deps2git: Add support for overriding DEPS vars

deps2git: Add support for overriding DEPS vars

This makes it possible to override variables used
in DEPS files, similar to how the custom_vars dict
in gclient solutions behaves.

BUG=419516

[kjellander_chromium, 2014-10-01 17:13:14]

kjellander@chromium.org changed reviewers:
+ hinoka@chromium.org

[kjellander_chromium, 2014-10-01 17:14:43]

I don't have the deep knowledge to predict if this is entirely safe. Can you run
some tests for me?

This would make it possible for WebRTC to use bot_update without having to
change how our DEPS file and everyone's checkouts are setup.

[hinoka, 2014-10-02 21:05:50]

hinoka@chromium.org changed reviewers:
+ szager@google.com

[hinoka, 2014-10-02 21:05:51]

+szager for review

It looks okay to me, but I also don't have a deep knowledge of this.  I'd
usually test this by running a full bot_update cycle.  I'm a bit confused why
you have to add it to the local scope "vars" also (actually i'm also confused
why the local scoping exists..)

https://codereview.chromium.org/619133002/diff/1/deps2git.py
File deps2git.py (right):

https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
deps2git.py:309: type='string', nargs=1, default={},
nargs is redundant.

[szager1, 2014-10-02 21:16:22]

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

[szager1, 2014-10-02 21:16:23]

https://codereview.chromium.org/619133002/diff/1/deps2git.py
File deps2git.py (right):

https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
deps2git.py:309: type='string', nargs=1, default={},
Prefer default=None

https://codereview.chromium.org/619133002/diff/1/deps_utils.py
File deps_utils.py (right):

https://codereview.chromium.org/619133002/diff/1/deps_utils.py#newcode19
deps_utils.py:19: def __init__(self, local_scope, custom_vars=None):
Can you use a different name than custom_vars, here and elsewhere?  That's an
overloaded term, since gclient supports a 'custom_vars' item inside a solution. 
Maybe 'var_overrides'.

[kjellander_chromium, 2014-10-03 07:13:31]

Updated according to comments.

https://codereview.chromium.org/619133002/diff/1/deps2git.py
File deps2git.py (right):

https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
deps2git.py:309: type='string', nargs=1, default={},
On 2014/10/02 21:05:51, hinoka wrote:
> nargs is redundant.

Done.

https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
deps2git.py:309: type='string', nargs=1, default={},
On 2014/10/02 21:16:22, szager1 wrote:
> Prefer default=None

Done.

https://codereview.chromium.org/619133002/diff/1/deps_utils.py
File deps_utils.py (right):

https://codereview.chromium.org/619133002/diff/1/deps_utils.py#newcode19
deps_utils.py:19: def __init__(self, local_scope, custom_vars=None):
On 2014/10/02 21:16:22, szager1 wrote:
> Can you use a different name than custom_vars, here and elsewhere?  That's an
> overloaded term, since gclient supports a 'custom_vars' item inside a
solution. 
> Maybe 'var_overrides'.

You're absolutely right. I forgot that custom_vars in .gclient is on a solution
level, while what I'm implementing here is a global override for variables in
the DEPS file to be processed.

I changed it to var_overrides and made the help text a bit more descriptive.

[kjellander_chromium, 2014-10-03 07:26:39]

On 2014/10/03 07:13:31, kjellander wrote:
> Updated according to comments.
> 
> https://codereview.chromium.org/619133002/diff/1/deps2git.py
> File deps2git.py (right):
> 
> https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
> deps2git.py:309: type='string', nargs=1, default={},
> On 2014/10/02 21:05:51, hinoka wrote:
> > nargs is redundant.
> 
> Done.
> 
> https://codereview.chromium.org/619133002/diff/1/deps2git.py#newcode309
> deps2git.py:309: type='string', nargs=1, default={},
> On 2014/10/02 21:16:22, szager1 wrote:
> > Prefer default=None
> 
> Done.
> 
> https://codereview.chromium.org/619133002/diff/1/deps_utils.py
> File deps_utils.py (right):
> 
> https://codereview.chromium.org/619133002/diff/1/deps_utils.py#newcode19
> deps_utils.py:19: def __init__(self, local_scope, custom_vars=None):
> On 2014/10/02 21:16:22, szager1 wrote:
> > Can you use a different name than custom_vars, here and elsewhere?  That's
an
> > overloaded term, since gclient supports a 'custom_vars' item inside a
> solution. 
> > Maybe 'var_overrides'.
> 
> You're absolutely right. I forgot that custom_vars in .gclient is on a
solution
> level, while what I'm implementing here is a global override for variables in
> the DEPS file to be processed.
> 
> I changed it to var_overrides and made the help text a bit more descriptive.

FYI, I changed the title of this CL to "deps2git: Add support for overriding
DEPS vars"

[szager1, 2014-10-03 16:21:54]

lgtm

[kjellander_chromium, 2014-10-09 09:27:21]

I'm abandoning this CL since I removed the use of the custom_vars "root_dir"
variable that WebRTC had on the bots until now.