Remove include_test*.fbs from build files

Remove include_test*.fbs from build files

Remove include_test*.fbs from the build files. Otherwise, these would be
translated into C++ source code multiple times and confuse GN. The
include_test*.fbs are already built via monster_test.fbs.

BUG=539572
Committed: https://crrev.com/6d78d1147d665e41d6bffe602d6baa8ef84d9997
Cr-Commit-Position: refs/heads/master@{#393235}

[battre, 2016-05-09 07:17:45]

battre@chromium.org changed reviewers:
+ engedy@chromium.org

[battre, 2016-05-09 07:17:45]

Balazs, could you please review this? It should fix the problems of
https://codereview.chromium.org/1955993002/

Thanks,
Dominic

[engedy, 2016-05-09 07:34:00]

https://codereview.chromium.org/1958033002/diff/20001/third_party/flatbuffers...
File third_party/flatbuffers/BUILD.gn (left):

https://codereview.chromium.org/1958033002/diff/20001/third_party/flatbuffers...
third_party/flatbuffers/BUILD.gn:60: "src/tests/include_test1.fbs",
I'd rather move these into a separate target that this
"flatbuffers_samplebuffer" target would depend on. 

If we completely removed the files, then the build system would have no
visibility into the build depending on them at all.

[battre, 2016-05-09 09:12:25]

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

[battre, 2016-05-09 09:12:25]

Brett, could you help us with this one?

For reference, this is what I am talking about:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/flatbu...
- in particular BUILD.gn and flatbuffer.gni

The problem is that the current approach of using compiled_action_foreach to
compile the flatbuffers IDL code to C++ processes files multiple times if they
are included in another file:

src/tests/monster_test.fbs starts with
include "include_test1.fbs";

So currently, monster_test.fbs is compiled, generating a file
include_test1_generated.h, and then include_test1.fbs is compiled, generating a
file include_test1_generated.h again. This confuses ninja's dependency graph
(see the failed try jobs of https://codereview.chromium.org/1955993002/). 

Ideally, I would not call the flatc compiler once for each source file, but one
time for all source files together. If I call "flatc monster_test.fbs
include_test1.fbs", the compiler would figure out that that
include_test1_generated.h would only need to be generated once. I haven't
figured out how to get that while keeping correct outputs (in the sense of
outputs = [ "$out_dir/{{source_name_part}}_generated.h" ]).

I have explored these options:

1) As Balazs suggested: create a new build target that contains only the
include_test*.fbs. The include_test*.fbs files would still be compiled multiple
times.

2) Using inputs = []: I explored to use inputs = [] to create dependencies. I
think that works for creating the dependencies but it fails to provide proper
outputs = [] entries.

3) flatc would be happy to take multiple frame buffer input files in one call. I
could call flatc with parameters "monster_test.fbs include_test1.fbs
include_test2.fbs" and it would figure out itself that it needs to generate the
code for the include_test*.fbs only once. But this is incompatible with
compiled_action_foreach(). I checked whether I could use compiled_action() but
then I don't know how to build the outputs as I cannot use the
{{source_name_part}} variable substitution (as in
"$out_dir/{{source_name_part}}_generated.h") in compiled_action().

Do you have any ideas?

Thanks,
Dominic

[engedy, 2016-05-11 16:35:53]

LGTM as a short-term workaround to unblock dependent CLs, could you please file
a bug to track proper resolution of this?

[battre, 2016-05-12 11:32:57]

The CQ bit was checked by battre@chromium.org

[battre, 2016-05-12 11:32:58]

The patchset sent to the CQ was uploaded after l-g-t-m from engedy@chromium.org
Link to the patchset: https://codereview.chromium.org/1958033002/#ps40001
(title: "Addressed Balazs' comments")

[commit-bot: I haz the power, 2016-05-12 11:33:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1958033002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1958033002/40001

[commit-bot: I haz the power, 2016-05-12 13:05:06]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-12 13:06:51]

Description was changed from

==========
Remove include_test*.fbs from build files

Remove include_test*.fbs from the build files. Otherwise, these would be
translated into C++ source code multiple times and confuse GN. The
include_test*.fbs are already built via monster_test.fbs.

BUG=539572
==========

to

==========
Remove include_test*.fbs from build files

Remove include_test*.fbs from the build files. Otherwise, these would be
translated into C++ source code multiple times and confuse GN. The
include_test*.fbs are already built via monster_test.fbs.

BUG=539572

Committed: https://crrev.com/6d78d1147d665e41d6bffe602d6baa8ef84d9997
Cr-Commit-Position: refs/heads/master@{#393235}
==========

[commit-bot: I haz the power, 2016-05-12 13:06:52]

Patchset 3 (id:??) landed as
https://crrev.com/6d78d1147d665e41d6bffe602d6baa8ef84d9997
Cr-Commit-Position: refs/heads/master@{#393235}