git.c: fix, stop passing options after --help

Commit Message

Daniel Sonbolian Oct. 10, 2022, 4:17 p.m. UTC

From: Daniel Sonbolian <[e-mail]>

Since commit c6b6d9f7d8a when passing --help option
to a Git command, we try to open that command man page, we
do it for both commands and concepts, it is done by
converting the entered command to a help command
for the given Git command, for example:

	"git commit --help -i" into "git help --exclude-guides commit -i"

But the options after --help option are also
passed to the new command (-i option from the example)
which can lead to unexpected output, because the
help command will try to execute those extra options.

This fixed by building the argv statically, meaning
instead of switching places between argv arguments and then
passing all the arguments to a new memory vector that will
later be used as the new argv, we directly passing that
memory vector only the required arguments and in the
correct order, after that we also updating the
argc to a static number:

	strvec_push(&args, "help");  // argv[0]
	strvec_push(&args, "--exclude-guides");  // argv[1]
	strvec_push(&args, argv[0]);  // argv[2]
	argv = args.v;
	argc = 3;  // update based on the amount of pushs we did

Now no matter how many arguments we pass after
the --help, the results will always stay the same:

	"git commit --help foo-hello-world"
	"git commit --help pull -i -f"
	"git commit --help -i"
	|
	v
	"git help --exclude-guides commit"

Signed-off-by: Daniel Sonbolian <[e-mail]>
---
    git.c: fix, passing options after --help
    
    Since commit c6b6d9f7d8a when passing --help option to a Git command, we
    try to open that command man page, we do it for both commands and
    concepts, it is done by converting the entered command to a help command
    for the given Git command, for example:
    
    "git commit --help -i" into "git help --exclude-guides commit -i"
    
    
    But the options after --help option are also passed to the new command
    (-i option from the example) which can lead to unexpected output,
    because the help command will try to execute those extra options.
    
    This fixed by building the argv statically, meaning instead of switching
    places between argv arguments and then passing all the arguments to a
    new memory vector that will later be used as the new argv, we directly
    passing that memory vector only the required arguments and in the
    correct order, after that we also updating the argc to a static number:
    
    strvec_push(&args, "help");  // argv[0]
    strvec_push(&args, "--exclude-guides");  // argv[1]
    strvec_push(&args, argv[0]);  // argv[2]
    argv = args.v;
    argc = 3;  // update based on the amount of pushs we did
    
    
    Now no matter how many arguments we pass after the --help, the results
    will always stay the same:
    
    "git commit --help foo-hello-world"
    "git commit --help pull -i -f"
    "git commit --help -i"
    |
    v
    "git help --exclude-guides commit"
    
    
    Signed-off-by: Daniel Sonbolian [e-mail]

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1357%2Fdsal3389%2Fcmd-help-tweaks-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1357/dsal3389/cmd-help-tweaks-v1
Pull-Request: https://github.com/git/git/pull/1357

 git.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)


base-commit: 3dcec76d9df911ed8321007b1d197c1a206dc164

Comments

Junio C Hamano Oct. 10, 2022, 6:58 p.m. UTC | #1

"Daniel Sonbolian via GitGitGadget" <[e-mail]> writes:

> From: Daniel Sonbolian <[e-mail]>
>
> Since commit c6b6d9f7d8a when passing --help option

When referring to an old work, use

    $(git show -s --pretty=reference $that_commit)

I suspect that 2c6b6d9f (help: make option --help open man pages
only for Git commands, 2016-08-26) is what you meant (the author
CC'ed).

> to a Git command, we try to open that command man page, we
> do it for both commands and concepts, it is done by
> converting the entered command to a help command
> for the given Git command, for example:
>
> 	"git commit --help -i" into "git help --exclude-guides commit -i"
>
> But the options after --help option are also
> passed to the new command (-i option from the example)

"new command" meaning the "git help" command?

> which can lead to unexpected output, because the
> help command will try to execute those extra options.

Meaning "git commit --help -i" becomes "git help ... commit -i", and
because the command line parser of "git help" accepts dashed options
after "commit", it works just like "git help ... -i commit" does?

It is a request to read the help information for "git commit" using
the "--info" backend, right?  Similarly, "git commit --help -m"
would do the manpage and "git commit --help -w" would show the
manpage in the browser?

It sounds like a sensible behaviour to me (even though relying on
the behaviour of "git help" that takes dashed options after "commit"
makes me feel somewhat dirty).  So ...

> This fixed by building the argv statically, meaning

... I am not sure what you are fixing.  Puzzled...

Patch

diff --git a/git.c b/git.c
index da411c53822..75dcefa534d 100644
--- a/git.c
+++ b/git.c
@@ -697,25 +697,19 @@  static void handle_builtin(int argc, const char **argv)
 	struct cmd_struct *builtin;
 
 	strip_extension(argv);
-	cmd = argv[0];
 
 	/* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 	if (argc > 1 && !strcmp(argv[1], "--help")) {
-		int i;
-
-		argv[1] = argv[0];
-		argv[0] = cmd = "help";
-
-		for (i = 0; i < argc; i++) {
-			strvec_push(&args, argv[i]);
-			if (!i)
-				strvec_push(&args, "--exclude-guides");
-		}
+		strvec_push(&args, "help");
+		strvec_push(&args, "--exclude-guides");
+		strvec_push(&args, argv[0]);
 
-		argc++;
 		argv = args.v;
+		argc = 3;
 	}
 
+	cmd = argv[0];
+
 	builtin = get_builtin(cmd);
 	if (builtin)
 		exit(run_builtin(builtin, argc, argv));