Re: [PATCH v2] hook: allow hooks to disable stdout_to_stderr

> The last batch of hooks converted to the hook.[ch] API introduced
> a regression because pick_next_hook() always sets stdout_to_stderr
> for its child processes.
>
> Pre-push is the only hook API user which requires stdout_to_stderr
> to be 0, so it can be argued that pre-push needs fixing, however
> this will likely break many pre-push hooks, so it's better to allow
> it to be 0, i.e. to match the previous behavior.
>
> To prevent such regressions in the future, extend the hook tests to
> verify hooks write to the expected stdout vs stderr streams and
> maintain backward compatibility with the hooks output assumptions.
>
> The tests are independent of the actual hook implementations: I've
> tested they work the same before and after the hook.[ch] conversion
> and will continue to work after we eventually introduce parallel
> hook execution and config-based hooks.
>
> Reported-by: Chris Darroch <chrisd@apache.org>
> Suggested-by: brian m. carlson <sandals@crustytoothpaste.net>
> Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
> ---
> This is based on the latest master branch.
>
> Changes in v2:
> * Extended hook test coverage to detect future regressions (Junio, Patrick)
> * Reworded commit message and added explanatory comment (Junio, Patrick)
> * Set ungroup = 1 because grouping overrides stdout_to_stderr (Adrian)
>[snip]