[PATCH v2 1/3] config: add "worktree" and "worktree/i" includeIf conditions

[Chen Linxuan via B4 Relay <devnull+me.black-desk.cn@kernel.org>]

From: Chen Linxuan <me@black-desk.cn>

The `includeIf` mechanism already supports matching on the `.git`
directory path (`gitdir`) and the currently checked out branch
(`onbranch`).  But in multi-worktree setups the `.git` directory of a
linked worktree points into the main repository's `.git/worktrees/`
area, which makes `gitdir` patterns cumbersome when one wants to
include config based on the working tree's checkout path instead.

Introduce two new condition keywords:

  - `worktree:<pattern>` matches the realpath of the current worktree's
    working directory (i.e. `repo_get_work_tree()`) against a glob
    pattern.  This is the path returned by `git rev-parse
    --show-toplevel`.

  - `worktree/i:<pattern>` is the case-insensitive variant.

The implementation follows the same structure as `include_by_gitdir()`:
the worktree path is resolved via `strbuf_realpath()`, the condition
pattern is prepared with `prepare_include_condition_pattern()` (which
handles `~` expansion, `./` relative paths, `**/` prefix insertion and
trailing-`/` expansion), and matching is done with `wildmatch()`.  A
second attempt using `strbuf_add_absolute_path()` is performed to
handle symlinked paths.

The condition never matches in bare repositories (where there is no
worktree) or during early config reading (where no repository is
available).

Signed-off-by: Chen Linxuan <me@black-desk.cn>
---
 config.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/config.c b/config.c
index 156f2a24fa00..6d0c2d0725e4 100644
--- a/config.c
+++ b/config.c
@@ -235,23 +235,20 @@ static int prepare_include_condition_pattern(const struct key_value_info *kvi,
 	return 0;
 }
 
-static int include_by_gitdir(const struct key_value_info *kvi,
-			     const struct config_options *opts,
-			     const char *cond, size_t cond_len, int icase)
+static int include_by_path(const struct key_value_info *kvi,
+			   const char *path,
+			   const char *cond, size_t cond_len, int icase)
 {
 	struct strbuf text = STRBUF_INIT;
 	struct strbuf pattern = STRBUF_INIT;
 	size_t prefix;
 	int ret = 0;
-	const char *git_dir;
 	int already_tried_absolute = 0;
 
-	if (opts->git_dir)
-		git_dir = opts->git_dir;
-	else
+	if (!path)
 		goto done;
 
-	strbuf_realpath(&text, git_dir, 1);
+	strbuf_realpath(&text, path, 1);
 	strbuf_add(&pattern, cond, cond_len);
 	ret = prepare_include_condition_pattern(kvi, &pattern, &prefix);
 	if (ret < 0)
@@ -284,7 +281,7 @@ static int include_by_gitdir(const struct key_value_info *kvi,
 		 * which'll do the right thing
 		 */
 		strbuf_reset(&text);
-		strbuf_add_absolute_path(&text, git_dir);
+		strbuf_add_absolute_path(&text, path);
 		already_tried_absolute = 1;
 		goto again;
 	}
@@ -400,9 +397,15 @@ static int include_condition_is_true(const struct key_value_info *kvi,
 	const struct config_options *opts = inc->opts;
 
 	if (skip_prefix_mem(cond, cond_len, "gitdir:", &cond, &cond_len))
-		return include_by_gitdir(kvi, opts, cond, cond_len, 0);
+		return include_by_path(kvi, opts->git_dir, cond, cond_len, 0);
 	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
-		return include_by_gitdir(kvi, opts, cond, cond_len, 1);
+		return include_by_path(kvi, opts->git_dir, cond, cond_len, 1);
+	else if (skip_prefix_mem(cond, cond_len, "worktree:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 0);
+	else if (skip_prefix_mem(cond, cond_len, "worktree/i:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 1);
 	else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
 		return include_by_branch(inc, cond, cond_len);
 	else if (skip_prefix_mem(cond, cond_len, "hasconfig:remote.*.url:", &cond,

-- 
2.53.0