Switch gyp_chromium from third_party/python_26, which is gone, to

Switch gyp_chromium from third_party/python_26, which is gone, to
depot_tools/python276_bin.

BUG=335180
TEST=gclient runhooks works again on Cygwin
R=maruel@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=245705

[M-A Ruel, 2014-01-18 00:10:57]

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium
File build/gyp_chromium (right):

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium#newcode308
build/gyp_chromium:308: python_dir = os.path.join(depot_tools_path,
'python276_bin')
The main issue is that it is not forward compatible. I'd prefer it to search
imediate subdirectories for a python.exe.

[Peter Kasting, 2014-01-18 00:13:23]

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium
File build/gyp_chromium (right):

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium#newcode308
build/gyp_chromium:308: python_dir = os.path.join(depot_tools_path,
'python276_bin')
On 2014/01/18 00:10:58, M-A Ruel wrote:
> The main issue is that it is not forward compatible. I'd prefer it to search
> imediate subdirectories for a python.exe.

The problem here is that there's also a "python_bin" dir which contains a
python.exe that is python 2.6.

I would love to see that directory die, so that "python_bin" was the one and
only python, but I don't know the history of this directory or why that hasn't
been done already.  Until then, I don't know how one would write the
aforementioned search.

[M-A Ruel, 2014-01-18 00:16:39]

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium
File build/gyp_chromium (right):

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium#newcode308
build/gyp_chromium:308: python_dir = os.path.join(depot_tools_path,
'python276_bin')
On 2014/01/18 00:13:23, Peter Kasting wrote:
> On 2014/01/18 00:10:58, M-A Ruel wrote:
> > The main issue is that it is not forward compatible. I'd prefer it to search
> > imediate subdirectories for a python.exe.
> 
> The problem here is that there's also a "python_bin" dir which contains a
> python.exe that is python 2.6.
> 
> I would love to see that directory die, so that "python_bin" was the one and
> only python, but I don't know the history of this directory or why that hasn't
> been done already.  Until then, I don't know how one would write the
> aforementioned search.

python_exe = sorted(glob.glob(os.path.join(depot_tools_path,
'python2*_bin/python.exe')))[-1]

[Peter Kasting, 2014-01-18 00:20:27]

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium
File build/gyp_chromium (right):

https://codereview.chromium.org/141563007/diff/1/build/gyp_chromium#newcode308
build/gyp_chromium:308: python_dir = os.path.join(depot_tools_path,
'python276_bin')
On 2014/01/18 00:16:40, M-A Ruel wrote:
> On 2014/01/18 00:13:23, Peter Kasting wrote:
> > On 2014/01/18 00:10:58, M-A Ruel wrote:
> > > The main issue is that it is not forward compatible. I'd prefer it to
search
> > > imediate subdirectories for a python.exe.
> > 
> > The problem here is that there's also a "python_bin" dir which contains a
> > python.exe that is python 2.6.
> > 
> > I would love to see that directory die, so that "python_bin" was the one and
> > only python, but I don't know the history of this directory or why that
hasn't
> > been done already.  Until then, I don't know how one would write the
> > aforementioned search.
> 
> python_exe = sorted(glob.glob(os.path.join(depot_tools_path,
> 'python2*_bin/python.exe')))[-1]

That's certainly a little better, but it still assumes python is in a "python2*"
directory.  Why can't we just kill python_bin and move python276_bin to that?

[M-A Ruel, 2014-01-18 00:27:55]

On 2014/01/18 00:20:27, Peter Kasting wrote:
> > python_exe = sorted(glob.glob(os.path.join(depot_tools_path,
> > 'python2*_bin/python.exe')))[-1]
> 
> That's certainly a little better, but it still assumes python is in a
"python2*"
> directory.  Why can't we just kill python_bin and move python276_bin to that?

python_bin is only present in old installation. You can safely delete it after
the upgrade. The auto-upgrade code cannot delete it because when the upgrade
occurs, it doesn't know if a python process exists, so there's no way to know if
the python_bin can be deleted. This is particularly true on the buildbot slaves.

As long as the code is python 2.x, it's guaranteed to have the format
python2xxx_bin. As long as the numbers are monotonically incrementing, it's
fine.

[M-A Ruel, 2014-01-18 00:29:40]

On 2014/01/18 00:27:55, M-A Ruel wrote:
> On 2014/01/18 00:20:27, Peter Kasting wrote:
> > > python_exe = sorted(glob.glob(os.path.join(depot_tools_path,
> > > 'python2*_bin/python.exe')))[-1]
> > 
> > That's certainly a little better, but it still assumes python is in a
> "python2*"
> > directory.  Why can't we just kill python_bin and move python276_bin to
that?
> 
> python_bin is only present in old installation. You can safely delete it after
> the upgrade. The auto-upgrade code cannot delete it because when the upgrade
> occurs, it doesn't know if a python process exists, so there's no way to know
if
> the python_bin can be deleted. This is particularly true on the buildbot
slaves.
> 
> As long as the code is python 2.x, it's guaranteed to have the format
> python2xxx_bin. As long as the numbers are monotonically incrementing, it's
> fine.

This was documented in the faq in the announcement at
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/YhMhXaS0gHo/pdGqV...

[Peter Kasting, 2014-01-18 00:56:22]

Updated.  I also uploaded https://codereview.chromium.org/141523009/ separately
to ensure that Cygwin users actually have a relevant python directory in
depot_tools/ to make use of.

[M-A Ruel, 2014-01-18 00:58:50]

lgtm

[Peter Kasting, 2014-01-18 01:29:58]

Committed patchset #2 manually as r245705 (presubmit successful).