Bugzilla – Full Text Bug Listing
| Summary: | BacktrackingSemanticSequencer can take forvever. | ||||||
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| Product: | [Modeling] TMF | Reporter: | Ed Willink <ed> | ||||
| Component: | Xtext | Assignee: | Project Inbox <tmf.xtext-inbox> | ||||
| Status: | CLOSED FIXED | QA Contact: | |||||
| Severity: | major | ||||||
| Priority: | P3 | CC: | moritz.eysholdt, sebastian.zarnekow | ||||
| Version: | 2.0.0 | ||||||
| Target Milestone: | --- | ||||||
| Hardware: | PC | ||||||
| OS: | Windows Vista | ||||||
| Whiteboard: | |||||||
| Bug Depends on: | |||||||
| Bug Blocks: | 362517 | ||||||
| Attachments: |
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Description
Ed Willink
Ping. Are there any plans to fix this. Not being able to handle large models is a problem for me. I'm considering reverting to the old serializer, which will be painful because I'll have to undo the cleanup that the new architecture enabled me to do. I'll take a look at it. Are these the sources you're working with? http://git.eclipse.org/c/mdt/org.eclipse.ocl.git/tree/examples (In reply to comment #2) > I'll take a look at it. Are these the sources you're working with? > http://git.eclipse.org/c/mdt/org.eclipse.ocl.git/tree/examples Yes. I appreciate working with a large body of someone else's code is not much fun which is why I looked to try to provide a more modest repro, but found that I could make a variety of different 25% trims to Ecore.ecore and the problem went away. Further investigation revealed suspicious problems with ordering, which at least offer optimisations even if they aren't actually the bug. Any news? Bug 361649 is causing me trouble too. Any news. Problem is still present in a-just-before M6 build. It's really disappointing that the ability to load Ecore.ecore or UML.ecore was present in Indigo and not in Juno. Moritz, I have an example looping predictably. It keeps creating a new FollowerSorter that is identical to the previous one because TraceItem.getNextGrammarElement() returns null. I'll look for you on the itemis stand at about 8:45 so that you can step through it. Created attachment 213290 [details] Exatr debug To reproduce the problem: Install 4.2M6 modeling EPP. Install Xtext, OCL Examples and Editors [and MWE2, Acceleo, Subversive, EMF Compare 1.3M5, EGIT 2.0.0 nightly] Import org.eclipse.xtext as a Plugin with Sources and use the instrumented BacktrackingSemanticSequencer.java attached. Checkout the http://git.eclipse.org/c/mdt/org.eclipse.ocl.git repo and the XtextSerializationInvestigation branch. Run the org.eclipse.ocl.examples.xtext.tests (standalone) launch config Kill it once a test has started (all tests preceding testSerialize_Ecore should pass). Browse to org.eclipse.ocl.examples.test.xtext.SerializeTests (about seven from the bottom). Open it and select testSerialize_Ecore. Running testSerialize_Ecore shows no progress with the Console showing... FollowerSorter 65177 EObject: RootPackageCS.ownedNestedPackage[0]->PackageCS'ecore'.ownedType[2]->ClassCS'EClass' Values: name(1), ownedConstraint(8), ownedSuperType(1), ownedOperation(9), ownedProperty(16) null FollowerSorter 65178 EObject: RootPackageCS.ownedNestedPackage[0]->PackageCS'ecore'.ownedType[2]->ClassCS'EClass' Values: name(1), ownedConstraint(8), ownedSuperType(1), ownedOperation(9), ownedProperty(16) null To debug set a breakpoint in BacktrackingSemanticSequencer.FollowerSorter in the counter > 310 branch. (In reply to comment #7) > Checkout the http://git.eclipse.org/c/mdt/org.eclipse.ocl.git repo and the > XtextSerializationInvestigation branch. Import the following plugins from the GIT workspace examples/org.eclipse.ocl.examples.codegen examples/org.eclipse.ocl.examples.domain examples/org.eclipse.ocl.examples.library examples/org.eclipse.ocl.examples.pivot examples/org.eclipse.ocl.examples.ui examples/org.eclipse.ocl.examples.xtext.* tests/org.eclipse.ocl.examples.xtext.tests Moritz, is this the one that you fixed, recently? Moritz, following out partial investigation at EclipseCon, have you got everything you need to investigate this? (In reply to comment #9) > Moritz, is this the one that you fixed, recently? no, that fix did not yet solve the problem reported in this ticket. (In reply to comment #10) > Moritz, following out partial investigation at EclipseCon, have you got > everything you need to investigate this? yes, Ed, I can reproduce this now on my machine. Hi Ed, i've implemented a fix for this issues. See http://git.eclipse.org/c/tmf/org.eclipse.xtext.git/commit/?id=ba26c7a89e55a1f2a4a517d1493c04679b5db155 Now the test org.eclipse.ocl.examples.test.xtext.SerializeTests.testSerialize_Ecore() fails with a model comparison error in org.eclipse.ocl.examples.xtext.tests.XtextTestCase.assertSameModel(Resource, Resource, Map<String, Object>) To compare models, you might want to use String expected = EmfFormatter.objToStr( expectedResource.getContents().get(0)); String actual = EmfFormatter.objToStr( actualResource.getContents().get(0)); Assert.assertEquals(expected, actual); because in case of a failure, you can use JDT-Junit's excellent text comparison dialog to inspect the differences. The problem was caused by rule ClassCS returns base::ClassCS: qualifier+='abstract'? 'class' name=UnrestrictedName (ownedTemplateSignature=TemplateSignatureCS)? ('extends' ownedSuperType+=TypedRefCS (',' ownedSuperType+=TypedRefCS)*)? (':' instanceClassName=SINGLE_QUOTED_STRING)? ('{' qualifier+='interface' '}')? ( ('{' (ownedAnnotation+=AnnotationElementCS | ownedOperation+=OperationCS | ownedProperty+=StructuralFeatureCS | ownedConstraint+=InvariantConstraintCS)* '}') | ';' ) ; in your grammar. The optional elements at the beginning and the multiple-alternative at the end led to many possible paths the backtracking algorithm could take. It spent too much time with trying the wrong paths. I assume the algorithm would have terminated at some point, but neuter of use was willing to wait long enough ;) My fix prevents the backtracking algorithm to try paths which can not lead to success. Such paths are paths that have no possibility of consuming at least one of the remaining values from an EObject. They can not consume a value because the path does not include a grammatical assignment for the EStructuralFeature the value resides in. Ed, could you verify if the fix works for you? (In reply to comment #12) > Ed, could you verify if the fix works for you? Thanks. What an easy fix! The N-build works for me; now I just have a little bit of my own bit rot to repair. ok, then I consider this fixed. Please reopen if I missed something. (In reply to comment #12) > To compare models, you might want to use > String expected = EmfFormatter.objToStr( ... > because in case of a failure, you can use JDT-Junit's excellent text comparison > dialog to inspect the differences. Nice. listToStr() is even better. |