GN: Allow setting the path to Python

GN: Allow setting the path to Python

This allows setting the path to Python executable used by GN through
a command line argument so that it can be overriden by the user.

Committed: https://crrev.com/325472663a3576438dd275b2981d59764ea362fb
Cr-Commit-Position: refs/heads/master@{#393683}

[Petr Hosek, 2016-05-13 00:39:19]

phosek@chromium.org changed reviewers:
+ brettw@chromium.org

[Petr Hosek, 2016-05-13 00:42:41]

I wasn't sure whether to name the flag as "--python" or "--python-path" so I
went for the former, but I'd be happy to change this to the latter if you
prefer.

[Dirk Pranke, 2016-05-13 00:58:16]

dpranke@chromium.org changed reviewers:
+ dpranke@chromium.org

[Dirk Pranke, 2016-05-13 00:58:18]

I think we were talking about this not actually being python-specific, so maybe
--script-executable instead (though the docs and help string should say that we
default to looking for Python in your path)?

[Petr Hosek, 2016-05-13 01:03:37]

That'd be better as we plan to use that argument to change the interpreter to
something other than Python. Shall I also rename the python_path in
build_settings to script_executable (possibly in a separate change) or do you
want to keep it as it is?

[Dirk Pranke, 2016-05-13 01:08:18]

On 2016/05/13 01:03:37, Petr Hosek wrote:
> That'd be better as we plan to use that argument to change the interpreter to
> something other than Python. Shall I also rename the python_path in
> build_settings to script_executable (possibly in a separate change) or do you
> want to keep it as it is?

I defer these calls to brettw@ :). I think there was some talk of also being
able to pull a default value from the dotfile, though it's not clear how that
would work in a cross-platform way.

[Petr Hosek, 2016-05-13 01:12:30]

I've renamed the switch to script-executable.

[brettw, 2016-05-13 17:03:44]

lgtm

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc
File tools/gn/switches.cc (right):

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc#ne...
tools/gn/switches.cc:112: "  By default GN uses Python to execute scripts in
action targets and\n"
Can you change this to:

By default GN searches the PATH for Python to execute scripts in action targets
and exec_script calls. This flag allows the specification of a specific Python
executable or potentially a different language interpreter.

[brettw, 2016-05-13 17:04:15]

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc
File tools/gn/switches.cc (right):

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc#ne...
tools/gn/switches.cc:265: INSERT_VARIABLE(Threads)
Oh, also add here:
  INSERT_VARIABLE(ScriptExecutable)
so it appears in the overview help.

[Petr Hosek, 2016-05-13 18:13:47]

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc
File tools/gn/switches.cc (right):

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc#ne...
tools/gn/switches.cc:112: "  By default GN uses Python to execute scripts in
action targets and\n"
On 2016/05/13 17:03:44, brettw wrote:
> Can you change this to:
> 
> By default GN searches the PATH for Python to execute scripts in action
targets
> and exec_script calls. This flag allows the specification of a specific Python
> executable or potentially a different language interpreter.

Done.

https://codereview.chromium.org/1978693002/diff/20001/tools/gn/switches.cc#ne...
tools/gn/switches.cc:265: INSERT_VARIABLE(Threads)
On 2016/05/13 17:04:15, brettw wrote:
> Oh, also add here:
>   INSERT_VARIABLE(ScriptExecutable)
> so it appears in the overview help.

Done.

[Petr Hosek, 2016-05-13 21:32:06]

The CQ bit was checked by phosek@chromium.org

[Petr Hosek, 2016-05-13 21:32:07]

The patchset sent to the CQ was uploaded after l-g-t-m from brettw@chromium.org
Link to the patchset: https://codereview.chromium.org/1978693002/#ps40001
(title: "Update the switch help message")

[commit-bot: I haz the power, 2016-05-13 21:32:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1978693002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1978693002/40001

[Dirk Pranke, 2016-05-13 21:35:30]

The CQ bit was unchecked by dpranke@chromium.org

[Dirk Pranke, 2016-05-13 21:36:55]

On 2016/05/13 21:32:28, commit-bot: I haz the power wrote:
> CQ is trying da patch. Follow status at
>  https://chromium-cq-status.appspot.com/patch-status/1978693002/40001
> View timeline at
>  https://chromium-cq-status.appspot.com/patch-timeline/1978693002/40001

Whoops, unchecking ... can you update tools/gn/docs/reference.md with the new
help text (build a GN binary w/ these changes and run gn help --markdown all >
reference.md)?.

[Petr Hosek, 2016-05-13 21:40:46]

Done.

[Dirk Pranke, 2016-05-13 22:02:26]

lgtm

[Dirk Pranke, 2016-05-13 22:03:53]

On 2016/05/13 22:02:26, Dirk Pranke wrote:
> lgtm

looks like you need to rebase, though :(.

[Petr Hosek, 2016-05-13 22:42:09]

Done, looks good now.

[Dirk Pranke, 2016-05-13 23:09:20]

On 2016/05/13 22:42:09, Petr Hosek wrote:
> Done, looks good now.

Very good. CQ away :).

[Petr Hosek, 2016-05-13 23:14:50]

The CQ bit was checked by phosek@chromium.org

[Petr Hosek, 2016-05-13 23:14:50]

The patchset sent to the CQ was uploaded after l-g-t-m from brettw@chromium.org,
dpranke@chromium.org
Link to the patchset: https://codereview.chromium.org/1978693002/#ps80001
(title: "Rebase")

[commit-bot: I haz the power, 2016-05-13 23:15:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1978693002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1978693002/80001

[commit-bot: I haz the power, 2016-05-13 23:26:18]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-05-13 23:28:47]

Description was changed from

==========
GN: Allow setting the path to Python

This allows setting the path to Python executable used by GN through
a command line argument so that it can be overriden by the user.
==========

to

==========
GN: Allow setting the path to Python

This allows setting the path to Python executable used by GN through
a command line argument so that it can be overriden by the user.

Committed: https://crrev.com/325472663a3576438dd275b2981d59764ea362fb
Cr-Commit-Position: refs/heads/master@{#393683}
==========

[commit-bot: I haz the power, 2016-05-13 23:28:49]

Patchset 5 (id:??) landed as
https://crrev.com/325472663a3576438dd275b2981d59764ea362fb
Cr-Commit-Position: refs/heads/master@{#393683}