Tab completion after def results in an NPE

[edwardsmatt]

If you type def and hit tab to invoke completion (without a space) a Null Pointer Exception occurs and Ammonite exits.

For example:

Loading...
Welcome to the Ammonite Repl 0.4.8
(Scala 2.11.7 Java 1.8.0_65)
matt-matt@ defException in thread "main" java.lang.NullPointerException

The full stack trace can be seen in the attached file.
amm-def-tab-npe.txt

[lihaoyi]

This wasn't actually fixed it seems.

[edwardsmatt]

Interesting, when running head using sbt shell/test:run or repl/run def<tab> doesn't result in a NPE for me. Do you have any further instructions on how you're reproducing this so I can follow up?

[lihaoyi]

I ran the standalone distribution https://github.com/lihaoyi/Ammonite/releases/tag/0.4.9, which should have your things in it because I merged your stuff earlier? Unless I screwed it up...

[edwardsmatt]

No worries, I just checked the source for that standalone distribution and the fix isn't in there. So I suppose it just wasn't included in the distribution. See the diff:

git diff 0.4.9..HEAD

diff --git a/repl/src/main/scala/ammonite/repl/interp/Pressy.scala b/repl/src/main/scala/ammonite/repl/interp/Pressy.scala
index b94183f..b8db3fb 100644
--- a/repl/src/main/scala/ammonite/repl/interp/Pressy.scala
+++ b/repl/src/main/scala/ammonite/repl/interp/Pressy.scala
@@ -203,27 +212,29 @@ object Pressy {
     def complete(snippetIndex: Int, previousImports: String, snippet: String) = {
       val prefix = previousImports + "\nobject AutocompleteWrapper{\n"
       val suffix = "\n}"
-      val allCode =  prefix + snippet + suffix
+      val allCode = prefix + snippet + suffix
       val index = snippetIndex + prefix.length
       if (cachedPressy == null) cachedPressy = initPressy

       val pressy = cachedPressy
       val currentFile = new BatchSourceFile(
         Compiler.makeFile(allCode.getBytes, name = "Current.scala"),
-        allCode
-      )
+        allCode)

       val r = new Response[Unit]
       pressy.askReload(List(currentFile), r)
       r.get.fold(x => x, e => throw e)

-      val run = new Run(pressy, currentFile, allCode, index)
+      val run = Try(new Run(pressy, currentFile, allCode, index))

-      val (i, all) = run.prefixed
+      val (i, all): (Int, Seq[(String, Option[String])]) = run match {
+        case Success(runSuccess) => runSuccess.prefixed
+        case Failure(throwable) => (0, Seq.empty)
+      }

-      val allNames = all.collect{ case (name, None) => name}.sorted.distinct
+      val allNames = all.collect { case (name, None) => name }.sorted.distinct

-      val signatures = all.collect{ case (name, Some(defn)) => defn }.sorted.distinct
+      val signatures = all.collect { case (name, Some(defn)) => defn }.sorted.distinct

       (i - prefix.length, allNames, signatures)
     }

(I thought I was going insane), because I reproduced it with a failing test before I fixed it 👍

It also appears the tests weren't included:

diff --git a/repl/src/test/scala/ammonite/repl/AutocompleteTests.scala b/repl/src/test/scala/ammonite/repl/AutocompleteTests.scala
index 999fc42..efdf7d4 100644
--- a/repl/src/test/scala/ammonite/repl/AutocompleteTests.scala
+++ b/repl/src/test/scala/ammonite/repl/AutocompleteTests.scala
@@ -132,6 +132,8 @@ object AutocompleteTests extends TestSuite{
             "def >(x: Byte): Boolean"
           ) ^
         )
+
+
         // https://issues.scala-lang.org/browse/SI-9153
         //
         //      complete("""val x = 123; x + x.m<caret>""",
@@ -145,6 +147,14 @@ object AutocompleteTests extends TestSuite{
         //      complete("""Seq(1, 2, 3).map(_.co<caret>mpa)""", compares ^)
         //      complete("""Seq(1, 2, 3).map(_.<caret>compa)""", compares, ^)
       }
+      'defTab {
+        //Assert no NullPointerException was thrown. Does not verify any completions.
+        complete( """def<caret>""", Set.empty -- _)
+      }
+      'Array {
+        //Test around https://github.com/lihaoyi/Ammonite/issues/252
+        complete("""new Array<caret>""", Set() ^)
+      }
     }
   }
 }

[lihaoyi]

Ah ok, I must have borked the release then, maybe I forgot to pull after merging your stuff on the website. It'll go out next release then =)

[edwardsmatt]

👍 👍