bzr 1.14: Installing from source broken by default on Windows when compiling extensions

[John Arbash Meinel]

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Gary van der Merwe wrote:
> On Fri, May 1, 2009 at 4:30 PM, John Arbash Meinel
> <john at arbash-meinel.com> wrote:
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>>
>> It is a problem when using the pure python executable to build the
>> pure-win32 extensions. It knows how to find 'gcc.exe' but not when that
>> object is a symlink.
>>
>> If you set 'compiler = mingw' (or python setup.py -c mingw) it will
>> search for C:\cygwin\bin\gcc.exe
>> And it knows to pass '-mno-cygwin' so that you don't end up with a
>> binary that is built against cygwin?.dll.
>>
>> I do this intentionally because I *don't* want to accidentally use the
>> cygwin python and build cygwin extensions. (IIRC, cygwin python will
>> actually build .dll files instead of .pyd, for a bit of special
>> craziness, which means you can actually build *both* cygwin dlls and
>> win32 dlls in the same place, as long as you build the win32 ones
>> *first* so win32 python doesn't try to load the cygwin version.)
>>
>> John
>> =:->
>>
> 
> I just checked - I don't have cygwin's python installed, and it must
> be using "pure-python" cause it's creating .pyd files.
> 
> Just to confirm - If I run
> python setup.py build -c mingw32
> 
> in command prompt  - I get :
> 
> building 'bzrlib._btree_serializer_c' extension
> gcc -mno-cygwin -mdll -O -Wall -DWIN32 -IC:\Python25\include
> -IC:\Python25\PC -c bzrlib/_btree_serializer_c.c -o
> build\temp.win32-2.5\Release\bzrlib\_btree_serializer_c.o
> 
>   Cannot build extension "bzrlib._btree_serializer_c".
>   Use "build_ext --allow-python-fallback" to use slower python
> implementations instead.
> 
> error: command 'gcc' failed: No such file or directory
> 
> and from cygwin bash shell it works.
> 

Which 'python' are you running in both situations? I'm guessing the
latter is using cygwin's python, and the former is using win32 python.

Mostly stated, because I do, indeed, run under bash *all the time*, I
just call out to the native python interpreter to run things. (I alias
it to 'py' but that is just an implementation detail.)

I would double check the extensions that are getting built. We may be
fine, if they are, indeed, using -mno-cygwin.

But win32 python's 'subprocess' module has no way of following cygwin
symlinks in order to invoke 'gcc' directly.

John
=:->
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