Forward flags to sub processes. #1079
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When ninja invokes ninja (for instance when building a sub-project) it is useful to have a way to control the flags used by the sub-ninja process. If I pass '-d explain' or '-v' when starting ninja from the command line on the top project, I expect these flags to be forwarded to the sub-ninja process. Note that this patch has limited parsing capabilities of the NINJA_FLAGS environment variables but that should be enough for our use case. Fixes ninja-build#797, ninja-build#922 and ninja-build#816.
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As mentioned on the mailing list, I don't think we should make recursive ninja a thing. I don't think this is a good change. |
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@nico, Could you link to the mailing list discussion you're referring to? |
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https://groups.google.com/forum/#!searchin/ninja-build/%22recursive$20ninja%22 finds a few threads, and I think there are several threads on a jobserver where it's also been discussed. |
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Okay, I'd found some of those. In particular these two (for anyone else stumbling across this PR): https://groups.google.com/forum/#!searchin/ninja-build/"recursive$20ninja"/ninja-build/niYOkWjkPW8/LSgArOH_ZZoJ But I guess I was expecting to find a thread that ended in some kind of definitive solution or consensus. For the parallel jobs problem it seems like the current stance from the Ninja team can be summed up as: ALL the world should migrate to Ninja together and start using subninja. Changes like making Ninja jobserver-aware to ease the transition from a Makefile-dominated world are unacceptable because it wouldn't showcase all of Ninjas awesome performance optimizations. In the case where both parent and child project are CMake-based the proposed solution to teach CMake to use the subninja command definitely makes sense and that work has begun here: http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/15364 |
When ninja invokes ninja (for instance when building a sub-project) it
is useful to have a way to control the flags used by the sub-ninja
process. If I pass '-d explain' or '-v' when starting
ninja from the command line on the top project, I expect these flags
to be forwarded to the sub-ninja process.
Note that this patch has limited parsing capabilities of the
NINJA_FLAGS environment variables but that should be enough for our
use case.
Fixes #797, #922 and #816.