Merge branch 'jc/abbrev-guard'

* jc/abbrev-guard:
core.abbrevguard: Ensure short object names stay unique a bit longer

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 6b7279f88303e2d7a45baa27022cb9e53cf387be..ad5eb5f21d8cf3ea011f01a3b4bc8289877a1c89 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -374,6 +374,15 @@ core.warnAmbiguousRefs::
        If true, git will warn you if the ref name you passed it is ambiguous
        and might match multiple refs in the .git/refs/ tree. True by default.
 
+core.abbrevguard::
+       Even though git makes sure that it uses enough hexdigits to show
+       an abbreviated object name unambiguously, as more objects are
+       added to the repository over time, a short name that used to be
+       unique will stop being unique.  Git uses this many extra hexdigits
+       that are more than necessary to make the object name currently
+       unique, in the hope that its output will stay unique a bit longer.
+       Defaults to 0.
+
 core.compression::
        An integer -1..9, indicating a default compression level.
        -1 is the zlib default. 0 means no compression,

diff --git a/cache.h b/cache.h
index d85ce86f7fd72ee90553241316c1cf6d84a2898d..e56a0a23ae9e81ea4b691c6d365491a6ecb41f62 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -545,6 +545,7 @@ extern int assume_unchanged;
 extern int prefer_symlink_refs;
 extern int log_all_ref_updates;
 extern int warn_ambiguous_refs;
+extern int unique_abbrev_extra_length;
 extern int shared_repository;
 extern const char *apply_default_whitespace;
 extern const char *apply_default_ignorewhitespace;

diff --git a/config.c b/config.c
index c63d6834e087bbe2469cb285d3b3de475b76b972..f138c34721b4751f3e8b0a1d10680f70ebfa2741 100644 (file)
--- a/config.c
+++ b/config.c
@@ -489,6 +489,13 @@ static int git_default_core_config(const char *var, const char *value)
                return 0;
        }
 
+       if (!strcmp(var, "core.abbrevguard")) {
+               unique_abbrev_extra_length = git_config_int(var, value);
+               if (unique_abbrev_extra_length < 0)
+                       unique_abbrev_extra_length = 0;
+               return 0;
+       }
+
        if (!strcmp(var, "core.bare")) {
                is_bare_repository_cfg = git_config_bool(var, value);
                return 0;

diff --git a/environment.c b/environment.c
index de5581fe51d532231b0121bd2ef2e46669015bda..92e16b19b22ac6a973b3f7a9eab834a4d596b566 100644 (file)
--- a/environment.c
+++ b/environment.c
@@ -21,6 +21,7 @@ int prefer_symlink_refs;
 int is_bare_repository_cfg = -1; /* unspecified */
 int log_all_ref_updates = -1; /* unspecified */
 int warn_ambiguous_refs = 1;
+int unique_abbrev_extra_length;
 int repository_format_version;
 const char *git_commit_encoding;
 const char *git_log_output_encoding;

diff --git a/sha1_name.c b/sha1_name.c
index 3e856b80369c289a3d9399d60ec3be22bbbc6788..b48b91c507e597405274dc5aa3edc98ee5149bdc 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -206,7 +206,9 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
                if (exists
                    ? !status
                    : status == SHORT_NAME_NOT_FOUND) {
-                       hex[len] = 0;
+                       int cut_at = len + unique_abbrev_extra_length;
+                       cut_at = (cut_at < 40) ? cut_at : 40;
+                       hex[cut_at] = 0;
                        return hex;
                }
                len++;