Fix compiler plugin instance duplication

[tkroman]

Which was caused by the presence of both normal and source jars on the classpath and led to behaviour like this:

@ interp.load.plugin.ivy("org.scalamacros" % "paradise_2.11.7" % "2.1.0")

@ var x = 1
cmd2.sc:2: both org.scalamacros.paradise.typechecker.AnalyzerPlugins$MacroPlugin$@4e3931 and org.scalamacros.paradise.typechecker.AnalyzerPlugins$MacroPlugin$@409e0e69 want to enter a symbol for this tree
package $sess
        ^
scala.reflect.internal.Types$TypeError: both org.scalamacros.paradise.typechecker.AnalyzerPlugins$MacroPlugin$@4e3931 and org.scalamacros.paradise.typechecker.AnalyzerPlugins$MacroPlugin$@409e0e69 want to enter a symbol for this tree
  scala.tools.nsc.typechecker.Contexts$ThrowingReporter.handleError(Contexts.scala:1402)
  scala.tools.nsc.typechecker.Contexts$ContextReporter.info0(Contexts.scala:1297)
  scala.tools.nsc.typechecker.Contexts$ContextReporter.info0(Contexts.scala:1250)
  scala.reflect.internal.Reporter.error(Reporting.scala:82)
  scala.tools.nsc.typechecker.Contexts$Context.error(Contexts.scala:577)
  scala.tools.nsc.typechecker.AnalyzerPlugins$class.invoke(AnalyzerPlugins.scala:373)
  scala.tools.nsc.typechecker.AnalyzerPlugins$class.pluginsEnterSym(AnalyzerPlugins.scala:423)
  ammonite.runtime.CompilerCompatibility$$anon$2.pluginsEnterSym(CompilerCompatibility.scala:10)
  scala.tools.nsc.typechecker.Namers$Namer.enterSym(Namers.scala:275)
  scala.tools.nsc.typechecker.Analyzer$namerFactory$$anon$1.apply(Analyzer.scala:43)
  scala.tools.nsc.Global$GlobalPhase$$anonfun$applyPhase$1.apply$mcV$sp(Global.scala:440)
  scala.tools.nsc.Global$GlobalPhase.withCurrentUnit(Global.scala:431)
  scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:440)
  scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:398)
  scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:398)
  scala.collection.Iterator$class.foreach(Iterator.scala:893)
  scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
  scala.tools.nsc.Global$GlobalPhase.run(Global.scala:398)
  scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1501)
  scala.tools.nsc.Global$Run.compileUnits(Global.scala:1486)
  scala.tools.nsc.Global$Run.compileSources(Global.scala:1481)
  scala.tools.nsc.Global$Run.compileFiles(Global.scala:1571)
  ammonite.runtime.Compiler$$anon$4.compile(Compiler.scala:284)
  ammonite.runtime.Interpreter.compileClass(Interpreter.scala:258)
  ammonite.runtime.Interpreter$$anonfun$evaluateLine$2.apply(Interpreter.scala:278)
  ammonite.runtime.Interpreter$$anonfun$evaluateLine$2.apply(Interpreter.scala:277)
  ammonite.util.Catching.flatMap(Res.scala:108)
  ammonite.runtime.Interpreter.evaluateLine(Interpreter.scala:277)
  ammonite.runtime.Interpreter$$anonfun$processLine$2$$anonfun$apply$10$$anonfun$apply$12.apply(Interpreter.scala:233)
  ammonite.runtime.Interpreter$$anonfun$processLine$2$$anonfun$apply$10$$anonfun$apply$12.apply(Interpreter.scala:223)
  ammonite.util.Res$Success.flatMap(Res.scala:57)
  ammonite.runtime.Interpreter$$anonfun$processLine$2$$anonfun$apply$10.apply(Interpreter.scala:223)
  ammonite.runtime.Interpreter$$anonfun$processLine$2$$anonfun$apply$10.apply(Interpreter.scala:213)
  ammonite.util.Res$Success.flatMap(Res.scala:57)
  ammonite.runtime.Interpreter$$anonfun$processLine$2.apply(Interpreter.scala:213)
  ammonite.runtime.Interpreter$$anonfun$processLine$2.apply(Interpreter.scala:209)
  ammonite.util.Catching.flatMap(Res.scala:108)
  ammonite.runtime.Interpreter.processLine(Interpreter.scala:209)
  ammonite.repl.Repl$$anonfun$action$4$$anonfun$apply$2.apply(Repl.scala:88)
  ammonite.repl.Repl$$anonfun$action$4$$anonfun$apply$2.apply(Repl.scala:87)
  ammonite.repl.Scoped$$anonfun$flatMap$1.apply(Signaller.scala:44)
  ammonite.repl.Signaller.apply(Signaller.scala:29)
  ammonite.repl.Scoped$class.flatMap(Signaller.scala:44)
  ammonite.repl.Signaller.flatMap(Signaller.scala:11)
  ammonite.repl.Repl$$anonfun$action$4.apply(Repl.scala:87)
  ammonite.repl.Repl$$anonfun$action$4.apply(Repl.scala:74)
  ammonite.util.Res$Success.flatMap(Res.scala:57)
  ammonite.repl.Repl.action(Repl.scala:74)
  ammonite.repl.Repl.loop$1(Repl.scala:98)
  ammonite.repl.Repl.run(Repl.scala:117)
  ammonite.Main.run(Main.scala:108)
  ammonite.Main$$anonfun$main$1$$anonfun$apply$1.apply(Main.scala:249)
  ammonite.Main$.ammonite$Main$$ifContinually$1(Main.scala:228)
  ammonite.Main$$anonfun$main$1.apply(Main.scala:230)
  ammonite.Main$$anonfun$main$1.apply(Main.scala:230)
  scala.Option.foreach(Option.scala:257)
  ammonite.Main$.main(Main.scala:230)
  ammonite.Main.main(Main.scala:-1)
Something unexpected went wrong =(

[tkroman]

I deleted the test since it was obviously bogus (since there is no way to specify classifiers like withSources() (or at least I don't know any)).
I don't know if that means anything, but a) I'm sure that this fixes my issue; b) it doesn't break anything and c) in the end it's up to you to decide :)

[lihaoyi]

I don't understand; if it fixes your issue, can't you put the console trace of your issue-repro in the test?

[tkroman]

@lihaoyi oh, I didn't realise that loading the foo dependency not only causes the foo.jar, but also the foo-sources.jar to be loaded. But I checked with a clean cache and yes it does. This is weird. I returned the test.

[tkroman]

Whaaaat. The JVM crashed. I'm not sure that's my fault. Can you trigger a rebuild?

[Ammonite-Bot]

ah sure lemme do that when i get back to my computer

On Wednesday, 7 September 2016, Roman Tkalenko notifications@github.com
wrote:

Whaaaat. The JVM crashed. I'm not sure that's my fault. Can you trigger a
rebuild?

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
#461 (comment), or mute
the thread
https://github.com/notifications/unsubscribe-auth/ATpwjIcbFjrmmYnicPGd1OAljoydruOTks5qnfuagaJpZM4J1NoR
.

[lihaoyi]

@tkroman The tests pass and I can repro locally. Could you explain in a bit more detail why the status quo has this problem, and why this fixes it? It's not clear to me reading the code

[tkroman]

When you load the macro-paradise plugin, 2 jars containing the scalac-plugin.xml are downloaded, e.g. paradise_2.11.8-2.1.0.jar and paradise_2.11.8-2.1.0-sources.jar.
Both jars are considered to be on the pluginClassloader's classpath, hence they both will be detected as plugin-containing ones. Since there are no equality checks (currently), the pair ("macro-paradise", "class of macro-paradise plugin") is stored in the plugins list 2 times.
Plugins are stored in a non-unique collection, so it's possible to add 2 instances of the same plugin.
During the phase of plugins analysis (scala.tools.nsc.typechecker.AnalyzerPlugins#invoke) there is a check that (as far as I understood) no two plugins can simultaneously enter the symbol at the same position at the same time (scala.tools.nsc.typechecker.AnalyzerPlugins#pluginsEnterSym). Since the 2 instances we have are actually the same plugin, it's obvious we'll get this error here.

To be completely honest, I'm looking at all this stuff from a beginner's point of view. I just did what seemed logical after reading the code where the exception happened. The only guess I had to do was about having more than one jar on the classpath, and that's easily checked with the debugger.

[lihaoyi]

Ok sounds reasonable, thanks!

[lihaoyi]

@tkroman This is available in the latest unstable version COMMIT-849e5e7 http://www.lihaoyi.com/Ammonite/#UnstableVersions

[tkroman]

@lihaoyi awesome, thanks!