D19532: Don't crash when no contexts are present

[Dāvis Mosāns]

davispuh added a comment.


  Creating a syntax highlighting file with few unclosed tags made Kate to crash. No matter how malformed XML it loads, editor should never crash as it can cause loss of unsaved work.
  
  Crash is caused by
  
    Context* DefinitionData::initialContext() const
    {
        Q_ASSERT(!contexts.isEmpty());
        return contexts.first();
    }
  
  which is called from
  
    State AbstractHighlighter::highlightLine(const QString& text, const State &state)
    {
        Q_D(AbstractHighlighter);
    
        // verify definition, deal with no highlighting being enabled
        d->ensureDefinitionLoaded();
        if (!d->m_definition.isValid()) {
            applyFormat(0, text.size(), Format());
            return State();
        }
    
        // verify/initialize state
        auto defData = DefinitionData::get(d->m_definition);
        auto newState = state;
        auto stateData = StateData::get(newState);
        const DefinitionRef currentDefRef(d->m_definition);
        if (!stateData->isEmpty() && (stateData->m_defRef != currentDefRef)) {
            qCDebug(Log) << "Got invalid state, resetting.";
            stateData->clear();
        }
        if (stateData->isEmpty()) {
            stateData->push(defData->initialContext(), QStringList());
            stateData->m_defRef = currentDefRef;
        }
  
  here's the backtrace itself
  
    #0  0x00007fe9863b4d7f in raise () from /usr/lib/libc.so.6
    #1  0x00007fe98639f672 in abort () from /usr/lib/libc.so.6
    #2  0x00007fe9867567fc in QMessageLogger::fatal(char const*, ...) const () from /usr/lib/libQt5Core.so.5
    #3  0x00007fe986755c28 in qt_assert(char const*, char const*, int) () from /usr/lib/libQt5Core.so.5
    #4  0x00007fe985e966f3 in KSyntaxHighlighting::DefinitionData::initialContext (this=<optimized out>) from /usr/lib/libKF5SyntaxHighlighting.so.5
    #5  0x00007fe985e981c2 in KSyntaxHighlighting::AbstractHighlighter::highlightLine (this=this at entry=0x55c256cba090, text=..., state=...)
        at /usr/include/qt/QtCore/qlist.h:151
    #6  0x00007fe988464b6f in KateHighlighting::doHighlight (this=0x55c256cba090, prevLine=<optimized out>, textLine=0x55c25690cb70, 
        nextLine=nextLine at entry=0x55c2569b7420, ctxChanged=@0x7ffe2d101ae3: false, tabWidth=8)
        at /usr/src/debug/ktexteditor/src/buffer/katetextline.h:311
    #7  0x00007fe9883facbd in KateBuffer::doHighlight (invalidate=<optimized out>, endLine=<optimized out>, startLine=<optimized out>, 
        this=0x55c257a097d0) at /usr/src/debug/ktexteditor/src/document/katebuffer.h:203
    #8  KateBuffer::doHighlight (this=0x55c257a097d0, startLine=<optimized out>, endLine=<optimized out>, invalidate=<optimized out>)
        at /usr/src/debug/ktexteditor/src/document/katebuffer.cpp:360
    #9  0x00007fe9883d8cf4 in KTextEditor::DocumentPrivate::kateTextLine (this=0x55c255de2c10, i=0)
        at /usr/src/debug/ktexteditor/src/document/katedocument.cpp:5249
    #10 0x00007fe98844a0a5 in KateLineLayout::textLine (this=0x55c256b75980, reloadForce=reloadForce at entry=false)
        at /usr/src/debug/ktexteditor/src/render/katelinelayout.cpp:79
    #11 0x00007fe988440350 in KateRenderer::layoutLine (this=0x55c256cef2a0, lineLayout=..., maxwidth=-1, cacheLayout=<optimized out>)
        at /usr/src/debug/ktexteditor/src/render/katerenderer.cpp:1021
    #12 0x00007fe988444591 in KateLayoutCache::line (this=0x55c256cee360, realLine=0, virtualLine=<optimized out>)
        at /usr/include/c++/8.2.1/bits/atomic_base.h:295
    #13 0x00007fe988446a6a in KateLayoutCache::updateViewCache (this=this at entry=0x55c256cee360, startPos=..., 
        newViewLineCount=newViewLineCount at entry=40, viewLinesScrolled=viewLinesScrolled at entry=0)
        at /usr/src/debug/ktexteditor/src/render/katelayoutcache.cpp:242
    #14 0x00007fe98848916b in KateViewInternal::updateView (this=0x55c255f63a50, changed=true, viewLinesScrolled=viewLinesScrolled at entry=0)
        at /usr/src/debug/ktexteditor/src/include/ktexteditor/cursor.h:98
    #15 0x00007fe98846f3a7 in KTextEditor::ViewPrivate::updateView (this=0x55c255f30f40, changed=<optimized out>)
        at /usr/src/debug/ktexteditor/src/view/kateview.cpp:2047
    #16 0x00007fe9883dc786 in KTextEditor::DocumentPrivate::makeAttribs (this=this at entry=0x55c255de2c10, needInvalidate=needInvalidate at entry=false)
        at /usr/src/debug/ktexteditor/src/document/katedocument.cpp:2910
    #17 0x00007fe9883dc7fc in KTextEditor::DocumentPrivate::bufferHlChanged (this=0x55c255de2c10)
        at /usr/src/debug/ktexteditor/src/document/katedocument.cpp:1876
    #18 0x00007fe9883faaad in KateBuffer::setHighlight (this=0x55c257a097d0, hlMode=<optimized out>)
        at /usr/src/debug/ktexteditor/src/document/katebuffer.cpp:346
    #19 0x00007fe9883ec4ff in KTextEditor::DocumentPrivate::updateFileType (this=this at entry=0x55c255de2c10, newType=..., user=user at entry=false)
        at /usr/src/debug/ktexteditor/src/document/katedocument.cpp:5061
    #20 0x00007fe9883ef5b4 in KTextEditor::DocumentPrivate::openFile (this=0x55c255de2c10) at /usr/src/debug/ktexteditor/src/utils/kateglobal.h:252
    #21 0x00007fe988281873 in ?? () from /usr/lib/libKF5Parts.so.5
    #22 0x00007fe98828286f in KParts::ReadOnlyPart::openUrl(QUrl const&) () from /usr/lib/libKF5Parts.so.5
    #23 0x00007fe9883debf2 in KTextEditor::DocumentPrivate::openUrl (this=0x55c255de2c10, url=...) at /usr/src/debug/ktexteditor/src/document/katedocument.cpp:2736

REPOSITORY
  R216 Syntax Highlighting

REVISION DETAIL
  https://phabricator.kde.org/D19532

To: davispuh, cullmann, dhaumann, vandenoever
Cc: kwrite-devel, kde-frameworks-devel, domson, michaelh, ngraham, bruns, demsking, cullmann, sars, dhaumann
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