906403 - Some subconfigures fail in incremental builds when some flags like CFLAGS change

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Mike Hommey [:glandium]]

When we change the value of e.g CFLAGS, subconfigure may fail with a message saying the value changed, and to either run make distclean or remove config.cache. This is annoying, especially on buildbots, where to unblock the slave, it needs a clobber, which can create more work than is probably necessary (adding, for example, a warning flag is not really a good reason to force a clobber).

With the wrapping from bug 903369, it's now possible to remove config.cache when we detect configure would fail, avoiding the failure.

Comment 1

[Mike Hommey [:glandium]]

Attachment: Avoid subconfigure fail in incremental builds when some variable like CFLAGS change

Comment 2

[Gregory Szorc [:gps]]

Comment on attachment 791789 [details] [diff] [review]
Avoid subconfigure fail in incremental builds when some variable like CFLAGS change

Review of attachment 791789 [details] [diff] [review]:
-----------------------------------------------------------------

::: build/subconfigure.py
@@ +48,5 @@
> +# straighten things is to either run make distclean or config.cache. There's
> +# no reason not to do it automatically instead of failing, doing the cleanup
> +# (which, on buildbots means a full clobber), and restarting from scratch.
> +def maybe_clear_cache():
> +    import re

Nit: Import at file scope.

Comment 3

[Mike Hommey [:glandium]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e616268dba3c

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/e616268dba3c