Subject: Re: [PATCH] doc: remove mentions of .gitmodules !command syntax

From: Junio C Hamano <[email-masked]>
Date: Wed, 12 Jul 2023 09:40:24 -0700

[email-masked] writes:

> From: Petar Vutov <[email-masked]>
>
> To mitigate CVE-2019-19604, the capability to configure
> `git submodule update` to execute custom commands was
> removed in v2.20.2.
>
> The git-submodule documentation still mentions the now-unsupported
> syntax, which is misleading.
>
> Remove the leftover documentation.

The change during v2.20.2 timeperiod you have in mind may be
e904deb8 (submodule: reject submodule.update = !command in
.gitmodules, 2019-12-05).  The key phrase is "in .gitmodules"
as it did not forbid writing update command in the configuration.

The pre-context lines of your patch (see below) say that the 'custom
command' option and 'none' option are only available via the
`submodule.<name>.update` configuration variable.  IOW, this part of
the documentation does not talk about the .gitmodules file---it
talks about what you can say in the configuration file (which is
under your local control).

I think the existing text that came from fc01a5d2 (submodule update
documentation: don't repeat ourselves, 2016-12-27) may be
misleading, and may has room for improvement, but I do not think it
is wrong per-se.  If we remove it, there is nowhere else that teaches
users !cmd can be set in their configuration files, or is there?

Thanks.

> Signed-off-by: Petar Vutov <[email-masked]>
> ---
>  Documentation/git-submodule.txt | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
> index 4d3ab6b9f9..b40ac72f75 100644
> --- a/Documentation/git-submodule.txt
> +++ b/Documentation/git-submodule.txt
> @@ -163,12 +163,6 @@ checked out in the submodule.
>  The following 'update' procedures are only available via the
>  `submodule.<name>.update` configuration variable:
>  
> -	custom command;; arbitrary shell command that takes a single
> -	    argument (the sha1 of the commit recorded in the
> -	    superproject) is executed. When `submodule.<name>.update`
> -	    is set to '!command', the remainder after the exclamation mark
> -	    is the custom command.
> -
>  	none;; the submodule is not updated.
>  
>  If the submodule is not yet initialized, and you just want to use the