Loading...

XML

Word

Printable

Details

Type: Bug
Resolution: Done
Priority: Not Evaluated
Fix Version/s: Qt Creator 4.10.1
Affects Version/s: Qt Creator 4.9.2
Component/s: Debugger
Labels:
None

Platform/s:

Linux/X11
Commits:
a6d3101207901172ddab3593dbd500d89d799128

Description

Qt Creator hangs when I have debugging helpers enabled and I reach code containing a local variable with a rather complex type (template instantiation of a boost::multi_index_container).

When this happens I need to kill gdb to get back control over Qt Creator.

I did some digging and could track (part of) the problem to the code that strips the template parameters from the typename in the method 'stripNamespaceFromType()' in share/qtcreator/debugger/dumper.py (around line 1223). It appears that, for some reason, the typename passed in is truncated and the <> pairs that are searched for and stripped are no longer balanced. In my particular case, I see the following chopped off typename upon entering the method:

------------------
STRIPPING typename: (len 2075):
boost::multi_index::detail::header_holder<std::allocator_traits<boost::detail::allocator::compliant_allocator_rebind_to<std::allocator<CDiaLoadCase *>, boost::multi_index::detail::multi_index_node_type<CDiaLoadCase *, boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::tag<mc::name, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na>, mc::NameKeyExtractor<CDiaLoadCase>, mc::qHashAdapter<QString>, boost::mpl::na>, boost::multi_index::hashed_unique<boost::multi_index::tag<mc::userid, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na>, mc::UserIdKeyExtractor<CDiaLoadCase>, UserIdHash, boost::mpl::na>, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na>, std::allocator<CDiaLoadCase *> >::type>::type>::pointer, boost::multi_index::multi_index_container<CDiaLoadCase *, boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::tag<mc::name, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na, boost::mpl::na>, mc::NameKeyExtractor<CDiaLoadCase>, mc::qHashAdapter<QString>, boost::mpl::na>, boost::multi_index::hashed_unique<boost::mu

This is the code of the relevant method in dumper.py:

    def stripNamespaceFromType(self, typeName):
        ns = self.qtNamespace()
        if len(ns) > 0 and typeName.startswith(ns):
            typeName = typeName[len(ns):]
        pos = typeName.find('<')
        # FIXME: make it recognize  foo<A>::bar<B>::iterator?
        while pos != -1:
            pos1 = typeName.rfind('>', pos)
            typeName = typeName[0:pos] + typeName[pos1+1:]
            pos = typeName.find('<')
        return typeName

In the case above, after the first run though the loop the unterminated '<' at the end is found, causing the loop to continue and pos1 to become -1 as there is no terminating '>' after pos. The whole typeName is then appended again (as pos1+1 is 0, typeName[0:] is appended).

I did not investigate why the typename that is passed in is truncated (which could be considered the root cause).

In the mean time, I have patched the routine as below to make it more robust against unbalanced template argument braces ('<>').

    def stripNamespaceFromType(self, typeName):
        ns = self.qtNamespace()
        if len(ns) > 0 and typeName.startswith(ns):
            typeName = typeName[len(ns):]
        # warn( 'stripping %s' % typeName )
        lvl = 0
        pos = None
        stripChunks = []
        sz = len(typeName)
        for index in range(0, sz):
            s = typeName[index]
            if s == '<':
                lvl += 1
                if lvl == 1:
                    pos = index
                continue
            elif s == '>':
                lvl -= 1
                if lvl < 0 :
                    error( "unbalanced! @index %d" % index )
                if lvl == 0:
                    stripChunks.append( (pos, index+1) )
        if lvl != 0:
            error( "unbalanced at end of expression" )
        for (f,l) in reversed( stripChunks ):
            typeName = typeName[:f] + typeName[l:]
        return typeName