Re: fatal output from git-show really wants a terminal

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> "Boyd Stephen Smith Jr." <bss03@volumehost.net> writes:
>
>>>  $ git log >foo.out
>>>
>>>and start a pager, which makes no sense.
>>
>> Good point, I'll try and consider that while I investgate the history of the 
>> issue.
>
> Isn't the issue about 61b8050 (sending errors to stdout under $PAGER,
> 2008-02-16)?  With that commit, we changed things so that when we send the
> standard output to the $PAGER, we dup stderr to the $PAGER as well,
> because otherwise any output to stderr will be wiped out by whatever the
> pager does and the user will not notice the breakage.  E.g.
>
> 	$ git log
>
> will just show reams of output, and you won't see any errors and warnings
> even if there were any encountered during the process.
>
> Unfortunately we did it unconditionally.  There is no reason to dup stderr
> to the $PAGER if the command line was:
>
> 	$ git log 2>error.log
>
> in which case you would want to view the normal output in your $PAGER and
> you are keeping the log of the error output in a separate file.

I haven't heard anything more about this, but if you were indeed
discussing the change made by 61b8050, I think the fix should just be like
this.

 pager.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git c/pager.c w/pager.c
index aa0966c..f19ddbc 100644
--- c/pager.c
+++ w/pager.c
@@ -70,7 +70,8 @@ void setup_pager(void)
 
 	/* original process continues, but writes to the pipe */
 	dup2(pager_process.in, 1);
-	dup2(pager_process.in, 2);
+	if (isatty(2))
+		dup2(pager_process.in, 2);
 	close(pager_process.in);
 
 	/* this makes sure that the parent terminates after the pager */