On Fri, Mar 6, 2026 at 8:15 AM VALERI Yoann via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> This patch adds a new configuration parameter for the branch creation
> feature: 'branch.namePrefix'. It corresponds to the '--name-prefix'
> option of 'git branch' made as configuration parameter, and behaves
> exactly like it.
>
> Signed-off-by: VALERI Yoann <yoann.valeri@cea.fr>
> ---
> diff --git a/Documentation/config/branch.adoc b/Documentation/config/branch.adoc
> @@ -35,6 +35,11 @@ This option defaults to `never`.
> +`branch.namePrefix`::
> +       When a new branch is created with `git branch`, use the provided value as
> +       prefix for its name. Can be '@{current}' to use the current branch's name
> +       as prefix.

This probably ought to mention --[no]-name-prefix to let the user know
that the configuration value can be overridden.

> diff --git a/branch.c b/branch.c
> @@ -368,18 +368,22 @@ int read_branch_desc(struct strbuf *buf, const char *branch_name)
>  void add_branch_prefix(const char *name_prefix,
>                                            const char *current_branch, struct strbuf *buf)
>  {
> -       int value = 0;
> +       char *config_prefix = NULL;
>
> -       if (!name_prefix)
> -               return;
> +       if (!name_prefix) {
> +               if (repo_config_get_string(the_repository, "branch.namePrefix",
> +                                                                  &config_prefix))
> +                       return;
>
> -       if (name_prefix[0] != '@') {
> -               strbuf_addstr(buf, name_prefix);
> -               return;
> +               name_prefix = config_prefix;
>         }
>
> -       if (strcmp(name_prefix, "@{current}") == 0)
> +       if (name_prefix[0] != '@')
> +               strbuf_addstr(buf, name_prefix);
> +       else if (strcmp(name_prefix, "@{current}") == 0)
>                 strbuf_addstr(buf, current_branch);
> +
> +    free(config_prefix);
>  }

This "diff" is very difficult to read because it's rewriting much of
the logic which was first introduced in patch [1/3]. When you reroll,
it would be a good idea to get the overall logic straight in patch
[1/3] so that subsequent patches only make small changes to it to
improve it (if necessary).

"VALERI Yoann via GitGitGadget" <gitgitgadget@gmail.com> writes:

> +`branch.namePrefix`::
> +	When a new branch is created with `git branch`, use the provided value as
> +	prefix for its name. Can be '@{current}' to use the current branch's name
> +	as prefix. This value can be overriden by using the '--[no-]name-prefix'
> +	option of `git branch`.

Even after reading the cover letter, I am not convinced why this is
a good idea in the first place.

Also, I am not sure if "current branch" really captures what you are
trying to achieve.  When "git branch foo" creates a new branch "foo"
out of _the_ _current_ branch, i.e.

    $ git checkout base
    $ git branch foo

with the nameprefix configuration, it may appear that it is doing
what you want by deriving the name of the new branch taking both
"base" and "foo" into account, but what would you want to happen if
you did this instead:

    $ git checkout base
    $ git branch foo

or while you may be on an unrelated "master" branch, create and
switch to the new branch:

    $ git checkout -b foo base

whose name takes both "base" and "foo" into account.

What I am getting at is that "the current branch" is missing the
point and it may be "the branch the new branch was forked off of"
that is what you really are trying to find that "base" in.

Having said all that, I am fairly negative on this new feature,
simply because it is too much magic and will be confusing,
especially when invoked with a configuration variable.

"VALERI Yoann via GitGitGadget" <gitgitgadget@gmail.com> writes:

> +test_expect_success 'create branch with config prefix' '
> +	test_config branch.autosetupmerge false &&
> +	test_config branch.namePrefix blob &&
> +	git branch -- -with-prefix &&
> +	test_ref_exists refs/heads/blob-with-prefix &&

Another thing I noticed.

Wouldn't you rather want to have a mechanism where the user does not
have to prefix the end-user supplied value ("with-prefix" in this
case) without leading dash?  From the look of what you are trying to
configure with the variable, the desire seems to be to allow the
user to make many branches that share the same prefix, so
conceptually, among blob-master, blob-maint, blob-feature branches
that would result in "git branch $name" where name is taken from the
vocabulary (master, maint, feature), the responsibility to supply
the word-separating hyphen belongs to either the prefix side (i.e.,
"blob-") or the mechanism that does prefising (i.e., the prefix
configuration @{current} comes up with a prefix string "blob", and
with the end-user supplied value of "with-prefix", the mechanism
that pastes these two strings makes the result "blob-with-prefix",
supplying the hyphen between "blob" and "with-prefix".

I said that I am negative in my previous message, simply because I
didn't get the intended use case at all, but even if there were a
good use case explained in future messages to make me change my
mind, I doubt that a design that requires the hyphen in front of
"with-prefix" the end-user is supposed to supply is a good thing to
have.

Thanks.

On Fri, Mar 6, 2026 at 8:15 AM VALERI Yoann via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> This patch adds a '--name-prefix' option to add a prefix to a newly
> created branch. It can use a regular string or a token as prefix. The
> only token currently handled is '@{current}', which is substituted for
> the current branch's name.
>
> Signed-off-by: VALERI Yoann <yoann.valeri@cea.fr>
> ---
> diff --git a/Documentation/git-branch.adoc b/Documentation/git-branch.adoc
> @@ -64,6 +65,10 @@ Note that this will create the new branch, but it will not switch the
> +With a `--name-prefix` option, you can add a prefix to the branch to create.
> +This can either a simple name, or a token. Currently, only '@{current}' is
> +managed as token, and will use the current branch name as prefix.

s/This can/& be/

> diff --git a/branch.c b/branch.c
> @@ -365,6 +365,23 @@ int read_branch_desc(struct strbuf *buf, const char *branch_name)
> +void add_branch_prefix(const char *name_prefix,
> +                                          const char *current_branch, struct strbuf *buf)
> +{
> +       int value = 0;

What is `value`? It doesn't seem to be used at all in this function.

> +       if (!name_prefix)
> +               return;
> +
> +       if (name_prefix[0] != '@') {
> +               strbuf_addstr(buf, name_prefix);
> +               return;
> +       }
> +
> +       if (strcmp(name_prefix, "@{current}") == 0)
> +               strbuf_addstr(buf, current_branch);
> +}

I would expect this function to produce some sort of diagnostic
warning when the user has given it a "@{token}" it doesn't recognize.

> diff --git a/branch.h b/branch.h
> @@ -148,6 +148,18 @@ int install_branch_config(int flag, const char *local, const char *origin, const
> +/*
> + * Store in 'buf' a prefix to the name of a branch to create by using the given
> + * string 'name_prefix'. It can either be a simple string to a shorthand
> + * starting with '@'.
> + *
> + * Currently, only '@{current}' is managed, and will use 'current_branch' as
> + * prefix.
> + */
> +void add_branch_prefix(const char *name_prefix, const char *current_branch,
> +                                          struct strbuf *buf);

It feels unnecessarily burdensome to force the caller to compute and
pass in `current_branch`. Intuitively, one would expect
add_branch_prefix() to compute the current branch itself if it
discovers that "@{current}" has been requested.

Moveover, this approach will not scale well when support for
additional "@{tokens}" is added down the road since it burdens *all*
callers with providing the values for *all* possible tokens.

> diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
> @@ -1716,4 +1716,22 @@ test_expect_success 'errors if given a bad branch name' '
> +test_expect_success 'create branch with --name-prefix' '
> +       git config branch.autosetupmerge false &&

Let's use `test_config` which will ensure that this setting is
reverted at the end of the test.


> +       git branch branch-with-prefix &&
> +       git branch --name-prefix "blob" -- -with-prefix &&
> +       test_must_fail git branch --name-prefix "blob" -- -with-prefix &&
> +       git branch --name-prefix "@{current}" -- -with-prefix &&
> +       git switch blob-with-prefix &&
> +       git branch --name-prefix "@{current}" -- -with-prefix &&
> +       test_must_fail git branch --name-prefix "@{current}" -- -with-prefix &&
> +       test_ref_exists refs/heads/branch-with-prefix &&
> +       test_ref_exists refs/heads/main-with-prefix &&
> +       test_ref_exists refs/heads/blob-with-prefix &&
> +       test_ref_exists refs/heads/blob-with-prefix-with-prefix &&
> +       git checkout main &&
> +       git branch -D branch-with-prefix main-with-prefix blob-with-prefix &&
> +       git branch -D blob-with-prefix-with-prefix
> +'

"VALERI Yoann via GitGitGadget" <gitgitgadget@gmail.com> writes:

> diff --git a/Documentation/git-branch.adoc b/Documentation/git-branch.adoc
> index c0afddc424..00967fa758 100644
> --- a/Documentation/git-branch.adoc
> +++ b/Documentation/git-branch.adoc
> @@ -17,7 +17,8 @@ git branch [--color[=<when>] | --no-color] [--show-current]
>  	   [(-r|--remotes) | (-a|--all)]
>  	   [--list] [<pattern>...]
>  git branch [--track[=(direct|inherit)] | --no-track] [-f]
> -	   [--recurse-submodules] <branch-name> [<start-point>]
> +	   [--recurse-submodules] [--name-prefix=<token>]
> +           <branch-name> [<start-point>]

The indentation of the last line seems a bit off; the previous line
uses leading HT both in the original and in the updated version, but
the last line uses SP indent.

> @@ -64,6 +65,10 @@ Note that this will create the new branch, but it will not switch the
>  working tree to it; use `git switch <new-branch>` to switch to the
>  new branch.
>  
> +With a `--name-prefix` option, you can add a prefix to the branch to create.
> +This can either a simple name, or a token. Currently, only '@{current}' is
> +managed as token, and will use the current branch name as prefix.

"can either" -> "can either be".
"managed" -> "supported".

> @@ -319,6 +324,10 @@ superproject's "origin/main", but tracks the submodule's "origin/main".
>  	and the object it points at.  _<format>_ is the same as
>  	that of linkgit:git-for-each-ref[1].
>  
> +`--name-prefix <token>`::
> +	A string that will be used as prefix to the name of the new branch to
> +        create. Can be '@{current}' to use the current branch's name.
> +
>  _<branch-name>_::
>  	The name of the branch to create or delete.
>  	The new branch name must pass all checks defined by
> diff --git a/branch.c b/branch.c
> index 243db7d0fc..c24d7ce823 100644
> --- a/branch.c
> +++ b/branch.c
> @@ -365,6 +365,23 @@ int read_branch_desc(struct strbuf *buf, const char *branch_name)
>  	return 0;
>  }
>  
> +void add_branch_prefix(const char *name_prefix,
> +					   const char *current_branch, struct strbuf *buf)

Overly deep indentation here.  Our tab-width is always 8, and you
would align the first "const char" on these two lines.

> +{
> +	int value = 0;

Unused variable?

> +	if (!name_prefix)
> +		return;
> +
> +	if (name_prefix[0] != '@') {
> +		strbuf_addstr(buf, name_prefix);
> +		return;
> +	}
> +
> +	if (strcmp(name_prefix, "@{current}") == 0)
> +		strbuf_addstr(buf, current_branch);
> +}

What happens when we need to support more than the @{current}?  Will
this function grow more parameters and the callers need to prepare
more parameters, even if only one of them may be picked by this
function?  That does not smell like a sound way to make things
maintainable.

> diff --git a/builtin/branch.c b/builtin/branch.c
> index c577b5d20f..58631913c7 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> ...
> +		add_branch_prefix(name_prefix, start_name, &new_branch_name);


Here, `start_name` is passed as `current_branch` to `add_branch_prefix`.
However, `start_name` is the `<start-point>` (e.g., another branch,
a tag, or a commit). If the user runs:

    $ git branch --name-prefix=@{current} new-branch other-branch

the prefix will be `other-branch` instead of the *current* branch
name as advertised in the documentation.  It _may_ be how the
feature was intended to work, but then the name "current" and the
way the documentation describes the token are both misleading.

> +			create_branch(the_repository, new_branch_name.buf, start_name,
> +						  force, 0, reflog, quiet, track, 0);

Overly deep indentation.