[PATCH v19 4/7] branch: prepare delete_branches for a bulk caller

["Harald Nordgren via GitGitGadget" <gitgitgadget@gmail.com>]

From: Harald Nordgren <haraldnordgren@gmail.com>

Teach delete_branches() a new mode for the upcoming --delete-merged
caller that checks whether a branch is merged into its upstream without
falling back to HEAD when there is no upstream. Existing callers keep
their current behavior.

Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
---
 builtin/branch.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/builtin/branch.c b/builtin/branch.c
index 568ae817d6..23b2b7107c 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -168,10 +168,13 @@ static int branch_merged(int kind, const char *name,
 	 * upstream, if any, otherwise with HEAD", we should just
 	 * return the result of the repo_in_merge_bases() above without
 	 * any of the following code, but during the transition period,
-	 * a gentle reminder is in order.
+	 * a gentle reminder is in order.  Callers that opt out of the
+	 * HEAD fallback by passing head_rev=NULL are not interested in
+	 * the reminder either: they have already established that the
+	 * branch has an upstream, so HEAD is irrelevant to the decision.
 	 */
-	if (head_rev != reference_rev) {
-		int expect = head_rev ? repo_in_merge_bases(the_repository, rev, head_rev) : 0;
+	if (head_rev && head_rev != reference_rev) {
+		int expect = repo_in_merge_bases(the_repository, rev, head_rev);
 		if (expect < 0)
 			exit(128);
 		if (expect == merged)
@@ -193,6 +196,7 @@ enum delete_branch_flags {
 	DELETE_BRANCH_FORCE = (1 << 0),
 	DELETE_BRANCH_QUIET = (1 << 1),
 	DELETE_BRANCH_SKIP_UNMERGED = (1 << 2),
+	DELETE_BRANCH_NO_HEAD_FALLBACK = (1 << 3),
 };
 
 static int check_branch_commit(const char *branchname, const char *refname,
@@ -262,7 +266,8 @@ static int delete_branches(int argc, const char **argv, int kinds,
 	}
 	branch_name_pos = strcspn(fmt, "%");
 
-	if (!(flags & DELETE_BRANCH_FORCE))
+	if (!(flags & DELETE_BRANCH_FORCE) &&
+	    !(flags & DELETE_BRANCH_NO_HEAD_FALLBACK))
 		head_rev = lookup_commit_reference(the_repository, &head_oid);
 
 	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
-- 
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