Review Request 118238: Get the top-level context associated with a QML module

[Denis Steckelmacher]

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I have more information about the crash of the unit tests : the crash always happens when the testsuite is about to finish, and enabling the debug messages of kdevplatform allowed me to get this message:

KDevelop::DUChainPrivate::removeDocumentChainFromMemory: removed a top-context that was reference-counted: "file:///usr/share/kde4/apps/kdevqmljssupport/qmlplugins/QtQuick.qml" 7

In fact, the TopDUContext of QtQuick.qml is referenced by an unit test that imports QtQuick, and by the file itself. If the context is removed while still being used, then any call to openDeclaration (that calls Declaration::setContext, that calls Context::topContext) will crash.

How can I specify that I don't want this TopDUContext to be removed before it is not used anymore? I import this context in the test case by using addImportedParentContext, but there is a comment in addImportedParentContext that says "Be sure to have set the text location first, so that the chain is sorted correctly.". Can this be related to my problem, and what is the standard way of importing a context?

- Denis Steckelmacher


On May 21, 2014, 2:40 p.m., Denis Steckelmacher wrote:
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> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/118238/
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> 
> (Updated May 21, 2014, 2:40 p.m.)
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> 
> Review request for KDevelop.
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> Repository: kdev-qmljs
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> Description
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> This patch adds a method that returns the top-level DUContext associated with a QML plugin. It uses KStandardDirs to get the plugin.qmltypes file associated with the module (these files are installed by the plugin in KDE_DATA/kdevqmljssupport/qmlplugins/Module.qml), and then schedules a parse job for the file. If the file has already been parsed, then its top level context is returned. This method will be used to implement import statements. The module files and the complete support for import statements can be found in the "import_statements" of kde:scratch/dsteckelmacher.
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> Diffs
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>   duchain/parsesession.h 0facef4 
>   duchain/parsesession.cpp 998e5b0 
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> Diff: https://git.reviewboard.kde.org/r/118238/diff/
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> Testing
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> This patch cannot be tested as the method is not yet called, but the support for import statements is already implemented in my kde:scratch/dsteckelmacher repository. Import statements work right in KDevelop, but the unit tests segfault when they have to parse a file containing an import. The crash always happens in an openDeclaration() or currentDeclaration() call, and if I comment the faulting call, another one will crash. The crash does not happen anymore if I remove the calls to "bgparser->addDocument" added in this patch, and does not happen in a complete KDevelop instance.
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> I'm therefore wondering how the background parser can interact with openDeclaration(). I've checked and a DUChainReadLock or a DUChainWriteLock is always held when openDeclaration() is called, but maybe there are other locks that may be needed. I turn to more advanced KDevelop developers on this matter.
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> Thanks,
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> Denis Steckelmacher
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>

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