Is "make check-docs" useful anymore?

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Tue, Sep 14 2021, Matthias Aßhauer via GitGitGadget wrote:

> From: =?UTF-8?q?Matthias=20A=C3=9Fhauer?= <mha1993@live.de>
>
> While 'git version' is probably the least complex git command,
> it is a non-experimental user-facing builtin command. As such
> it should have a help page.
>
> Both `git help` and `git version` can be called as options
> (`--help`/`--version`) that internally get converted to the
> corresponding command. Add a small paragraph to
> Documentation/git.txt describing how these two options
> interact with each other and link to this help page for the
> sub-options that `--version` can take. Well, currently there
> is only one sub-option, but that could potentially increase
> in future versions of Git.
>
> Signed-off-by: Matthias Aßhauer <mha1993@live.de>
> ---
>  Documentation/git-version.txt | 28 ++++++++++++++++++++++++++++
>  Documentation/git.txt         |  4 ++++
>  2 files changed, 32 insertions(+)
>  create mode 100644 Documentation/git-version.txt
>
> diff --git a/Documentation/git-version.txt b/Documentation/git-version.txt
> new file mode 100644
> index 00000000000..80fa7754a6d
> --- /dev/null
> +++ b/Documentation/git-version.txt
> @@ -0,0 +1,28 @@
> +git-version(1)
> +==============
> +
> +NAME
> +----
> +git-version - Display version information about Git
> +
> +SYNOPSIS
> +--------
> +[verse]
> +'git version' [--build-options]
> +
> +DESCRIPTION
> +-----------
> +With no options given, the version of 'git' is printed on the standard output.
> +
> +Note that `git --version` is identical to `git version` because the
> +former is internally converted into the latter.
> +
> +OPTIONS
> +-------
> +--build-options::
> +	Include additional information about how git was built for diagnostic
> +	purposes.
> +
> +GIT
> +---
> +Part of the linkgit:git[1] suite
> diff --git a/Documentation/git.txt b/Documentation/git.txt
> index 6dd241ef838..95fe6f31b4f 100644
> --- a/Documentation/git.txt
> +++ b/Documentation/git.txt
> @@ -41,6 +41,10 @@ OPTIONS
>  -------
>  --version::
>  	Prints the Git suite version that the 'git' program came from.
> ++
> +This option is internaly converted to `git version ...` and accepts
> +the same options as the linkgit:git-version[1] command. If `--help` is
> +also given, it takes precedence over `--version`.
>  
>  --help::
>  	Prints the synopsis and a list of the most commonly used

I didn't notice until after it hit master that this caused a regression
in "make check-docs":

    $ make -s check-docs
    removed but documented: git-version

The "fix" is rather easy, i.e. adding "git-version" to the whitelist.

But I wondered about $subject, i.e. we want to run the "lint" part, but
do we really need something reminding us that there isn't a mapping
between Documentation/*.txt and *.o files present at the top-level?

That whole part seems to have been some "reminder to document" addition
in 8c989ec5288 (Makefile: $(MAKE) check-docs, 2006-04-13).

If we're going to keep it in pretty much its current form then the CI
integration added in b98712b9aa9 (travis-ci: build documentation,
2016-05-04) seems rather useless when it comes to this, i.e. we should
either adjust it to exit non-zero, or check if we've got output under
"make -s" and fail the check then.