Re: [PATCH] git-prompt.sh: add submodule indicator

From: Stefan Beller <sbeller@google.com>
Date: Jan 20, 2017, 00:28 UTC
Message-ID: <CAGZ79kZNq=O=z-OSr-vDL4SUNViAUZ7AWz01TkGrmG88ZNqxgg@mail.gmail.com>
In-Reply-To: <1484870858-6336-1-git-send-email-email@benjaminfuchs.de>

On Thu, Jan 19, 2017 at 4:07 PM, Benjamin Fuchs <email@benjaminfuchs.de> wrote:

Show 6 quoted lines

> I expirienced that working with submodules can be confusing. This indicator
> will make you notice very easy when you switch into a submodule.
> The new prompt will look like this: (sub:master)
> Adding a new optional env variable for the new feature.
>
> Signed-off-by: Benjamin Fuchs <email@benjaminfuchs.de>

Thanks for making submodules better :) Relevant tangent, just posted today: https://public-inbox.org/git/20170119193023.26837-1-sbeller@google.com/T/#u

Show 33 quoted lines

> ---
>  contrib/completion/git-prompt.sh | 37 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
> index 97eacd7..4c82e7f 100644
> --- a/contrib/completion/git-prompt.sh
> +++ b/contrib/completion/git-prompt.sh
> @@ -93,6 +93,10 @@
>  # directory is set up to be ignored by git, then set
>  # GIT_PS1_HIDE_IF_PWD_IGNORED to a nonempty value. Override this on the
>  # repository level by setting bash.hideIfPwdIgnored to "false".
> +#
> +# If you would like __git_ps1 to indicate that you are in a submodule,
> +# set GIT_PS1_SHOWSUBMODULE. In this case a "sub:" will be added before
> +# the branch name.
>
>  # check whether printf supports -v
>  __git_printf_supports_v=
> @@ -284,6 +288,32 @@ __git_eread ()
>         test -r "$f" && read "$@" <"$f"
>  }
>
> +# __git_is_submodule
> +# Based on:
> +# http://stackoverflow.com/questions/7359204/git-command-line-know-if-in-submodule
> +__git_is_submodule ()
> +{
> +       local git_dir parent_git module_name path
> +       # Find the root of this git repo, then check if its parent dir is also a repo
> +       git_dir="$(git rev-parse --show-toplevel)"
> +       module_name="$(basename "$git_dir")"
> +       parent_git="$(cd "$git_dir/.." && git rev-parse --show-toplevel 2> /dev/null)"

I wonder if we want to have better plumbing commands for submodules here as well: Here we only check if we have an embedded git repository, which may not be a submodule. It could be a standalone repo that just happens to be inside another. It could be a fake submodule [1], though I think the last time I brought these up, the upstream Git community considered these fake submodules are bug not worth fixing.

And this doesn't cover the case that I addressed in the RFC-ish patch above:
  $ git submodule deinit --all
  $ cd <submodule> && git status
  # in an ideal world this tells you:
  #  "You are in an un-populated submodule. To change the submodule state..."

So I guess this is a good first approximation that actually gets most of the cases right, thereby helping a lot of people. But I wonder about these cornercases as well?

[1] debuggable.com/posts/git-fake-submodules:4b563ee4-f3cc-4061-967e-0e48cbdd56cb

Thanks, Stefan