[Qt-creator] Qt Creator 2.7 onward does not work with some gdb on Windows

[André Pönitz]

On Sat, Jun 01, 2013 at 05:04:07PM +0530, Abir Basak wrote:
> I noticed that my MinGW w64 gdb stopped working when I updated from QtC
> 2.6.2 to QtC 2.7 . It no longer loads stack frame and locals and
> expressions automatically. The gdb is from MingW w64 project build by
> ruben vb , And it shows like GNU gdb (rubenvb-4.7.2-release)
> 7.5.50.20120920-cvs
> 
> I previously mailed about it, but there was no update after an initial
> reply. I looked at the source code of QtC to check if I can detect why it
> is not working (unfortunately I can not build & debug QtC, as I do not
> have a Qt distribution, I use it for my C++ library with make file based
> project).
> 
> It looks like extractGdbVersion does not handle the gdb version like the
> one shown above. From code it looks that it parses 4.7.2 as gdb version
> and makes it 407020, while it should go for the last part. I do not know
> standard gdb versioning strategy but it looks many use vendor specific
> information in brackets, so it should reject any number inside brackets.

If that's indeed the reason (and it sounds plausible) someone should
maybe ask the person providing that GDB build to not patch the version
string, or at least to not deviate too much from what other distributions do. 

A couple of version strings that are recognized are in the
"version" test in test/auto/debugger/tst_gdb.cpp.

> QtC 6.4.2 uses to load python based debuggers even when it failed with
> UNSUPPORTED GDB VERSION message due to wrong extractGdbVersion , but QtC 4.7
> onward handleHasPython was refactored to have a call handlePythonSetup ( I was
> unable to get which commit changed that) and it no longer calls the python
> specific loads.
> 
> I am looking for extractGdbVersion to fix for gdb version as shown above (Or
> even a user specific override option to inform the gdb has python support) so
> that I can work with newer QtC  versions (I have a lot of C++11 code like
> template alias which highlights only with newer QtC versions)

It's not just a question of Python or not Python. The version of GDB does
matter when it comes to decide what features to use, or whether certain
workarounds are needed. In some cases it's possible to check for features
at run time, so the exact version does not have to be known for that. But
there are also cases where just trying to enable some feature freezes or
crashes some GDB builds while it works fine on others.

Andre'