sha1_name.c: many short names can only be committish

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>

diff --git a/cache.h b/cache.h
index 2d91dbd958bd78b7580b535a8a5249470aa9acc0..1508fdb77a03b982167a1c3453ca92de514bb6e8 100644 (file)
--- 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 8feb9b553ae1cd3f52126314d49a55724dc5773f..215bb016f365036b55a5c94aedc738cc078c96ef 100644 (file)
--- 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 0d3f05b9926d3f9d7e18e78438d57b27d14cce96..7652f1c2e96c529fe6ee421fb544a3a48b16d135 100755 (executable)
--- 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 a2onsxbvj
 '
 
-test_expect_failure 'disambiguate commit-ish' '
+test_expect_success 'disambiguate commit-ish' '
        # feed commit-ish in an unambiguous way
        git rev-parse --verify 0000000000e4f^{commit} &&