Merge branch 'jk/ambiguous-short-object-names'

When given an abbreviated object name that is not (or more
realistically, "no longer") unique, we gave a fatal error
"ambiguous argument".  This error is now accompanied by hints that
lists the objects that begins with the given prefix.  During the
course of development of this new feature, numerous minor bugs were
uncovered and corrected, the most notable one of which is that we
gave "short SHA1 xxxx is ambiguous." twice without good reason.

* jk/ambiguous-short-object-names:
  get_short_sha1: make default disambiguation configurable
  get_short_sha1: list ambiguous objects on error
  for_each_abbrev: drop duplicate objects
  sha1_array: let callbacks interrupt iteration
  get_short_sha1: mark ambiguity error for translation
  get_short_sha1: NUL-terminate hex prefix
  get_short_sha1: refactor init of disambiguation code
  get_short_sha1: parse tags when looking for treeish
  get_sha1: propagate flags to child functions
  get_sha1: avoid repeating ourselves via ONLY_TO_DIE
  get_sha1: detect buggy calls with multiple disambiguators

1 files changed, 7 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 6fc0e5ae6..1604e2987 100644
--- a/cache.h
+++ b/cache.h
@@ -1206,6 +1206,11 @@ struct object_context {
 #define GET_SHA1_FOLLOW_SYMLINKS 0100
 #define GET_SHA1_ONLY_TO_DIE    04000
 
+#define GET_SHA1_DISAMBIGUATORS \
+	(GET_SHA1_COMMIT | GET_SHA1_COMMITTISH | \
+	GET_SHA1_TREE | GET_SHA1_TREEISH | \
+	GET_SHA1_BLOB)
+
 extern int get_sha1(const char *str, unsigned char *sha1);
 extern int get_sha1_commit(const char *str, unsigned char *sha1);
 extern int get_sha1_committish(const char *str, unsigned char *sha1);
@@ -1220,6 +1225,8 @@ extern int get_oid(const char *str, struct object_id *oid);
 typedef int each_abbrev_fn(const unsigned char *sha1, void *);
 extern int for_each_abbrev(const char *prefix, each_abbrev_fn, void *);
 
+extern int set_disambiguate_hint_config(const char *var, const char *value);
+
 /*
  * Try to read a SHA1 in hexadecimal format from the 40 characters
  * starting at hex.  Write the 20-byte result to sha1 in binary form.