Re: [PATCH v6 3/3] run-command: show prepared command

Junio C Hamano
2024-05-26T16:20:56Z

Ian Wienand <iwienand@redhat.com> writes:

> This adds a trace point in start_command so we can see the full
> command invocation without having to resort to strace/code inspection.
> For example:
>
> $ GIT_TRACE=1 git test foo
> git.c:755 trace: exec: git-test foo
> run-command.c:657 trace: run_command: git-test foo
> run-command.c:657 trace: run_command: 'echo $*' foo
> run-command.c:749 trace: start_command: /bin/sh -c 'echo $* "$@"' 'echo $*' foo
>
> Prior changes have made the documentation around the internals of the
> alias command execution clearer, but I have still found this detailed
> view of the aliased command being run helpful for debugging purposes.
>
> A test case is added. This simply looks for the trace point output;
> the details change depending on platform -- the important thing is
> that we have a verbose log point, not so much the details of what
> happens on each platform.
>
> Signed-off-by: Ian Wienand <iwienand@redhat.com>
> ---
> run-command.c | 3 +++
> t/t0014-alias.sh | 12 ++++++++++++
> 2 files changed, 15 insertions(+)
>
> diff --git a/run-command.c b/run-command.c
> index 1b821042b4..31b20123d8 100644
> --- a/run-command.c
> +++ b/run-command.c
> @@ -746,6 +746,8 @@ int start_command(struct child_process *cmd)
> goto end_of_spawn;
> }
>
> + trace_argv_printf(&argv.v[1], "trace: start_command:");
> +
> if (pipe(notify_pipe))
> notify_pipe[0] = notify_pipe[1] = -1;
>
> @@ -913,6 +915,7 @@ int start_command(struct child_process *cmd)
> else if (cmd->use_shell)
> cmd->args.v = prepare_shell_cmd(&nargv, sargv);
>
> + trace_argv_printf(cmd->args.v, "trace: start_command:");
> cmd->pid = mingw_spawnvpe(cmd->args.v[0], cmd->args.v,
> (char**) cmd->env.v,
> cmd->dir, fhin, fhout, fherr);
> diff --git a/t/t0014-alias.sh b/t/t0014-alias.sh
> index 95568342be..634f6d78ef 100755
> --- a/t/t0014-alias.sh
> +++ b/t/t0014-alias.sh
> @@ -44,4 +44,16 @@ test_expect_success 'run-command formats empty args properly' '
> test_cmp expect actual
> '
>
> +test_expect_success 'tracing a shell alias with arguments shows trace of prepared command' '
> + cat >expect <<-EOF &&
> + trace: start_command: SHELL -c ${SQ}echo \$* "\$@"${SQ} ${SQ}echo \$*${SQ} arg
> + EOF
> + git config alias.echo "!echo \$*" &&
> + env GIT_TRACE=1 git echo arg 2>output &&
> + # redact platform differences
> + cat output &&

That "cat" is not about "redact"ing platform differences. Leftover
debugging? I'll remove it while queuing.

> + sed -n -e "s/^\(trace: start_command:\) .* -c /\1 SHELL -c /p" output >actual &&
> + test_cmp expect actual
> +'

Other than that, this step looks good to me.

Thanks.