[PATCH v3 2/4] history: give commit_tree_ext a message template

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

From: Harald Nordgren <haraldnordgren@gmail.com>

commit_tree_ext() reuses the message of the commit it is handed. A
caller that folds several commits together wants to seed the message
from more than that single commit, so add an optional message_template
parameter. When NULL, the behavior is unchanged.

Pass NULL from the existing fixup and split callers.

Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
---
 builtin/history.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/builtin/history.c b/builtin/history.c
index f95f26e684..305bde3102 100644
--- a/builtin/history.c
+++ b/builtin/history.c
@@ -101,6 +101,7 @@ enum commit_tree_flags {
 static int commit_tree_ext(struct repository *repo,
 			   const char *action,
 			   struct commit *commit_with_message,
+			   const char *message_template,
 			   const struct commit_list *parents,
 			   const struct object_id *old_tree,
 			   const struct object_id *new_tree,
@@ -130,13 +131,16 @@ static int commit_tree_ext(struct repository *repo,
 		original_author = xmemdupz(ptr, len);
 	find_commit_subject(original_message, &original_body);
 
+	if (!message_template)
+		message_template = original_body;
+
 	if (flags & COMMIT_TREE_EDIT_MESSAGE) {
 		ret = fill_commit_message(repo, old_tree, new_tree,
-					  original_body, action, &commit_message);
+					  message_template, action, &commit_message);
 		if (ret < 0)
 			goto out;
 	} else {
-		strbuf_addstr(&commit_message, original_body);
+		strbuf_addstr(&commit_message, message_template);
 	}
 
 	original_extra_headers = read_commit_extra_headers(commit_with_message,
@@ -189,7 +193,7 @@ static int commit_tree_with_edited_message(struct repository *repo,
 	if (first_parent_tree_oid(repo, original, &parent_tree_oid) < 0)
 		return -1;
 
-	return commit_tree_ext(repo, action, original, original->parents,
+	return commit_tree_ext(repo, action, original, NULL, original->parents,
 			       &parent_tree_oid, tree_oid, out, COMMIT_TREE_EDIT_MESSAGE);
 }
 
@@ -644,7 +648,7 @@ static int cmd_history_fixup(int argc,
 		goto out;
 
 	if (!skip_commit) {
-		ret = commit_tree_ext(repo, "fixup", original, original->parents,
+		ret = commit_tree_ext(repo, "fixup", original, NULL, original->parents,
 				      &original_tree->object.oid, &merge_result.tree->object.oid,
 				      &rewritten, flags);
 		if (ret < 0) {
@@ -855,7 +859,7 @@ static int split_commit(struct repository *repo,
 	 * The first commit is constructed from the split-out tree. The base
 	 * that shall be diffed against is the parent of the original commit.
 	 */
-	ret = commit_tree_ext(repo, "split-out", original, original->parents, &parent_tree_oid,
+	ret = commit_tree_ext(repo, "split-out", original, NULL, original->parents, &parent_tree_oid,
 			      &split_tree->object.oid, &first_commit, COMMIT_TREE_EDIT_MESSAGE);
 	if (ret < 0) {
 		ret = error(_("failed writing first commit"));
@@ -872,7 +876,7 @@ static int split_commit(struct repository *repo,
 	old_tree_oid = &repo_get_commit_tree(repo, first_commit)->object.oid;
 	new_tree_oid = &repo_get_commit_tree(repo, original)->object.oid;
 
-	ret = commit_tree_ext(repo, "split-out", original, parents, old_tree_oid,
+	ret = commit_tree_ext(repo, "split-out", original, NULL, parents, old_tree_oid,
 			      new_tree_oid, &second_commit, COMMIT_TREE_EDIT_MESSAGE);
 	if (ret < 0) {
 		ret = error(_("failed writing second commit"));
-- 
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