Re: Bugreport: Git responds with stderr instead of stdout

[Jeff King <peff@peff.net>]

On Sun, Apr 25, 2010 at 06:24:43PM +0000, Ævar Arnfjörð Bjarmason wrote:

> On Sun, Apr 25, 2010 at 18:10, Jacob Helwig <jacob.helwig@gmail.com> wrote:
> > I can't really say if it's actually a bug, or not, but as to your
> > question about where to file a bug report: You just did.  This mailing
> > list is the correct place.
> 
> I've had some issues scripting `git fetch` because on error it'll
> print to stdout and not stderr.

Errors should go to stderr, so I imagine patches would be welcome. Which
messages went to stdout?

> Are there some general guidelines for git's utilities that they follow
> in this regard or does each tool just do its own thing?

In practice, each tool does its own thing because they evolved
differently and from different authors. I think we are slowly converging
on similar behavior, though, as people fix warts.  As to exactly what
that behavior is, I don't know that anybody has ever enumerated it
exactly. Verbose status and progress reports, especially human readable
ones, should probably always go to stderr.

The "Switched to a new branch" message that started this thread is
correct to go to stderr.  If you want to silence the message but keep
stderr open for actual errors, the right way is to use "-q".

I tend to think the only thing that should go to stdout is the "main"
output of a command. For something like "ls-files", that is obviously
the list of files. For something like "checkout", which is about
changing the repository and not about querying it, I think there is
probably nothing that makes sense on stdout.

-Peff