Re: Weird behavior of shell variables in git aliases

From

Junio C Hamano <gitster@pobox.com>

Date

Mar 21, 2011, 22:33 UTC

Message-ID

<7v4o6wnlxm.fsf@alter.siamese.dyndns.org>

In-Reply-To

<7v8vw8nmh2.fsf@alter.siamese.dyndns.org>

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

> Jeff King <peff@peff.net> writes:
>
>> But interestingly, that's _not_ the behavior as of Erik's 7f51f8b
>> (alias: use run_command api to execute aliases, 2011-01-07), which is in
>> master but not yet released. With that, we end up executing:
>>
>>   sh -c 'echo $1 && echo $1 "$@"' 'echo $1 && echo $1' 'foo'
>>
>> which prints "foo foo". So it is technically a regression. I don't know
>> how much we care; using positional parameters like this was already
>> nonsensical, as shown above.
>>
>> For reference, what you actually want (in either system) is:
>>
>>   $ git config alias.test1
>>   !sh -c 'echo $1 && echo $1' -
>
> Oh, I should have been paying a bit more attention.  I've been assuming
> that we were turning "!anything" into { "sh", "-c", "anything", "-" }
> followed by the user supplied arguments.

The attached quick hack gives

  $ git config alias.silly
  !echo hello $1; echo $# args, bye!
  $ GIT_TRACE=1 ./git silly world funny
  trace: exec: 'git-silly' 'world' 'funny'
  trace: run_command: 'git-silly' 'world' 'funny'
  trace: run_command: 'sh' '-c' 'echo hello $1; echo $# args, bye'\!'' '-' 'world' 'funny'
  trace: exec: 'sh' '-c' 'echo hello $1; echo $# args, bye'\!''
  '-' 'world' 'funny'
  hello world
  2 args, bye!

 git.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/git.c b/git.c
index ef598c3..8d54466 100644
--- a/git.c
+++ b/git.c
@@ -183,11 +183,14 @@ static int handle_alias(int *argcp, const char ***argv)
 			commit_pager_choice();
 
 			/* build alias_argv */
-			alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
-			alias_argv[0] = alias_string + 1;
+			alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 4));
+			alias_argv[0] = "sh";
+			alias_argv[1] = "-c";
+			alias_argv[2] = alias_string + 1;
+			alias_argv[3] = "-";
 			for (i = 1; i < argc; ++i)
-				alias_argv[i] = (*argv)[i];
-			alias_argv[argc] = NULL;
+				alias_argv[i + 3] = (*argv)[i];
+			alias_argv[argc + 3] = NULL;
 
 			ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
 			if (ret >= 0)   /* normal exit */