Option for noise-is-failure

[mdempsky]

It would be nice if Ninja had a command-line option to continue running if any commands produce output, but to treat the overall invocation as failure. Or even to treat all noisy targets as failed.

The motivation for this is crbug.com/376586.

[jhasse]

Why not use -Werror instead?

[mdempsky]

Not every noisy build is caused by gcc/clang output. For example, crbug.com/370981 (linked from crbug.com/376586, above) was due to a noisy Python script.

[jhasse]

Ah I see. So you want the whole build to be silent, otherwise it's a failure, correct? Couldn't you just check if there was any output in CI after ninja has completed?

[mdempsky]

In normal operation, ninja itself is quite noisy (e.g., printing build targets and progress). Is there an easy way to distinguish this noise from child process noise?

[jhasse]

You can change the build status with the env variable NINJA_STATUS. This will only print output not produced by ninja for example:

env NINJA_STATUS="ninja: " ninja 2>&1 | grep -v "^ninja: "

[jhasse]

Having a quiet option (#480) might also be useful.

[nico]

The motivation here is that we want the chrome build to be silent, but still have "normal" build output (the command description) on all the bots. Currently, we manually file bugs if any command produces output, but that becomes tricky as we build on more and more platforms.

[jhasse]

You can do that with:

env NINJA_STATUS="ninja: " ninja 2>&1 | ack --passthru --invert "^ninja: "

ack's exit code will be 0 if any command produced output.