The user-supplied command spawned by 'submodule foreach' loses its
connection to the original standard input. Instead, it is connected to the
output of a pipe within the git-submodule script. The user-supplied
command supplied to 'submodule foreach' is spawned within a while loop
which is being piped into. Due to the way shells implement piping output
to a while loop, a subshell is created with its standard input attached to
the output of the pipe. This results in all of the commands executed
within the while loop to have their stdins modified in the same way,
including the user-supplied command.
This can cause a problem if the command requires reading from stdin or if
it changes its behavior based on whether stdin is a tty or not. For
example, this problem was noticed when trying to execute the following:
git submodule foreach git shortlog --since=two.weeks.ago
which printed a message about entering the first submodule and produced no
further output and exited with a status of zero. In this case, shortlog
detected that it was not connected to a tty, and since no revision was
supplied as an argument, it attempted to read the list of revisions from
standard input. Instead, it slurped up the list of submodules that was
being piped to the enclosing while loop and caused that loop to end early
without processing the remaining submodules.
Work around this behavior by saving the original standard input file
descriptor before the while loop, and restoring it when spawning the
user-supplied command.
This fixes the tests in t7407.
Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
////////////////////////////////////////////////////////////////
GIT - the stupid content tracker
////////////////////////////////////////////////////////////////
"git" can mean anything, depending on your mood.
- random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
- "global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public License.
It was originally written by Linus Torvalds with help of a group of
hackers around the net. It is currently maintained by Junio C Hamano.
Please read the file INSTALL for installation instructions.
See Documentation/gittutorial.txt to get started, then see
Documentation/everyday.txt for a useful minimum set of commands, and
Documentation/git-commandname.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with "man gittutorial" or "git help tutorial", and the
documentation of each command with "man git-commandname" or "git help
commandname".
CVS users may also want to read Documentation/gitcvs-migration.txt
("man gitcvs-migration" or "git help cvs-migration" if git is
installed).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
The user discussion and development of Git take place on the Git
mailing list -- everyone is welcome to post bug reports, feature
requests, comments and patches to git@vger.kernel.org. To subscribe
to the list, send an email with just "subscribe git" in the body to
majordomo@vger.kernel.org. The mailing list archives are available at
http://marc.theaimsgroup.com/?l=git and other archival sites.
The messages titled "A note from the maintainer", "What's in
git.git (stable)" and "What's cooking in git.git (topics)" and
the discussion following them on the mailing list give a good
reference for project status, development direction and
remaining tasks.
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