Re: [LyX/master] Avoid using a dangling pointer

[Enrico Forestieri]

On Tue, Jun 30, 2015 at 06:55:04PM +0200, Enrico Forestieri wrote:
> commit 305a712bbb1c201416e7bed2d8e6b7362c3aa5d5
> Author: Enrico Forestieri <for...@lyx.org>
> Date:   Tue Jun 30 18:54:19 2015 +0200
> 
>     Avoid using a dangling pointer
>     
>     This can happen when a macro is copied and then the document where
>     it is defined is closed. In this case, the macro survives in the
>     cut stack but the the buffer pointer is dangling.

Richard, this is also needed in stable to avoid a crash that can be
triggered as follows:
1) With instant preview off, load the attached file1.lyx and file2.lyx
2) In file2.lyx, select and copy the math inset, then close file2.lyx
3) Now activate instant preview for math

It might not crash on the first try but eventually will do.
I am also attaching the corresponding patch for stable.

-- 
Enrico

diff --git a/src/mathed/MathMacro.cpp b/src/mathed/MathMacro.cpp
index ed28927..491b75d 100644
--- a/src/mathed/MathMacro.cpp
+++ b/src/mathed/MathMacro.cpp
@@ -22,6 +22,7 @@
 #include "MathSupport.h"
 
 #include "Buffer.h"
+#include "BufferList.h"
 #include "BufferView.h"
 #include "CoordCache.h"
 #include "Cursor.h"
@@ -180,7 +181,10 @@ void MathMacro::assign(MathMacro const & that)
                // We need to update macro_ by ourselves because in this case
                // MathData::metrics() is not called when selecting a math inset
                DocIterator const & pos = macroBackup_.pos();
-               macro_ = pos.buffer() ? pos.buffer()->getMacro(name(), pos) : 0;
+               Buffer const * buf = pos.buffer();
+               if (buf && !theBufferList().isLoaded(buf))
+                       buf = 0;
+               macro_ = buf ? buf->getMacro(name(), pos) : 0;
                if (!macro_)
                        macro_ = &macroBackup_;
        }

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