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[PATCH v5 15/25] sha1_name.c: many short names can only be committish

From
Junio C Hamano <gitster@pobox.com>
Date
Jul 3, 2012, 21:37 UTC
Message-ID
<1341351435-31011-16-git-send-email-gitster@pobox.com>
In-Reply-To
<1341351435-31011-1-git-send-email-gitster@pobox.com>

We know that the token "$name" that appear in "$name^{commit}", "$name^4", "$name~4" etc. can only name a committish (either a commit or a tag that peels to a commit). Teach get_short_sha1() to take advantage of that knowledge when disambiguating an abbreviated SHA-1 given as an object name.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 cache.h                             |  1 +
 sha1_name.c                         | 32 ++++++++++++++++++++++++++++----
 t/t1512-rev-parse-disambiguation.sh |  2 +-
 3 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/cache.h b/cache.h
index 2d91dbd..1508fdb 100644
--- a/cache.h
+++ b/cache.h
@@ -813,6 +813,7 @@ struct object_context {
 
 #define GET_SHA1_QUIETLY 01
 #define GET_SHA1_COMMIT 02
+#define GET_SHA1_COMMITTISH 04
 
 extern int get_sha1(const char *str, unsigned char *sha1);
 extern void maybe_die_on_misspelt_object_name(const char *name, const char *prefix);
diff --git a/sha1_name.c b/sha1_name.c
index 8feb9b5..215bb01 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -224,6 +224,24 @@ static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unu
 	return kind == OBJ_COMMIT;
 }
 
+static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	struct object *obj;
+	int kind;
+
+	kind = sha1_object_info(sha1, NULL);
+	if (kind == OBJ_COMMIT)
+		return 1;
+	if (kind != OBJ_TAG)
+		return 0;
+
+	/* We need to do this the hard way... */
+	obj = deref_tag(lookup_object(sha1), NULL, 0);
+	if (obj && obj->type == OBJ_COMMIT)
+		return 1;
+	return 0;
+}
+
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  unsigned flags)
 {
@@ -261,6 +279,8 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 	memset(&ds, 0, sizeof(ds));
 	if (flags & GET_SHA1_COMMIT)
 		ds.fn = disambiguate_commit_only;
+	else if (flags & GET_SHA1_COMMITTISH)
+		ds.fn = disambiguate_committish_only;
 
 	find_short_object_filename(len, hex_pfx, &ds);
 	find_short_packed_object(len, bin_pfx, &ds);
@@ -440,7 +460,7 @@ static int get_parent(const char *name, int len,
 		      unsigned char *result, int idx)
 {
 	unsigned char sha1[20];
-	int ret = get_sha1_1(name, len, sha1, 0);
+	int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 	struct commit *commit;
 	struct commit_list *p;
 
@@ -473,7 +493,7 @@ static int get_nth_ancestor(const char *name, int len,
 	struct commit *commit;
 	int ret;
 
-	ret = get_sha1_1(name, len, sha1, 0);
+	ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 	if (ret)
 		return ret;
 	commit = lookup_commit_reference(sha1);
@@ -519,6 +539,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	unsigned char outer[20];
 	const char *sp;
 	unsigned int expected_type = 0;
+	unsigned lookup_flags = 0;
 	struct object *o;
 
 	/*
@@ -554,7 +575,10 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	else
 		return -1;
 
-	if (get_sha1_1(name, sp - name - 2, outer, 0))
+	if (expected_type == OBJ_COMMIT)
+		lookup_flags = GET_SHA1_COMMITTISH;
+
+	if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 		return -1;
 
 	o = parse_object(outer);
@@ -666,7 +690,7 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned l
 	if (!ret)
 		return 0;
 
-	return get_short_sha1(name, len, sha1, 0);
+	return get_short_sha1(name, len, sha1, lookup_flags);
 }
 
 /*
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index de45468..1a736b0 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -85,7 +85,7 @@ test_expect_success 'first commit' '
 	git commit -m d8znjge0
 '
 
-test_expect_failure 'disambiguate commit-ish' '
+test_expect_success 'disambiguate commit-ish' '
 	# feed commit-ish in an unambiguous way
 	git rev-parse --verify 1102198268^{commit} &&
 
-- 
1.7.11.1.229.g706c98f
Previous: Junio C HamanoNext: Junio C Hamano
Message 16 of 26 in “Extending the shelf-life of "git describe" output”
  1. 00/25 Extending the shelf-life of "git describe" outputJunio C Hamano, Jul 3, 2012
  2. 01/25 sha1_name.c: indentation fixJunio C Hamano, Jul 3, 2012
  3. 02/25 sha1_name.c: hide get_sha1_with_context_1() uglinessJunio C Hamano, Jul 3, 2012
  4. 03/25 sha1_name.c: get rid of get_sha1_with_mode_1()Junio C Hamano, Jul 3, 2012
  5. 04/25 sha1_name.c: get rid of get_sha1_with_mode()Junio C Hamano, Jul 3, 2012
  6. 05/25 sha1_name.c: clarify what "fake" is for in find_short_object_filename()Junio C Hamano, Jul 3, 2012
  7. 06/25 sha1_name.c: rename "now" to "current"Junio C Hamano, Jul 3, 2012
  8. 07/25 sha1_name.c: refactor find_short_packed_object()Junio C Hamano, Jul 3, 2012
  9. 08/25 sha1_name.c: correct misnamed "canonical" and "res"Junio C Hamano, Jul 3, 2012
  10. 09/25 sha1_name.c: restructure disambiguation of short namesJunio C Hamano, Jul 3, 2012
  11. 10/25 get_sha1(): fix error status regressionJunio C Hamano, Jul 3, 2012
  12. 11/25 sha1_name.c: allow get_short_sha1() to take other flagsJunio C Hamano, Jul 3, 2012
  13. 12/25 sha1_name.c: teach get_short_sha1() a commit-only optionJunio C Hamano, Jul 3, 2012
  14. 13/25 sha1_name.c: get_describe_name() by definition groks only commitsJunio C Hamano, Jul 3, 2012
  15. 14/25 sha1_name.c: get_sha1_1() takes lookup flagsJunio C Hamano, Jul 3, 2012
  16. 15/25 sha1_name.c: many short names can only be committishJunio C Hamano, Jul 3, 2012
  17. 16/25 sha1_name.c: teach lookup context to get_sha1_with_context()Junio C Hamano, Jul 3, 2012
  18. 17/25 sha1_name.c: introduce get_sha1_committish()Junio C Hamano, Jul 3, 2012
  19. 18/25 revision.c: allow handle_revision_arg() to take other flagsJunio C Hamano, Jul 3, 2012
  20. 19/25 revision.c: the "log" family, except for "show", takes committishJunio C Hamano, Jul 3, 2012
  21. 20/25 sha1_name.c: add support for disambiguating other typesJunio C Hamano, Jul 3, 2012
  22. 21/25 apply: --build-fake-ancestor expects blobsJunio C Hamano, Jul 3, 2012
  23. 22/25 commit-tree: the command wants a tree and commitsJunio C Hamano, Jul 3, 2012
  24. 23/25 reset: the command takes committishJunio C Hamano, Jul 3, 2012
  25. 24/25 rev-parse: A and B in "rev-parse A..B" refer to committishJunio C Hamano, Jul 3, 2012
  26. 25/25 rev-parse --disambiguate=<prefix>Junio C Hamano, Jul 3, 2012

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