When run_command() was asked to run a non-existant command, its behavior
varied depending on the platform:
- on POSIX systems, we would fork, and then after the execvp call
failed, we could call die(), which prints a message to stderr and
exits with code 128.
- on Windows, we do a PATH lookup, realize the program isn't there, and
then return ERR_RUN_COMMAND_FORK
The goal of this patch is to make it clear to callers that the specific
error was a missing command. To do this, we will return the error code
ERR_RUN_COMMAND_EXEC, which is already defined in run-command.h, checked
for in several places, but never actually gets set.
The new behavior is:
- on POSIX systems, we exit the forked process with code 127 (the same
as the shell uses to report missing commands). The parent process
recognizes this code and returns an EXEC error. The stderr message is
silenced, since the caller may be speculatively trying to run a
command. Instead, we use trace_printf so that somebody interested in
debugging can see the error that occured.
- on Windows, we check errno, which is already set correctly by
mingw_spawnvpe, and report an EXEC error instead of a FORK error
Thus it is safe to speculatively run a command:
int r = run_command_v_opt(argv, 0);
if (r == -ERR_RUN_COMMAND_EXEC)
/* oops, it wasn't found; try something else */
else
/* we failed for some other reason, error is in r */
Signed-off-by: Jeff King <peff@peff.net>
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 "man git-commandname" for documentation of each command.
CVS users may also want to read Documentation/cvs-migration.txt.
Many Git online resources are accessible from http://git.or.cz/
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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