Message-Id: <pull.2192.v4.git.1787221888406.gitgitgadget@gmail.com>
In-Reply-To: <pull.2192.git.1785852032626.gitgitgadget@gmail.com>
References: <pull.2192.git.1785852032626.gitgitgadget@gmail.com>
From: "Yoichi NAKAYAMA via GitGitGadget" <gitgitgadget@gmail.com>
Date: Thu, 20 Aug 2026 10:31:28 +0000
Subject: [PATCH v4] worktree add: shouldn't dwim if -b or -B is given
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To: git@vger.kernel.org
Cc: Jacob Abel <jacobabel@nullpo.dev>,
    Yoichi Nakayama <yoichi.nakayama@gmail.com>,
    Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>,
    Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>

From: Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>

'git worktree add <path> <branch>' DWIMs <branch> to a
remote-tracking branch when neither -b, -B, nor --detach
is given.

However, 'git worktree add -b <new-branch> <path> <branch>' can
still DWIM <branch>, causing <new-branch> to be ignored.  This is a
regression introduced by 128e5496b3 (worktree add: extend DWIM to
infer --orphan, 2023-05-17), which appeared in Git 2.42.

Signed-off-by: Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>
---
    worktree add: shouldn't dwim if -b or -B is given

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2192%2Fyoichi%2Fworktree-add-should-not-dwim-with-b-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2192/yoichi/worktree-add-should-not-dwim-with-b-v4
Pull-Request: https://github.com/gitgitgadget/git/pull/2192

Range-diff vs v3:

 1:  477ea27c8b ! 1:  512b037bb7 worktree add: shouldn't dwim if -b or -B is given
     @@ Commit message
          is given.
      
          However, 'git worktree add -b <new-branch> <path> <branch>' can
     -    still DWIM <branch>, causing <new-branch> to be ignored.
     -
     -    This is a regression introduced in v2.42.0
     -    (128e5496b325640f0a09cc1d5b1e346c069b410f).
     +    still DWIM <branch>, causing <new-branch> to be ignored.  This is a
     +    regression introduced by 128e5496b3 (worktree add: extend DWIM to
     +    infer --orphan, 2023-05-17), which appeared in Git 2.42.
      
          Signed-off-by: Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>
      
       ## builtin/worktree.c ##
      @@ builtin/worktree.c: static int add(int ac, const char **av, const char *prefix,
     + 
       		/* DWIM: Infer --orphan when repo has no refs. */
       		opts.orphan = (!s) && dwim_orphan(&opts, !!opt_track, 1);
     ++	} else if (ac == 2 && new_branch) {
     ++		if (!strcmp(branch, "HEAD"))
     ++			can_use_local_refs(&opts);
       	} else if (ac == 2) {
     --		struct object_id oid;
     --		struct commit *commit;
     --		char *remote;
     --
     --		commit = lookup_commit_reference_by_name(branch);
     --		if (!commit) {
     --			remote = unique_tracking_name(branch, &oid, NULL);
     --			if (remote) {
     --				new_branch = branch;
     --				branch = new_branch_to_free = remote;
     -+		if (!new_branch) {
     -+			struct object_id oid;
     -+			struct commit *commit;
     -+			char *remote;
     -+
     -+			commit = lookup_commit_reference_by_name(branch);
     -+			if (!commit) {
     -+				remote = unique_tracking_name(branch, &oid, NULL);
     -+				if (remote) {
     -+					new_branch = branch;
     -+					branch = new_branch_to_free = remote;
     -+				}
     - 			}
     - 		}
     - 
     + 		struct object_id oid;
     + 		struct commit *commit;
      
       ## t/t2400-worktree-add.sh ##
      @@ t/t2400-worktree-add.sh: test_expect_success '"add" <path> <branch> dwims' '


 builtin/worktree.c      |  3 +++
 t/t2400-worktree-add.sh | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index 654d27c3e1..15a1c9624a 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -897,6 +897,9 @@ static int add(int ac, const char **av, const char *prefix,
 
 		/* DWIM: Infer --orphan when repo has no refs. */
 		opts.orphan = (!s) && dwim_orphan(&opts, !!opt_track, 1);
+	} else if (ac == 2 && new_branch) {
+		if (!strcmp(branch, "HEAD"))
+			can_use_local_refs(&opts);
 	} else if (ac == 2) {
 		struct object_id oid;
 		struct commit *commit;
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index 87b926728a..ba3bec078f 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -621,6 +621,16 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> does not dwim with -b' '
+	test_when_finished rm -rf repo_upstream repo_dwim wt &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	(
+		cd repo_dwim &&
+		test_must_fail git worktree add -b branch ../wt foo 2>actual &&
+		test_grep "^fatal: invalid reference: foo" actual
+	)
+'
+
 test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
 	test_when_finished rm -rf repo_upstream repo_dwim foo &&
 	setup_remote_repo repo_upstream repo_dwim &&

base-commit: dea0ea3582e6980ddbc1173cc8e3e9f9db91cde0
-- 
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