merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 16 insertions, 5 deletions

diff --git a/third_party/git/ll-merge.c b/third_party/git/ll-merge.c
index 5b8d46aedee7..1ec0b959e015 100644
--- a/third_party/git/ll-merge.c
+++ b/third_party/git/ll-merge.c
@@ -32,6 +32,20 @@ struct ll_merge_driver {
 	char *cmdline;
 };
 
+static struct attr_check *merge_attributes;
+static struct attr_check *load_merge_attributes(void)
+{
+	if (!merge_attributes)
+		merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
+	return merge_attributes;
+}
+
+void reset_merge_attributes(void)
+{
+	attr_check_free(merge_attributes);
+	merge_attributes = NULL;
+}
+
 /*
  * Built-in low-levels
  */
@@ -233,7 +247,7 @@ static int read_merge_config(const char *var, const char *value, void *cb)
 {
 	struct ll_merge_driver *fn;
 	const char *key, *name;
-	int namelen;
+	size_t namelen;
 
 	if (!strcmp(var, "merge.default"))
 		return git_config_string(&default_ll_merge, var, value);
@@ -354,7 +368,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	     struct index_state *istate,
 	     const struct ll_merge_options *opts)
 {
-	static struct attr_check *check;
+	struct attr_check *check = load_merge_attributes();
 	static const struct ll_merge_options default_opts;
 	const char *ll_driver_name = NULL;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
@@ -369,9 +383,6 @@ int ll_merge(mmbuffer_t *result_buf,
 		normalize_file(theirs, path, istate);
 	}
 
-	if (!check)
-		check = attr_check_initl("merge", "conflict-marker-size", NULL);
-
 	git_check_attr(istate, path, check);
 	ll_driver_name = check->items[0].value;
 	if (check->items[1].value) {