Subject: [PATCH v3 08/12] get_short_oid: learn to disambiguate by ^{blob}

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Tue, 1 May 2018 18:40:12 +0000

The disambiguation logic had all the pieces necessary to only print
out those blobs that were ambiguous, but they hadn't been connected.

The initial logic was added in daba53aeaf ("sha1_name.c: add support
for disambiguating other types", 2012-07-02), and when the flags were
propagated in 8a10fea49b ("get_sha1: propagate flags to child
functions", 2016-09-26) GET_OID_BLOB wasn't added to lookup_flags.

Before this change requests for blobs were simply ignored:

    $ git rev-parse e8f2^{blob}
    error: short SHA1 e8f2 is ambiguous
    hint: The candidates are:
    hint:   e8f2650052 tag v2.17.0
    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
    hint:   e8f2093055 tree
    hint:   e8f25a3a50 tree
    hint:   e8f28d537c tree
    hint:   e8f2cf6ec0 tree
    hint:   e8f21d02f7 blob
    hint:   e8f21d577c blob
    hint:   e8f2867228 blob
    hint:   e8f2a35526 blob
    e8f2^{blob}
    [...]

But now we'll do the right thing and only print the blobs:

    $ git rev-parse e8f2^{blob}
    error: short SHA1 e8f2 is ambiguous
    hint: The candidates are:
    hint:   e8f21d02f7 blob
    hint:   e8f21d577c blob
    hint:   e8f2867228 blob
    hint:   e8f2a35526 blob
    e8f2^{blob}
    [...]

Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
---
 sha1-name.c                         | 2 ++
 t/t1512-rev-parse-disambiguation.sh | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/sha1-name.c b/sha1-name.c
index 68d5f65362..023f9471a8 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -971,6 +971,8 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 		lookup_flags |= GET_OID_TAG;
 	else if (expected_type == OBJ_TREE)
 		lookup_flags |= GET_OID_TREEISH;
+	else if (expected_type == OBJ_BLOB)
+		lookup_flags |= GET_OID_BLOB;
 
 	if (get_oid_1(name, sp - name - 2, &outer, lookup_flags))
 		return -1;
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index 74e7d9c178..9ce9cc3bc3 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -337,7 +337,11 @@ test_expect_success C_LOCALE_OUTPUT 'ambiguity hints respect type' '
 	test_line_count = 7 hints &&
 	git rev-parse 000000000^{tag} >stdout &&
 	test_line_count = 1 stdout &&
-	grep -q ^0000000000f8f stdout
+	grep -q ^0000000000f8f stdout &&
+	test_must_fail git rev-parse 000000000^{blob} 2>stderr &&
+	grep ^hint: stderr >hints &&
+	# 5 blobs plus intro line &&
+	test_line_count = 6 hints
 '
 
 test_expect_success C_LOCALE_OUTPUT 'failed type-selector still shows hint' '
-- 
2.17.0.290.gded63e768a