Memory leak from list<CloneList *>

[Scott Kostyshak]

On Tue, Feb 18, 2020 at 07:33:39PM -0500, Richard Kimberly Heck wrote:
> On 2/18/20 6:07 PM, Scott Kostyshak wrote:
> > Valgrind gave me the following error:
> >
> >   ==732== 112 (72 direct, 40 indirect) bytes in 1 blocks are definitely lost in loss record 5,165 of 5,862
> >   ==732==    at 0x483AE63: operator new(unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
> >   ==732==    by 0x103A62D: lyx::Buffer::cloneBufferOnly() const (Buffer.cpp:661)
> >   ==732==    by 0x11E583C: lyx::(anonymous namespace)::copyToTempBuffer(lyx::ParagraphList const&, std::shared_ptr<lyx::DocumentClass const>) (CutAndPaste.cpp:582)
> >   ==732==    by 0x11E5C6A: lyx::(anonymous namespace)::putClipboard(lyx::ParagraphList const&, std::shared_ptr<lyx::DocumentClass const>, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > const&, lyx::BufferParams) (CutAndPaste.cpp:613)
> >   ==732==    by 0x11E910B: lyx::cap::copySelection(lyx::Cursor const&, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > const&) (CutAndPaste.cpp:1123)
> >   ==732==    by 0x11E84F8: lyx::cap::copySelection(lyx::Cursor const&) (CutAndPaste.cpp:1024)
> >   ==732==    by 0x13ECDAB: lyx::Text::dispatch(lyx::Cursor&, lyx::FuncRequest&) (Text3.cpp:1593)
> >   ==732==    by 0x1767E04: lyx::InsetText::doDispatch(lyx::Cursor&, lyx::FuncRequest&) (InsetText.cpp:339)
> >   ==732==    by 0x15FFC39: lyx::Inset::dispatch(lyx::Cursor&, lyx::FuncRequest&) (Inset.cpp:325)
> >   ==732==    by 0x11D1B13: lyx::Cursor::dispatch(lyx::FuncRequest const&) (Cursor.cpp:825)
> >   ==732==    by 0x1816F4F: lyx::frontend::GuiView::dispatchToBufferView(lyx::FuncRequest const&, lyx::DispatchResult&) (GuiView.cpp:3878)
> >   ==732==    by 0x181B959: lyx::frontend::GuiView::dispatch(lyx::FuncRequest const&, lyx::DispatchResult&) (GuiView.cpp:4569)
> >
> > It comes from the following line (Buffer.cpp:661):
> >
> >   cloned_buffers.push_back(new CloneList);
> >
> > Currently cloned_buffers is a list<CloneList *>. Would it make sense to make it a list of *smart* pointers instead? Alternatively we could make a class and then make a custom destructor that would free the CloneLists that the list elements point to?
> 
> This is some kind of thinko, probably on my part. The code at line 549
> was supposed to be cleaning this up, but it actually only removes the
> entry from the list.
> 
> If it works to make it a smart pointer of some kind, then that would be
> simplest. But I think we could just do something like:
> 
> else {
>     delete(*it);
>     cloned_buffers.erase(it);
> }

Ah that makes sense.

> I should learn how to use valgrind. Then I could solve these problems
> myself....

The hard part (for me) is interpreting the results. Well, actually the
hardest part is waiting because LyX is very slow when run under
valgrind. Probably there are some options to mess with to speed things
up a bit. The command I run is this:

  valgrind --leak-check=full --track-origins=yes --log-file=valgrind.log ~/lyxbuilds/master/CMakeBuild/bin/lyx -userdir ~/lyxbuilds/master/user-dir

Scott
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