Re: [PATCH v6 4/7] checkout: describe_detached_head: remove ellipsis after committish

[Ann T Ropea <bedhanger@gmx.de>]

We do not want an ellipsis displayed following an (abbreviated) SHA-1
value.

The days when this was necessary to indicate the truncation to
lower-level Git commands and/or the user are bygone.

However, to ease the transition, the ellipsis will still be printed if
the user sets the environment variable GIT_PRINT_SHA1_ELLIPSIS to "yes".

Correct documentation with respect to what describe_detached_head prints
when GIT_PRINT_SHA1_ELLIPSIS is not set as indicated above.

Add tests for the old and new behaviour.

Signed-off-by: Ann T Ropea <bedhanger@gmx.de>
---
v2: rename patch series & focus on removal of ellipses
v3: env var instead of config option, use one-line comments where appropriate, preserve indent level
v4: improve env var handling (rename, helper func to query, docu)
v5: rewrite series to take Junio's comments in <xmqqd145k9td.fsf@gitster.mtv.corp.google.com> aboard
v6: polish to take Junio's comments from <xmqqshcqmoe7.fsf@gitster.mtv.corp.google.com> into account
 Documentation/user-manual.txt |   2 +-
 builtin/checkout.c            |  10 +++-
 t/t2020-checkout-detach.sh    | 114 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+), 3 deletions(-)

diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 497e82e88dd0..eff78902742a 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -319,7 +319,7 @@ do so (now or later) by using -b with the checkout command again. Example:
 
   git checkout -b new_branch_name
 
-HEAD is now at 427abfa... Linux v2.6.17
+HEAD is now at 427abfa Linux v2.6.17
 ------------------------------------------------
 
 The HEAD then refers to the SHA-1 of the commit instead of to a branch,
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 3faae382de4f..b0499542158f 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -400,10 +400,16 @@ static void show_local_changes(struct object *head,
 static void describe_detached_head(const char *msg, struct commit *commit)
 {
 	struct strbuf sb = STRBUF_INIT;
+
 	if (!parse_commit(commit))
 		pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
-	fprintf(stderr, "%s %s... %s\n", msg,
-		find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
+	if (print_sha1_ellipsis()) {
+		fprintf(stderr, "%s %s... %s\n", msg,
+			find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
+	} else {
+		fprintf(stderr, "%s %s %s\n", msg,
+			find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
+	}
 	strbuf_release(&sb);
 }
 
diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index fbb4ee9bb42d..3a37e07531ce 100755
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -186,4 +186,118 @@ test_expect_success 'no advice given for explicit detached head state' '
 	test_cmp expect.no-advice actual
 '
 
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (new format)
+test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not asked to' "
+
+	# The first detach operation is more chatty than the following ones.
+	cat 1>1st_detach <<'EOF' &&
+Note: checking out 'HEAD^'.
+
+You are in 'detached HEAD' state. You can look around, make experimental
+changes and commit them, and you can discard any commits you make in this
+state without impacting any branches by performing another checkout.
+
+If you want to create a new branch to retain commits you create, you may
+do so (now or later) by using -b with the checkout command again. Example:
+
+  git checkout -b <new-branch-name>
+
+HEAD is now at 7c7cd714e262 three
+EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat 1>2nd_detach <<'EOF' &&
+Previous HEAD position was 7c7cd714e262 three
+HEAD is now at 139b20d8e6c5 two
+EOF
+
+	cat 1>3rd_detach <<'EOF' &&
+Previous HEAD position was 139b20d8e6c5 two
+HEAD is now at d79ce1670bdc one
+EOF
+
+	reset && check_not_detached && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# Various ways of *not* asking for ellipses
+
+	sane_unset GIT_PRINT_SHA1_ELLIPSIS && git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS="no" git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS= git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# We only have four commits, but we can re-use them
+	reset && check_not_detached && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# Make no mention of the env var at all
+	git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS='nope' && export GIT_PRINT_SHA1_ELLIPSIS && git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=nein && export GIT_PRINT_SHA1_ELLIPSIS && git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	true
+"
+
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (old format)
+test_expect_success 'describe_detached_head does print SHA-1 ellipsis when asked to' "
+
+	# The first detach operation is more chatty than the following ones.
+	cat 1>1st_detach <<'EOF' &&
+Note: checking out 'HEAD^'.
+
+You are in 'detached HEAD' state. You can look around, make experimental
+changes and commit them, and you can discard any commits you make in this
+state without impacting any branches by performing another checkout.
+
+If you want to create a new branch to retain commits you create, you may
+do so (now or later) by using -b with the checkout command again. Example:
+
+  git checkout -b <new-branch-name>
+
+HEAD is now at 7c7cd714e262... three
+EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat 1>2nd_detach <<'EOF' &&
+Previous HEAD position was 7c7cd714e262... three
+HEAD is now at 139b20d8e6c5... two
+EOF
+
+	cat 1>3rd_detach <<'EOF' &&
+Previous HEAD position was 139b20d8e6c5... two
+HEAD is now at d79ce1670bdc... one
+EOF
+
+	reset && check_not_detached && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# Various ways of asking for ellipses...
+
+	GIT_PRINT_SHA1_ELLIPSIS="yes" && export GIT_PRINT_SHA1_ELLIPSIS && git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS='yes' git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=yes git -c 'core.abbrev=12' checkout HEAD^ 1>actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual && sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	true
+"
+
 test_done
-- 
2.13.6