Support forward reference from annotation argument to member of the annotated class.

[scabug]

With Scalac 2.10, the use of any objects, class or method annotaded with the com.unboundid.util.ThreadSafetyLevel leads to java.lang.AssertionError.

For example, the following file Test.scala:

import com.unboundid.ldap.sdk.Entry

object Test extends App {

  val foo = new Entry("plop")

}

Leads to :

% scalac -classpath ./lib/unboundid-ldapsdk-2.3.1.jar src/Test.scala
warning: Caught: java.lang.AssertionError: assertion failed: 
     while compiling: src/Test.scala
        during phase: global=typer, atPhase=parser
     library version: version 2.10.0
    compiler version: version 2.10.0
  reconstructed args: -classpath ./lib/unboundid-ldapsdk-2.3.1.jar

  last tree to typer: Ident(Entry)
              symbol: <none> (flags: )
   symbol definition: <none>
       symbol owners: 
      context owners: value foo -> object Test -> package <empty>

== Enclosing template or block ==

Template( // val <local Test>: <notype> in object Test
  "App" // parents
  ValDef(
    private
    "_"
    <tpt>
    <empty>
  )
  // 2 statements
  DefDef( // def <init>: <?> in object Test
    <method>
    "<init>"
    []
    List(Nil)
    <tpt>
    Block(
      Apply(
        super."<init>"
        Nil
      )
      ()
    )
  )
  ValDef( // private[this] val foo: <?> in object Test
    private <local> <locked>
    "foo"
    <tpt>
    Apply(
      new Entry."<init>"
      "plop"
    )
  )
)

com.unboundid.util.ThreadSafetyLevel while parsing annotations in ./lib/unboundid-ldapsdk-2.3.1.jar(com/unboundid/util/ThreadSafetyLevel.class)
one warning found

ThreadSafety.java source here: http://ldap-sdk.svn.sourceforge.net/viewvc/ldap-sdk/trunk/src/com/unboundid/util/ThreadSafety.java?revision=410&view=markup

Link to unboundid-ldapsdk-2.3.1.jar: https://www.unboundid.com/products/ldap-sdk/files/unboundid-ldapsdk-2.3.1-se.zip

That seems to be linked to the following comment: https://github.com/scala/scala/blob/master/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala#L1033

// We want to be robust when annotations are unavailable, so the very least
// we can do is warn the user about the exception
// There was a reference to ticket 1135, but that is outdated: a reference to a class not on
// the classpath would *not* end up here. A class not found is signaled
// with a `FatalError` exception, handled above. Here you'd end up after a NPE (for example),
// and that should never be swallowed silently.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-7014?orig=1 Reporter: Francois Armand (fanf) Affected Versions: 2.10.0, 2.10.2 See #7551

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Sebastian Meßmer (smessmer) said: same bug here. It's only a warning, but it's a disturbing one with a lot of output.

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Mariusz Sakowski (sakfa) said: Same thing here, major issue for me because Play Framework 2.0 gets confused when displaying normal compilation errors (displays this warning instead)

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Francois Armand (fanf) said: Since Scala 2.10.2, that bug simply terminate the build, so basically, I can't use Scala 2.10.2 on my project. I would qualify that one as blocker now - I'm stuck with Scala 2.10.1.

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@adriaanm said: sorry to hear it -- looking into it test files here: https://github.com/adriaanm/scala/tree/ticket-7014

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@gkossakowski said: Assigning to Adriaan who seemed to look into this. Feel free to unassign if you don't plan to work on this ticket.

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Francois Armand (fanf) said (edited on Jul 16, 2013 11:47:37 AM UTC): I just got eaten with the update to Scala-IDE 3.0.1 which uses Scala 2.10.2, and so is not usable on our project. So, that bug is starting to be really annoying.

All in all, I prefered the past behaviour, with hundreds of assert error lines in the log. Our build output were crap, but actually could build the project...

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Sonnenschein (sonnenschein) said: I've also voted for this issue to be resolved.

For the time being, I decided to package my single layer dealing with LDAP into a separate JAR which I than use as an unmanaged library. Since the rest doesn't need a dependency to UnboundID-SDK, I can keep out the annoying noise from the rest.

Peter

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Jun Yamog (jkyamog) said: Same here. We are using unboundid in our play app. So eclipse is reporting SBT is crashing. We haven't upgraded our play project, so command line compiling is still working.

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@adriaanm said: Looks like RUNTIME retention annotations aren't supported: https://github.com/scala/scala/blob/2.10.x/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala#L911

Not sure what we can do for this in 2.10, as this is now a maintenance release. Happy to take PRs. I'll still see if I can avoid the crash and continue with a dummy or something.

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@adriaanm said: I jumped to conclusions: the problem is the forward reference from the annotation argument to a member of the annotated class. We won't be able to fix this for 2.10.3, but I'll submit a PR that turns the crash into a warning. You should be able to compile normally, I assume.

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@adriaanm said (edited on Aug 13, 2013 10:18:44 PM UTC): Fix for crasher: https://github.com/scala/scala/pull/2829 (Don't close on merging.)

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@retronym said: See also #7551 / https://github.com/retronym/scala/compare/ticket;7551

commit b545e410e072600b1dc77c6b8536eb3c22cd657a
Author: Jason Zaugg <jzaugg@gmail.com>
Date:   Tue Jun 4 09:32:36 2013 +0200

    WIP SI-7551 Ignore class file parser cycles in annotations

    But should we be parsing runtime visible annotations other than
    ScalaSignature at all?

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Francois Armand (fanf) said: I can confirm that the workaround allows to build our project again, and avoid displaying horrible debug information on the stdout.

Thanks!

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Hendy Irawan (ceefour) said: +1 for this