[PATCHv2 2/2] branch: name detached HEAD analogous to status

[Michael J Gruber <git@drmicha.warpmail.net>]

"git status" carefully names a detached HEAD "at" resp. "from" a rev or
ref depending on whether the detached HEAD has moved since. "git branch"
always uses "from", which can be confusing, because a status-aware user
would interpret this as moved detached HEAD.

Make "git branch" use the same logic and wording.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---

Notes:
    v2 uses the info from refactored wt-status.
    
    In addition, it tries to make sure that branch and status use the same
    strings:
    
    HEAD detached at %s
    * (HEAD detached at %s)
    
    (status first line, branch second line)
    
    Unfortunately, status strings are broken into pieces, so this can
    be achieved by comments only.

 builtin/branch.c         | 13 ++++++++++---
 t/t3203-branch-output.sh | 39 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/builtin/branch.c b/builtin/branch.c
index d8949cb..4c54240 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -589,9 +589,16 @@ static char *get_head_description(void)
 	else if (state.bisect_in_progress)
 		strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
 			    state.branch);
-	else if (state.detached_from)
-		strbuf_addf(&desc, _("(detached from %s)"),
-			    state.detached_from);
+	else if (state.detached_from) {
+		/* TRANSLATORS: make sure these match _("HEAD detached at ")
+		   and _("HEAD detached from ") in wt-status.c */
+		if (state.detached_at)
+			strbuf_addf(&desc, _("(HEAD detached at %s)"),
+				state.detached_from);
+		else
+			strbuf_addf(&desc, _("(HEAD detached from %s)"),
+				state.detached_from);
+	}
 	else
 		strbuf_addstr(&desc, _("(no branch)"));
 	free(state.branch);
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index ba4f98e..f51d0f3 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -96,7 +96,7 @@ test_expect_success 'git branch -v pattern does not show branch summaries' '
 
 test_expect_success 'git branch shows detached HEAD properly' '
 	cat >expect <<EOF &&
-* (detached from $(git rev-parse --short HEAD^0))
+* (HEAD detached at $(git rev-parse --short HEAD^0))
   branch-one
   branch-two
   master
@@ -106,4 +106,41 @@ EOF
 	test_i18ncmp expect actual
 '
 
+test_expect_success 'git branch shows detached HEAD properly after moving' '
+	cat >expect <<EOF &&
+* (HEAD detached from $(git rev-parse --short HEAD))
+  branch-one
+  branch-two
+  master
+EOF
+	git reset --hard HEAD^1 &&
+	git branch >actual &&
+	test_i18ncmp expect actual
+'
+
+test_expect_success 'git branch shows detached HEAD properly from tag' '
+	cat >expect <<EOF &&
+* (HEAD detached at fromtag)
+  branch-one
+  branch-two
+  master
+EOF
+	git tag fromtag master &&
+	git checkout fromtag &&
+	git branch >actual &&
+	test_i18ncmp expect actual
+'
+
+test_expect_success 'git branch shows detached HEAD properly after moving from tag' '
+	cat >expect <<EOF &&
+* (HEAD detached from fromtag)
+  branch-one
+  branch-two
+  master
+EOF
+	git reset --hard HEAD^1 &&
+	git branch >actual &&
+	test_i18ncmp expect actual
+'
+
 test_done
-- 
2.3.1.303.g5174db1