Aladdin - Scala Bugtracking
[#519] project: compiler priority: high category: bug
submitter assigned to status date submitted
Sean Martin fixed 2006-01-24 19:13:57.0
subject Object initialization breaks separate compilation
code
what happened 
Example:

On an already built compiler, add a non-private member to Typers in Typers.scala. Using the IDE, build the proje\
ct, the following files will be recompiled:


COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Typers.scala
Signature of L/scala/src/compiler/scala/tools/nsc/typechecker/Typers.scala changed, recompile dependent files
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Namers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/TreeGen.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/TailCalls.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Constructors.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/TransMatcher.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/TreeCheckers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Mixin.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/util/Statistics.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Erasure.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/Global.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/SampleTransform.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/UnCurry.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/LambdaLift.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Infer.scala
Signature of L/scala/src/compiler/scala/tools/nsc/typechecker/TreeCheckers.scala changed, recompile dependent fi\
les
Signature of L/scala/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala changed, recompile dependent files
\

Signature of L/scala/src/compiler/scala/tools/nsc/Global.scala changed, recompile dependent files
Signature of L/scala/src/compiler/scala/tools/nsc/transform/Erasure.scala changed, recompile dependent files
COMPILE: L/scala/src/compiler/scala/tools/nsc/Main.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/SequenceMatchers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/ScalaPrimitives.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/RightTracers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Erasure.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/EtaExpansion.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/MainInterpreter.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/Members.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
COMPILE: L/scala/src/compiler/scala/tools/ant/Scalac.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/models/Models.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/TypeKinds.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/OverridingPairs.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/MainTokenMetric.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/ConstantFolder.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/CompilationUnits.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/SubComponent.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/SyntaxAnalyzer.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/PatternNodes.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/models/Signatures.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Codification.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/MetaParser.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Mixin.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/SymblfileParser.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/Autom2.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/Global.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/LeftTracers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/Printers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/CodeFactory.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/AlgebraicMatchers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/SymbolicXMLBuilder.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/WordAutoms.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/Checkers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/Interpreter.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/Pickler.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/MatcherLabels.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/TreeBrowsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/ICodes.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Flatten.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/Trees.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/Transform.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Infer.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/TreePrinters.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/BasicBlocks.scala
Signature of L/scala/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala changed, recompile dependent files
\

Signature of L/scala/src/compiler/scala/tools/nsc/Global.scala changed, recompile dependent files
COMPILE: L/scala/src/compiler/scala/tools/nsc/Main.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/EtaExpansion.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/Members.scala
COMPILE: L/scala/src/compiler/scala/tools/ant/Scalac.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/OverridingPairs.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/MainTokenMetric.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/SyntaxAnalyzer.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/typechecker/Codification.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/symtab/classfile/MetaParser.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/LeftTracers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/backend/icode/Printers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/CodeFactory.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/AlgebraicMatchers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/SymbolicXMLBuilder.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/matching/WordAutoms.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/TreeBrowsers.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
COMPILE: L/scala/src/compiler/scala/tools/nsc/ast/Trees.scala



Note that the compiler performs 4 separate runs because it doesn't recompile a class's dependencies until it det\
ects that the class's signature (composed of non-private members) has changed.

Now execute the resulting compiler and the following initialization will occur:


java.lang.NullPointerException
	at scala.tools.nsc.typechecker.Typers$class.resetTyper(Typers.scala:33)
	at scala.tools.nsc.Global$analyzer$.resetTyper(Global.scala:190)
	at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon1.(Analyzer.scala:37)
	at scala.tools.nsc.typechecker.Analyzer$typerFactory$.newPhase(Analyzer.scala:36)
	at scala.tools.nsc.typechecker.Analyzer$typerFactory$.newPhase(Analyzer.scala:33)
	at scala.tools.nsc.Global$Run$$anonfun2.apply(Global.scala:309)
	at scala.tools.nsc.Global$Run$$anonfun2.apply(Global.scala:307)
	at scala.List.foreach(List.scala:690)
	at scala.tools.nsc.Global$Run.(Global.scala:307)


Now we can try the same experiment using the ant build 5cr1p7-haX0R (after a clean build to get the compiler back in a\
 good state). 


bash-3.00$ ant
Buildfile: build.xml
     [echo] Running SABBUS for Scala-core

init:
     [echo] SABBUS detected a UNIX environnement

setup:

build.locker:

setup.locker:

build:
   [locker] Compiling source file: scala/tools/nsc/typechecker/Typers.scala to /home/mcdirmid/runtime-workspace/\
scala/build/quick/compiler

BUILD SUCCESSFUL
Total time: 17 seconds



The same null pointer exception occurs and a clean build is needed to fix things.
what expected The only way right now to work around this object initialization problem is to fully rebuild the compiler. Instead, object initialization should either be fully compatible with separate compilation, or we should understand when and what should be rebuilt to ensure that null pointer exceptions do not occur. Otherwise, incremental builds cannot be reliably supported. Note that Typers is a mixin, so this may only be a problem with mixins. I've seen this problem before, but only today did I realize what the problem is.
[back to overview]
Changes of this bug report
Sean  edited on  2006-01-24 19:14:40.0
Martin  edited on  2006-01-28 18:53:10.0