Re: [PATCH v2] config: learn the "onbranch:" includeIf condition

> Currently, if a user wishes to have individual settings per branch, they
> are required to manually keep track of the settings in their head and
> manually set the options on the command-line or change the config at
> each branch.
>
> Teach config the "onbranch:" includeIf condition so that it can
> conditionally include configuration files if the branch that is checked
> out in the current worktree matches the pattern given.

> Signed-off-by: Denton Liu <liu.denton@gmail.com>
> ---
>
> Thanks for taking a look, Johannes. I've modified the patch to match
> with wildcards now.
>
> Changes since v1:
>
> * Allow onbranch: to specify a pattern instead of just a static
>   comparison
>
> Interdiff against v1:
>   diff --git a/Documentation/config.txt b/Documentation/config.txt
>   index 3b9fbe1860..93aa4323c6 100644
>   --- a/Documentation/config.txt
>   +++ b/Documentation/config.txt
>   @@ -145,9 +145,11 @@ refer to linkgit:gitignore[5] for details. For convenience:
>    	case-insensitively (e.g. on case-insensitive file sytems)
>
>    `onbranch`::
>   -	The data that follows the keyword `onbranch:` is taken to be a
>   -	name of a local branch. If we are in a worktree where that
>   -	branch is currently checked out, the include condition is met.
>   +	The data that follows the keyword `onbranch:` is taken to be a pattern
>   +	with standard globbing wildcards and two additional ones, `**/` and
>   +	`/**`, that can match multiple path components. If we are in a worktree
>   +	where the name of the branch that is currently checked out matches the
>   +	pattern, the include condition is met.
>
>    A few more notes on matching via `gitdir` and `gitdir/i`:
>
>   diff --git a/config.c b/config.c
>   index 954e84e13a..48bb435739 100644
>   --- a/config.c
>   +++ b/config.c
>   @@ -268,6 +268,8 @@ static int include_by_gitdir(const struct config_options *opts,
>    static int include_by_branch(const char *cond, size_t cond_len)
>    {
>    	int flags;
>   +	int ret;
>   +	struct strbuf pattern = STRBUF_INIT;
>    	const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, &flags);
>    	const char *shortname;
>
>   @@ -275,7 +277,10 @@ static int include_by_branch(const char *cond, size_t cond_len)
>    			!skip_prefix(refname, "refs/heads/", &shortname))
>    		return 0;
>
>   -	return !strncmp(cond, shortname, cond_len);
>   +	strbuf_add(&pattern, cond, cond_len);
>   +	ret = !wildmatch(pattern.buf, shortname, WM_PATHNAME);
>   +	strbuf_release(&pattern);
>   +	return ret;
>    }
>
>    static int include_condition_is_true(const struct config_options *opts,
>   diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
>   index 062db08ad9..05c7def1f2 100755
>   --- a/t/t1305-config-include.sh
>   +++ b/t/t1305-config-include.sh
>   @@ -314,6 +314,7 @@ test_expect_success 'conditional include, onbranch' '
>    		cd bar &&
>    		echo "[includeIf \"onbranch:foo-branch\"]path=bar9" >>.git/config &&
>    		echo "[test]nine=9" >.git/bar9 &&
>   +		git checkout -b master &&
>    		test_must_fail git config test.nine &&
>    		git checkout -b foo-branch &&
>    		echo 9 >expect &&
>   @@ -322,6 +323,25 @@ test_expect_success 'conditional include, onbranch' '
>    	)
>    '
>
>   +test_expect_success 'conditional include, onbranch, wildcard' '
>   +	(
>   +		cd bar &&
>   +		echo "[includeIf \"onbranch:?oo-*/**\"]path=bar10" >>.git/config &&
>   +		echo "[test]ten=10" >.git/bar10 &&
>   +		git checkout -b not-foo-branch/a &&
>   +		test_must_fail git config test.ten &&
>   +
>   +		echo 10 >expect &&
>   +		git checkout -b foo-branch/a/b/c &&
>   +		git config test.ten >actual &&
>   +		test_cmp expect actual &&
>   +
>   +		git checkout -b moo-bar/a &&
>   +		git config test.ten >actual &&
>   +		test_cmp expect actual
>   +	)
>   +'
>   +
>    test_expect_success 'include cycles are detected' '
>    	cat >.gitconfig <<-\EOF &&
>    	[test]value = gitconfig
>
>  Documentation/config.txt  | 12 ++++++++++++
>  config.c                  | 21 +++++++++++++++++++++
>  t/t1305-config-include.sh | 33 +++++++++++++++++++++++++++++++++
>  3 files changed, 66 insertions(+)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 7e2a6f61f5..93aa4323c6 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -144,6 +144,13 @@ refer to linkgit:gitignore[5] for details. For convenience:
>  	This is the same as `gitdir` except that matching is done
>  	case-insensitively (e.g. on case-insensitive file sytems)
>
> +`onbranch`::
> +	The data that follows the keyword `onbranch:` is taken to be a pattern
> +	with standard globbing wildcards and two additional ones, `**/` and
> +	`/**`, that can match multiple path components. If we are in a worktree
> +	where the name of the branch that is currently checked out matches the
> +	pattern, the include condition is met.
> +
>  A few more notes on matching via `gitdir` and `gitdir/i`:
>
>   * Symlinks in `$GIT_DIR` are not resolved before matching.
> @@ -206,6 +213,11 @@ Example
>  	[includeIf "gitdir:/path/to/group/"]
>  		path = foo.inc
>
> +	; include only if we are in a worktree where foo-branch is
> +	; currently checked out
> +	[includeIf "onbranch:foo-branch"]
> +		path = foo.inc
> +
>  Values
>  ~~~~~~
>
> diff --git a/config.c b/config.c
> index 296a6d9cc4..48bb435739 100644
> --- a/config.c
> +++ b/config.c
> @@ -19,6 +19,7 @@
>  #include "utf8.h"
>  #include "dir.h"
>  #include "color.h"
> +#include "refs.h"
>
>  struct config_source {
>  	struct config_source *prev;
> @@ -264,6 +265,24 @@ static int include_by_gitdir(const struct config_options *opts,
>  	return ret;
>  }
>
> +static int include_by_branch(const char *cond, size_t cond_len)
> +{
> +	int flags;
> +	int ret;
> +	struct strbuf pattern = STRBUF_INIT;
> +	const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, &flags);
> +	const char *shortname;
> +
> +	if (!refname || !(flags & REF_ISSYMREF)	||
> +			!skip_prefix(refname, "refs/heads/", &shortname))
> +		return 0;
> +
> +	strbuf_add(&pattern, cond, cond_len);
> +	ret = !wildmatch(pattern.buf, shortname, WM_PATHNAME);
> +	strbuf_release(&pattern);
> +	return ret;
> +}
> +
>  static int include_condition_is_true(const struct config_options *opts,
>  				     const char *cond, size_t cond_len)
>  {
> @@ -272,6 +291,8 @@ static int include_condition_is_true(const struct config_options *opts,
>  		return include_by_gitdir(opts, cond, cond_len, 0);
>  	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
>  		return include_by_gitdir(opts, cond, cond_len, 1);
> +	else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
> +		return include_by_branch(cond, cond_len);
>
>  	/* unknown conditionals are always false */
>  	return 0;
> diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
> index 579a86b7f8..05c7def1f2 100755
> --- a/t/t1305-config-include.sh
> +++ b/t/t1305-config-include.sh
> @@ -309,6 +309,39 @@ test_expect_success SYMLINKS 'conditional include, gitdir matching symlink, icas
>  	)
>  '
>
> +test_expect_success 'conditional include, onbranch' '
> +	(
> +		cd bar &&
> +		echo "[includeIf \"onbranch:foo-branch\"]path=bar9" >>.git/config &&
> +		echo "[test]nine=9" >.git/bar9 &&
> +		git checkout -b master &&
> +		test_must_fail git config test.nine &&
> +		git checkout -b foo-branch &&
> +		echo 9 >expect &&
> +		git config test.nine >actual &&
> +		test_cmp expect actual
> +	)
> +'
> +
> +test_expect_success 'conditional include, onbranch, wildcard' '
> +	(
> +		cd bar &&
> +		echo "[includeIf \"onbranch:?oo-*/**\"]path=bar10" >>.git/config &&
> +		echo "[test]ten=10" >.git/bar10 &&
> +		git checkout -b not-foo-branch/a &&
> +		test_must_fail git config test.ten &&
> +
> +		echo 10 >expect &&
> +		git checkout -b foo-branch/a/b/c &&
> +		git config test.ten >actual &&
> +		test_cmp expect actual &&
> +
> +		git checkout -b moo-bar/a &&
> +		git config test.ten >actual &&
> +		test_cmp expect actual
> +	)
> +'
> +
>  test_expect_success 'include cycles are detected' '
>  	cat >.gitconfig <<-\EOF &&
>  	[test]value = gitconfig
> --
> 2.22.0.rc1.169.g49223abbf8
>
>