ref-filter: use correct branch for %(push:track)

In ref-filter.c, when processing the atom %(push:track), the
ahead/behind values are computed using `stat_tracking_info` which refers
to the upstream branch.

Fix that by introducing a new flag `for_push` in `stat_tracking_info`
in remote.c, which does the same thing but for the push branch.
Update the few callers of `stat_tracking_info` to handle this flag. This
ensure that whenever we use this function in the future, we are careful
to specify is this should apply to the upstream or the push branch.

This bug was not detected in t/t6300-for-each-ref.sh because in the test
for push:track, both the upstream and the push branches were behind by 1
from the local branch. Change the test so that the upstream branch is
behind by 1 while the push branch is ahead by 1. This allows us to test
that %(push:track) refers to the correct branch.

This changes the expected value of some following tests (by introducing
new references), so update them too.

Signed-off-by: Damien Robert <damien.olivier.robert+git@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 47 insertions, 21 deletions

diff --git a/remote.c b/remote.c
index 9cc3b07..0761d1a 100644
--- a/remote.c
+++ b/remote.c
@@ -1880,37 +1880,27 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
 }
 
 /*
- * Lookup the upstream branch for the given branch and if present, optionally
- * compute the commit ahead/behind values for the pair.
+ * Compute the commit ahead/behind values for the pair branch_name, base.
  *
  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
  * set to zero).
  *
- * The name of the upstream branch (or NULL if no upstream is defined) is
- * returned via *upstream_name, if it is not itself NULL.
- *
- * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
- * upstream defined, or ref does not exist).  Returns 0 if the commits are
- * identical.  Returns 1 if commits are different.
+ * Returns -1 if num_ours and num_theirs could not be filled in (e.g., ref
+ * does not exist).  Returns 0 if the commits are identical.  Returns 1 if
+ * commits are different.
  */
-int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
-		       const char **upstream_name, enum ahead_behind_flags abf)
+
+static int stat_branch_pair(const char *branch_name, const char *base,
+			     int *num_ours, int *num_theirs,
+			     enum ahead_behind_flags abf)
 {
 	struct object_id oid;
 	struct commit *ours, *theirs;
 	struct rev_info revs;
-	const char *base;
 	struct argv_array argv = ARGV_ARRAY_INIT;
 
-	/* Cannot stat unless we are marked to build on top of somebody else. */
-	base = branch_get_upstream(branch, NULL);
-	if (upstream_name)
-		*upstream_name = base;
-	if (!base)
-		return -1;
-
 	/* Cannot stat if what we used to build on no longer exists */
 	if (read_ref(base, &oid))
 		return -1;
@@ -1918,7 +1908,7 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 	if (!theirs)
 		return -1;
 
-	if (read_ref(branch->refname, &oid))
+	if (read_ref(branch_name, &oid))
 		return -1;
 	ours = lookup_commit_reference(the_repository, &oid);
 	if (!ours)
@@ -1932,7 +1922,7 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 	if (abf == AHEAD_BEHIND_QUICK)
 		return 1;
 	if (abf != AHEAD_BEHIND_FULL)
-		BUG("stat_tracking_info: invalid abf '%d'", abf);
+		BUG("stat_branch_pair: invalid abf '%d'", abf);
 
 	/* Run "rev-list --left-right ours...theirs" internally... */
 	argv_array_push(&argv, ""); /* ignored */
@@ -1967,6 +1957,42 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 }
 
 /*
+ * Lookup the tracking branch for the given branch and if present, optionally
+ * compute the commit ahead/behind values for the pair.
+ *
+ * If for_push is true, the tracking branch refers to the push branch,
+ * otherwise it refers to the upstream branch.
+ *
+ * The name of the tracking branch (or NULL if it is not defined) is
+ * returned via *tracking_name, if it is not itself NULL.
+ *
+ * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
+ * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
+ * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
+ * set to zero).
+ *
+ * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
+ * upstream defined, or ref does not exist).  Returns 0 if the commits are
+ * identical.  Returns 1 if commits are different.
+ */
+int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
+		       const char **tracking_name, int for_push,
+		       enum ahead_behind_flags abf)
+{
+	const char *base;
+
+	/* Cannot stat unless we are marked to build on top of somebody else. */
+	base = for_push ? branch_get_push(branch, NULL) :
+		branch_get_upstream(branch, NULL);
+	if (tracking_name)
+		*tracking_name = base;
+	if (!base)
+		return -1;
+
+	return stat_branch_pair(branch->refname, base, num_ours, num_theirs, abf);
+}
+
+/*
  * Return true when there is anything to report, otherwise false.
  */
 int format_tracking_info(struct branch *branch, struct strbuf *sb,
@@ -1977,7 +2003,7 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb,
 	char *base;
 	int upstream_is_gone = 0;
 
-	sti = stat_tracking_info(branch, &ours, &theirs, &full_base, abf);
+	sti = stat_tracking_info(branch, &ours, &theirs, &full_base, 0, abf);
 	if (sti < 0) {
 		if (!full_base)
 			return 0;