Merge branch 'tg/index-v4-format'

* tg/index-v4-format:
  read-cache: add index.version config variable
  test-lib: allow setting the index format version
  introduce GIT_INDEX_VERSION environment variable

1 files changed, 37 insertions, 1 deletions

diff --git a/read-cache.c b/read-cache.c
index fb440b4d9d..f23c44a81a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1220,6 +1220,42 @@ static struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
 
 #define INDEX_FORMAT_DEFAULT 3
 
+static int index_format_config(const char *var, const char *value, void *cb)
+{
+	unsigned int *version = cb;
+	if (!strcmp(var, "index.version")) {
+		*version = git_config_int(var, value);
+		return 0;
+	}
+	return 1;
+}
+
+static unsigned int get_index_format_default(void)
+{
+	char *envversion = getenv("GIT_INDEX_VERSION");
+	char *endp;
+	unsigned int version = INDEX_FORMAT_DEFAULT;
+
+	if (!envversion) {
+		git_config(index_format_config, &version);
+		if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
+			warning(_("index.version set, but the value is invalid.\n"
+				  "Using version %i"), INDEX_FORMAT_DEFAULT);
+			return INDEX_FORMAT_DEFAULT;
+		}
+		return version;
+	}
+
+	version = strtoul(envversion, &endp, 10);
+	if (*endp ||
+	    version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
+		warning(_("GIT_INDEX_VERSION set, but the value is invalid.\n"
+			  "Using version %i"), INDEX_FORMAT_DEFAULT);
+		version = INDEX_FORMAT_DEFAULT;
+	}
+	return version;
+}
+
 /*
  * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  * Again - this is just a (very strong in practice) heuristic that
@@ -1776,7 +1812,7 @@ int write_index(struct index_state *istate, int newfd)
 	}
 
 	if (!istate->version)
-		istate->version = INDEX_FORMAT_DEFAULT;
+		istate->version = get_index_format_default();
 
 	/* demote version 3 to version 2 when the latter suffices */
 	if (istate->version == 3 || istate->version == 2)