Update gn's depfile help text to include more guidance.

Update gn's depfile help text to include more guidance.

Committed: https://crrev.com/76097c7f435951726c7eaedc728271c084b5517d
Cr-Commit-Position: refs/heads/master@{#419555}

[agrieve, 2016-09-16 17:01:07]

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

[Dirk Pranke, 2016-09-16 17:08:06]

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

[Dirk Pranke, 2016-09-16 17:08:07]

+thakis for the ninja question/input ...

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc
File tools/gn/variables.cc (right):

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc#newco...
tools/gn/variables.cc:1044: "  an input.\n"
Does anything actually use depfiles as inputs? 

I wonder if listing depfiles as outputs actually works correctly at all; doesn't
ninja treat them as transient files and delete them once they've been parsed and
stored in .ninja_deps? Maybe it doesn't delete them if they are also outputs?

[brettw, 2016-09-16 17:20:37]

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc
File tools/gn/variables.cc (right):

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc#newco...
tools/gn/variables.cc:1044: "  an input.\n"
Can you check on the Ninja list to see if this is good guidance?

[agrieve, 2016-09-16 17:51:42]

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc
File tools/gn/variables.cc (right):

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc#newco...
tools/gn/variables.cc:1044: "  an input.\n"
On 2016/09/16 17:20:37, brettw (ping on IM after 24h) wrote:
> Can you check on the Ninja list to see if this is good guidance?

Good idea. Started thread:
https://groups.google.com/d/msg/ninja-build/buVgKjyVYU4/xFygHWaPBAAJ

[agrieve, 2016-09-19 18:14:18]

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc
File tools/gn/variables.cc (right):

https://codereview.chromium.org/2349743002/diff/1/tools/gn/variables.cc#newco...
tools/gn/variables.cc:1044: "  an input.\n"
On 2016/09/16 17:51:42, agrieve wrote:
> On 2016/09/16 17:20:37, brettw (ping on IM after 24h) wrote:
> > Can you check on the Ninja list to see if this is good guidance?
> 
> Good idea. Started thread:
> https://groups.google.com/d/msg/ninja-build/buVgKjyVYU4/xFygHWaPBAAJ

I've gotten no objections to the added advice.

[brettw, 2016-09-19 19:28:59]

lgtm

[Dirk Pranke, 2016-09-19 19:48:00]

I still kinda think that having the same file be used for both deps and as an
input is a bad idea, but if there's no bug I can live w/ this.

lgtm.

[agrieve, 2016-09-19 20:25:30]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2016-09-19 20:26:05]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-19 21:29:42]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-09-19 21:31:42]

Description was changed from

==========
Update gn's depfile help text to include more guidance.
==========

to

==========
Update gn's depfile help text to include more guidance.

Committed: https://crrev.com/76097c7f435951726c7eaedc728271c084b5517d
Cr-Commit-Position: refs/heads/master@{#419555}
==========

[commit-bot: I haz the power, 2016-09-19 21:31:43]

Patchset 2 (id:??) landed as
https://crrev.com/76097c7f435951726c7eaedc728271c084b5517d
Cr-Commit-Position: refs/heads/master@{#419555}