[validation] reconciler throws NPE

[martinlippert]

I tried the latest pre-release in VSCode with a petclinic sample application, hacking some stuff in some classes. Afterwards, I found these exceptions (a bunch of them) on the log of the language server:

12:34:07.710 [pool-4-thread-6] ERROR o.s.i.v.b.j.r.JdtReconciler - 
java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.core.dom.CompilationUnit.accept(org.eclipse.jdt.core.dom.ASTVisitor)" because "cu" is null
	at org.springframework.ide.vscode.boot.java.reconcilers.AnnotationNodeReconciler.reconcile(AnnotationNodeReconciler.java:82)
	at org.springframework.ide.vscode.boot.java.reconcilers.JdtReconciler.reconcile(JdtReconciler.java:87)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.lambda$handle$0(RewriteCodeActionHandler.java:114)
	at org.springframework.ide.vscode.boot.java.utils.CompilationUnitCache.withCompilationUnit(CompilationUnitCache.java:233)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.handle(RewriteCodeActionHandler.java:109)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.lambda$handle$0(BootJavaCodeActionProvider.java:52)
	at java.base/java.util.stream.ReferencePipeline$7$1.accept(Unknown Source)
	at java.base/java.util.Iterator.forEachRemaining(Unknown Source)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.handle(BootJavaCodeActionProvider.java:57)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.lambda$handle$0(CompositeLanguageServerComponents.java:119)
	at java.base/java.util.Optional.map(Unknown Source)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.handle(CompositeLanguageServerComponents.java:119)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.computeCodeActions(SimpleTextDocumentService.java:471)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.lambda$codeAction$12(SimpleTextDocumentService.java:517)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

There was also a user visible problem happening on the UI, the content-assist was blocked (did not show any proposals anymore, just loading...), but I am not sure whether it is related or not.

Nevertheless, we need to fix this NPE issue, whether it is related to the auto-complete problem or not.

[martinlippert]

It looks like the exception is thrown by all the various reconcilers, I can see the same or a similar exception from all of them, for example:

12:34:07.710 [pool-4-thread-6] ERROR o.s.i.v.b.j.r.JdtReconciler - 
java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.core.dom.CompilationUnit.accept(org.eclipse.jdt.core.dom.ASTVisitor)" because "cu" is null
	at org.springframework.ide.vscode.boot.java.reconcilers.BeanMethodNotPublicReconciler.reconcile(BeanMethodNotPublicReconciler.java:135)
	at org.springframework.ide.vscode.boot.java.reconcilers.JdtReconciler.reconcile(JdtReconciler.java:87)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.lambda$handle$0(RewriteCodeActionHandler.java:114)
	at org.springframework.ide.vscode.boot.java.utils.CompilationUnitCache.withCompilationUnit(CompilationUnitCache.java:233)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.handle(RewriteCodeActionHandler.java:109)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.lambda$handle$0(BootJavaCodeActionProvider.java:52)
	at java.base/java.util.stream.ReferencePipeline$7$1.accept(Unknown Source)
	at java.base/java.util.Iterator.forEachRemaining(Unknown Source)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.handle(BootJavaCodeActionProvider.java:57)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.lambda$handle$0(CompositeLanguageServerComponents.java:119)
	at java.base/java.util.Optional.map(Unknown Source)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.handle(CompositeLanguageServerComponents.java:119)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.computeCodeActions(SimpleTextDocumentService.java:471)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.lambda$codeAction$12(SimpleTextDocumentService.java:517)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

or

12:34:07.711 [pool-4-thread-6] ERROR o.s.i.v.b.j.r.JdtReconciler - 
java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.core.dom.CompilationUnit.getPackage()" because "cu" is null
	at org.springframework.ide.vscode.boot.java.reconcilers.ModulithTypeReferenceViolationReconciler.reconcile(ModulithTypeReferenceViolationReconciler.java:47)
	at org.springframework.ide.vscode.boot.java.reconcilers.JdtReconciler.reconcile(JdtReconciler.java:87)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.lambda$handle$0(RewriteCodeActionHandler.java:114)
	at org.springframework.ide.vscode.boot.java.utils.CompilationUnitCache.withCompilationUnit(CompilationUnitCache.java:233)
	at org.springframework.ide.vscode.boot.java.rewrite.RewriteCodeActionHandler.handle(RewriteCodeActionHandler.java:109)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.lambda$handle$0(BootJavaCodeActionProvider.java:52)
	at java.base/java.util.stream.ReferencePipeline$7$1.accept(Unknown Source)
	at java.base/java.util.Iterator.forEachRemaining(Unknown Source)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.springframework.ide.vscode.boot.java.handlers.BootJavaCodeActionProvider.handle(BootJavaCodeActionProvider.java:57)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.lambda$handle$0(CompositeLanguageServerComponents.java:119)
	at java.base/java.util.Optional.map(Unknown Source)
	at org.springframework.ide.vscode.commons.languageserver.composable.CompositeLanguageServerComponents$3.handle(CompositeLanguageServerComponents.java:119)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.computeCodeActions(SimpleTextDocumentService.java:471)
	at org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService.lambda$codeAction$12(SimpleTextDocumentService.java:517)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

[BoykoAlex]

@martinlippert Wonder if you get the same issues in reconcilers once you restart VSCode/Eclipse...

I have a bad a feeling that what you got into is not an easily reproducible scenario and it has to do something with some issues in CU Cache Java parsing.

[BoykoAlex]

NPE is fixed 862fd9b It was good to fix it indeed. All other paths to the JdtReconciler#reconole(...) method all check for CU not being null before calling.