Re: [PATCH/RFC] alias: use run_command api to execute aliases

[Jonathan Nieder <jrnieder@gmail.com>]

Erik Faye-Lund wrote:

> --- a/git.c
> +++ b/git.c
> @@ -177,19 +177,20 @@ static int handle_alias(int *argcp, const char ***argv)
[...]
> -			trace_printf("trace: alias to shell cmd: %s => %s\n",
> -				     alias_command, alias_string + 1);

Replaced by

	trace: run_command: ...

(followed by "trace: exec: ..." on non-Windows (execv_shell_cmd)).
Ok.

> -			ret = system(alias_string + 1);
> +
> +			/* build alias_argv */
> +			alias_argv = malloc(sizeof(char *) * *argcp + 1);

This seems to be missing parentheses, so valgrind will complain
except on 8-bit systems. ;-)

What if malloc fails?

> +			alias_argv[0] = alias_string + 1;
> +			for (i = 1; i < *argcp; ++i)
> +				alias_argv[i] = (*argv)[i];
> +			alias_argv[*argcp] = NULL;

Nit: all these *argcp are noisy.

> +
> +			ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
> +
>  			if (ret >= 0 && WIFEXITED(ret) &&

The return value from run_command and from system do not mean
the same thing.

>  			die("Failed to run '%s' when expanding alias '%s'",
>  			    alias_string + 1, alias_command);

run_command already prints an error message, but this one still
seems useful since it mentions the alias.

Except as noted above,
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks.

diff --git a/git.c b/git.c
index 5b0b9d8..dbf061d 100644
--- a/git.c
+++ b/git.c
@@ -178,22 +178,20 @@ static int handle_alias(int *argcp, const char ***argv)
 	if (alias_string) {
 		if (alias_string[0] == '!') {
 			const char **alias_argv;
-			int i;
+			int argc = *argcp, i;
 
 			commit_pager_choice();
 
-			/* build alias_argv */
-			alias_argv = malloc(sizeof(char *) * *argcp + 1);
+			alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
 			alias_argv[0] = alias_string + 1;
-			for (i = 1; i < *argcp; ++i)
+			for (i = 1; i < argc; ++i)
 				alias_argv[i] = (*argv)[i];
-			alias_argv[*argcp] = NULL;
+			alias_argv[argc] = NULL;
 
 			ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
+			if (ret >= 0)	/* normal exit */
+				exit(ret);
 
-			if (ret >= 0 && WIFEXITED(ret) &&
-			    WEXITSTATUS(ret) != 127)
-				exit(WEXITSTATUS(ret));
 			die("Failed to run '%s' when expanding alias '%s'",
 			    alias_string + 1, alias_command);
 		}