,
+        snippetIndex,
+        previousImports,
+        snippet + "`",
+        logCtx
+      )
+    else (i - prefix.length, allNames, signatures, allNameWithTypes)
+  }
+
+  class Run(
+    val pressy: nsc.interactive.Global,
+    currentFile: BatchSourceFile,
+    dependencyCompleteOpt: Option[String => (Int, Seq[String])],
+    allCode: String,
+    index: Int,
+    logCtx: LoggerContext
+  ) {
+
+    val log = logCtx(getClass)
+
+    val blacklistedPackages = Set("shaded")
+
+    /** Dumb things that turn up in the autocomplete that nobody needs or wants
+      */
+    def blacklisted(s: pressy.Symbol) = {
+      val blacklist = Set(
+        "scala.Predef.any2stringadd.+",
+        "scala.Any.##",
+        "java.lang.Object.##",
+        "scala.<byname>",
+        "scala.<empty>",
+        "scala.<repeated>",
+        "scala.<repeated...>",
+        "scala.Predef.StringFormat.formatted",
+        "scala.Predef.Ensuring.ensuring",
+        "scala.Predef.ArrowAssoc.->",
+        "scala.Predef.ArrowAssoc.→",
+        "java.lang.Object.synchronized",
+        "java.lang.Object.ne",
+        "java.lang.Object.eq",
+        "java.lang.Object.wait",
+        "java.lang.Object.notifyAll",
+        "java.lang.Object.notify"
+      )
+
+      blacklist(s.fullNameAsName('.').decoded) ||
+      s.isImplicit ||
+      // Cache objects, which you should probably never need to
+      // access directly, and apart from that have annoyingly long names
+      "cache[a-f0-9]{32}".r.findPrefixMatchOf(s.name.decoded).isDefined ||
+      s.isDeprecated ||
+      s.decodedName == "<init>" ||
+      s.decodedName.contains('$')
+    }
+
+    private val memberToString = {
+      // Some hackery here to get at the protected CodePrinter.printedName which was the only
+      // mildly reusable prior art I could locate. Other related bits:
+      // - When constructing Trees, Scala captures the back-quoted nature into the AST as
+      //   Ident.isBackquoted. Code-completion is inherently "pre-Tree", at least for the
+      //   symbols being considered for use as completions, so not clear how this would be
+      //   leveragable without big changes inside nsc.
+      // - There's a public-but-incomplete implementation of rule-based backquoting in
+      //   Printers.quotedName
+      val nullOutputStream = new OutputStream() { def write(b: Int): Unit = {} }
+      val backQuoter = new pressy.CodePrinter(
+        new PrintWriter(nullOutputStream),
+        printRootPkg = false
+      ) {
+        def apply(decodedName: pressy.Name): String = printedName(decodedName, decoded = true)
+      }
+
+      (member: pressy.Member) => {
+        import pressy._
+        // nsc returns certain members w/ a suffix (LOCAL_SUFFIX_STRING, " ").
+        // See usages of symNameDropLocal in nsc's PresentationCompilerCompleter.
+        // Several people have asked that Scala mask this implementation detail:
+        // https://github.com/scala/bug/issues/5736
+        val decodedName = member.sym.name.dropLocal.decodedName
+        backQuoter(decodedName)
+      }
+    }
+
+    val r = new Response[pressy.Tree]
+    pressy.askTypeAt(new OffsetPosition(currentFile, index), r)
+    val tree = r.get.fold(x => x, e => throw e)
+
+    /** Search for terms to autocomplete not just from the local scope, but from any packages and
+      * package objects accessible from the local scope
+      */
+    def deepCompletion(name: String): List[(String, String)] = {
+      def rec(t: pressy.Symbol): Seq[pressy.Symbol] =
+        if (blacklistedPackages(t.nameString))
+          Nil
+        else {
+          val children =
+            if (t.hasPackageFlag || t.isPackageObject)
+              pressy.ask(() => t.typeSignature.members.filter(_ != t).flatMap(rec))
+            else Nil
+
+          t +: children.toSeq
+        }
+
+      for {
+        member <- pressy.RootClass.typeSignature.members.toList
+        sym    <- rec(member)
+        // sketchy name munging because I don't know how to do this properly
+        // Note lack of back-quoting support.
+        strippedName = sym.nameString.stripPrefix("package$").stripSuffix("$")
+        if strippedName.startsWith(name)
+        (pref, _) = sym.fullNameString.splitAt(sym.fullNameString.lastIndexOf('.') + 1)
+        out       = pref + strippedName
+        if out != ""
+      } yield (out, sym.kindString)
+    }
+    def handleTypeCompletion(
+      position: Int,
+      decoded: String,
+      offset: Int
+    ): (Int, List[(String, Option[String], String)]) = {
+
+      val r      = ask(position, pressy.askTypeCompletion)
+      val prefix = if (decoded == "<error>") "" else decoded
+      (position + offset, handleCompletion(r, prefix))
+    }
+
+    def handleCompletion(
+      r: List[pressy.Member],
+      prefix: String
+    ): List[(String, Option[String], String)] = pressy.ask { () =>
+      log.info(
+        s"response=$newLine${r.map(m => "  " + Try(m.toString).getOrElse("???") + newLine).mkString}"
+      )
+      r.filter(_.sym.name.decoded.startsWith(prefix))
+        .filter(m => !blacklisted(m.sym))
+        .map { x =>
+          (
+            memberToString(x),
+            if (x.sym.name.decoded != prefix) None
+            else Some(x.sym.defString),
+            x.sym.kindString
+          )
+        }
+    }
+
+    def prefixed: (Int, Seq[(String, Option[String], String)]) = tree match {
+      case t @ pressy.Select(qualifier, name) =>
+        val dotOffset = if (qualifier.pos.point == t.pos.point) 0 else 1
+
+        // In scala 2.10.x if we call pos.end on a scala.reflect.internal.util.Position
+        // that is not a range, a java.lang.UnsupportedOperationException is thrown.
+        // We check here if Position is a range before calling .end on it.
+        // This is not needed for scala 2.11.x.
+        if (qualifier.pos.isRange)
+          handleTypeCompletion(qualifier.pos.end, name.decoded, dotOffset)
+        else
+          // not prefixed
+          (0, Seq.empty)
+
+      case t @ pressy.Import(expr, selectors) =>
+        // If the selectors haven't been defined yet...
+        if (selectors.head.name.toString == "<error>")
+          if (expr.tpe.toString == "<error>")
+            // If the expr is badly typed, try to scope complete it
+            if (expr.isInstanceOf[pressy.Ident]) {
+              val exprName = expr.asInstanceOf[pressy.Ident].name.decoded
+              val pos =
+                // Without the first case, things like `import <caret>` are
+                // returned a wrong position.
+                if (exprName == "<error>") expr.pos.point - 1
+                else expr.pos.point
+              pos -> handleCompletion(
+                ask(expr.pos.point, pressy.askScopeCompletion),
+                // if it doesn't have a name at all, accept anything
+                if (exprName == "<error>") "" else exprName
+              )
+            }
+            else (expr.pos.point, Seq.empty)
+          else
+            // If the expr is well typed, type complete
+            // the next thing
+            handleTypeCompletion(expr.pos.end, "", 1)
+        else {
+          val isImportIvy = expr.isInstanceOf[pressy.Ident] &&
+            expr.asInstanceOf[pressy.Ident].name.decoded == "$ivy"
+          val selector = selectors
+            .filter(s => Math.max(s.namePos, s.renamePos) <= index)
+            .lastOption
+            .getOrElse(selectors.last)
+
+          if (isImportIvy) {
+            def forceOpenedBacktick(s: String): String = {
+              val res = Name(s).backticked
+              if (res.startsWith("`")) res.stripSuffix("`")
+              else "`" + res
+            }
+            dependencyCompleteOpt match {
+              case None => (0, Seq.empty[(String, Option[String], String)])
+              case Some(complete) =>
+                val input              = selector.name.decoded
+                val (pos, completions) = complete(input)
+                val input0             = input.take(pos)
+                (
+                  selector.namePos,
+                  completions.map(s => (forceOpenedBacktick(input0 + s), None, "dependency"))
+                )
+            }
+          }
+          else
+            // just use typeCompletion
+            handleTypeCompletion(selector.namePos, selector.name.decoded, 0)
+        }
+      case t @ pressy.Ident(name) =>
+        lazy val shallow = handleCompletion(
+          ask(index, pressy.askScopeCompletion),
+          name.decoded
+        )
+        lazy val deep = deepCompletion(name.decoded).distinct.map(t => (t._1, None, t._2))
+
+        val res =
+          if (shallow.length > 0) shallow
+          else if (deep.length == 1) deep
+          else deep :+ (("", None, ""))
+
+        (t.pos.start, res)
+
+      case t =>
+        val comps = ask(index, pressy.askScopeCompletion)
+
+        index -> pressy.ask(() =>
+          comps.filter(m => !blacklisted(m.sym))
+            .map(s => (memberToString(s), None, s.sym.kindString))
+        )
+    }
+    def ask(index: Int, query: (Position, Response[List[pressy.Member]]) => Unit) = {
+      val position = new OffsetPosition(currentFile, index)
+      // if a match can't be found awaitResponse throws an Exception.
+      val result = Try {
+        ammonite.compiler.Compiler.awaitResponse[List[pressy.Member]](
+          query(position, _)
+        )
+      }
+      result.toEither match {
+        case Right(scopes) => scopes.filter(_.accessible)
+        case Left(error)   => List.empty[pressy.Member]
+      }
+    }
+  }
+
+}