[PATCH v3 10/12] get_short_oid / peel_onion: ^{commit} should be commit, not committish

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change the ^{commit} syntax to mean just commits instead of committish
for the purpose of disambiguation. Before this e8f2^{commit} would
show the v2.17.0 tag as a disambiguation candidate, but now it'll just
show ambiguous commits:

    $ git rev-parse e8f2^{commit}
    error: short SHA1 e8f2 is ambiguous
    hint: The candidates are:
    hint:   e8f21caf94 commit 2013-06-24 - bash prompt: print unique detached HEAD abbreviated object name
    hint:   e8f26250fa commit 2017-02-03 - Merge pull request #996 from jeffhostetler/jeffhostetler/register_rename_src
    hint:   e8f2bc0c06 commit 2015-05-10 - Documentation: note behavior for multiple remote.url entries
    [...]

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 sha1-name.c                         | 2 +-
 t/t1512-rev-parse-disambiguation.sh | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/sha1-name.c b/sha1-name.c
index b61c0558d9..1d2a74a29c 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -966,7 +966,7 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 
 	lookup_flags &= ~GET_OID_DISAMBIGUATORS;
 	if (expected_type == OBJ_COMMIT)
-		lookup_flags |= GET_OID_COMMITTISH;
+		lookup_flags |= GET_OID_COMMIT;
 	else if (expected_type == OBJ_TAG)
 		lookup_flags |= GET_OID_TAG;
 	else if (expected_type == OBJ_TREE)
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index 81076449a2..b17973a266 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -341,8 +341,8 @@ test_expect_success C_LOCALE_OUTPUT 'ambiguity hints' '
 test_expect_success C_LOCALE_OUTPUT 'ambiguity hints respect type' '
 	test_must_fail git rev-parse 000000000^{commit} 2>stderr &&
 	grep ^hint: stderr >hints &&
-	# 5 commits, 1 tag (which is a commitish), plus intro line
-	test_line_count = 7 hints &&
+	# 5 commits plus intro line
+	test_line_count = 6 hints &&
 	git rev-parse 000000000^{tag} >stdout &&
 	test_line_count = 1 stdout &&
 	grep -q ^0000000000f8f stdout &&
@@ -366,7 +366,8 @@ test_expect_success 'core.disambiguate config can prefer types' '
 	# ambiguous between tree and tag
 	sha1=0000000000f &&
 	test_must_fail git rev-parse $sha1 &&
-	git rev-parse $sha1^{commit} &&
+	# there is no commit so ^{commit} comes up empty
+	test_must_fail git rev-parse $sha1^{commit} &&
 	git -c core.disambiguate=committish rev-parse $sha1
 '
 
-- 
2.17.0.290.gded63e768a