[PATCH 2/2] rebase --recreate-merges --keep-empty: don't prune empty commits

[Phillip Wood <phillip.wood@talktalk.net>]

From: Phillip Wood <phillip.wood@dunelm.org.uk>

If there are empty commits on the left hand side of $upstream...HEAD
then the empty commits on the right hand side that we want to keep are
pruned because they are marked as cherry-picks. Fix this by keeping
the commits that are empty or are not marked as cherry-picks.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 sequencer.c                       | 30 ++++++++++++++++--------------
 t/t3421-rebase-topology-linear.sh |  4 ++--
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index d8cc63dbe4..da87c390ed 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -2975,14 +2975,15 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 	 */
 	while ((commit = get_revision(revs))) {
 		struct commit_list *to_merge;
-		int is_octopus;
+		int is_octopus, is_empty;
 		const char *p1, *p2;
 		struct object_id *oid;
 
 		tail = &commit_list_insert(commit, tail)->next;
 		oidset_insert(&interesting, &commit->object.oid);
 
-		if ((commit->object.flags & PATCHSAME))
+		is_empty = is_original_commit_empty(commit);
+		if (!is_empty && (commit->object.flags & PATCHSAME))
 			continue;
 
 		strbuf_reset(&oneline);
@@ -2992,7 +2993,7 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 		if (!to_merge) {
 			/* non-merge commit: easy case */
 			strbuf_reset(&buf);
-			if (!keep_empty && is_original_commit_empty(commit))
+			if (!keep_empty && is_empty)
 				strbuf_addf(&buf, "%c ", comment_line_char);
 			strbuf_addf(&buf, "%s %s %s", cmd_pick,
 				    oid_to_hex(&commit->object.oid),
@@ -3172,12 +3173,9 @@ int sequencer_make_script(FILE *out, int argc, const char **argv,
 
 	init_revisions(&revs, NULL);
 	revs.verbose_header = 1;
-	if (recreate_merges)
-		revs.cherry_mark = 1;
-	else {
+	if (!recreate_merges)
 		revs.max_parents = 1;
-		revs.cherry_pick = 1;
-	}
+	revs.cherry_mark = 1;
 	revs.limited = 1;
 	revs.reverse = 1;
 	revs.right_only = 1;
@@ -3205,14 +3203,18 @@ int sequencer_make_script(FILE *out, int argc, const char **argv,
 		return make_script_with_merges(&pp, &revs, out, flags);
 
 	while ((commit = get_revision(&revs))) {
+		int is_empty  = is_original_commit_empty(commit);
+
 		strbuf_reset(&buf);
-		if (!keep_empty && is_original_commit_empty(commit))
+		if (!keep_empty && is_empty)
 			strbuf_addf(&buf, "%c ", comment_line_char);
-		strbuf_addf(&buf, "%s %s ", insn,
-			    oid_to_hex(&commit->object.oid));
-		pretty_print_commit(&pp, commit, &buf);
-		strbuf_addch(&buf, '\n');
-		fputs(buf.buf, out);
+		if (is_empty || !(commit->object.flags & PATCHSAME)) {
+			strbuf_addf(&buf, "%s %s ", insn,
+				    oid_to_hex(&commit->object.oid));
+			pretty_print_commit(&pp, commit, &buf);
+			strbuf_addch(&buf, '\n');
+			fputs(buf.buf, out);
+		}
 	}
 	strbuf_release(&buf);
 	return 0;
diff --git a/t/t3421-rebase-topology-linear.sh b/t/t3421-rebase-topology-linear.sh
index cb7f176f1d..7384010075 100755
--- a/t/t3421-rebase-topology-linear.sh
+++ b/t/t3421-rebase-topology-linear.sh
@@ -215,9 +215,9 @@ test_run_rebase () {
 }
 test_run_rebase success ''
 test_run_rebase failure -m
-test_run_rebase failure -i
+test_run_rebase success -i
 test_run_rebase failure -p
-test_run_rebase failure --recreate-merges
+test_run_rebase success --recreate-merges
 
 #       m
 #      /
-- 
2.16.2