merge: cleanup messages like commit

This change allows git-merge messages to be cleaned up with the
commit.cleanup configuration or --cleanup option, just like how
git-commit does it.

We also give git-pull the option of --cleanup so that it can also take
advantage of this change.

Finally, add testing to ensure that messages are properly cleaned up.
Note that some newlines that were added to the commit message were
removed so that if a file were read via -F, it would be copied
faithfully.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 43 insertions, 10 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index 5ce8946..e1f7b73 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -38,6 +38,7 @@
 #include "tag.h"
 #include "alias.h"
 #include "commit-reach.h"
+#include "wt-status.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -98,6 +99,9 @@ enum ff_type {
 
 static enum ff_type fast_forward = FF_ALLOW;
 
+static const char *cleanup_arg;
+static enum commit_msg_cleanup_mode cleanup_mode;
+
 static int option_parse_message(const struct option *opt,
 				const char *arg, int unset)
 {
@@ -249,6 +253,7 @@ static struct option builtin_merge_options[] = {
 		N_("perform a commit if the merge succeeds (default)")),
 	OPT_BOOL('e', "edit", &option_edit,
 		N_("edit message before committing")),
+	OPT_CLEANUP(&cleanup_arg),
 	OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
 	OPT_SET_INT_F(0, "ff-only", &fast_forward,
 		      N_("abort if fast-forward is not possible"),
@@ -612,6 +617,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		return git_config_string(&pull_twohead, k, v);
 	else if (!strcmp(k, "pull.octopus"))
 		return git_config_string(&pull_octopus, k, v);
+	else if (!strcmp(k, "commit.cleanup"))
+		return git_config_string(&cleanup_arg, k, v);
 	else if (!strcmp(k, "merge.renormalize"))
 		option_renormalize = git_config_bool(k, v);
 	else if (!strcmp(k, "merge.ff")) {
@@ -800,8 +807,13 @@ static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
 static const char merge_editor_comment[] =
 N_("Please enter a commit message to explain why this merge is necessary,\n"
    "especially if it merges an updated upstream into a topic branch.\n"
-   "\n"
-   "Lines starting with '%c' will be ignored, and an empty message aborts\n"
+   "\n");
+
+static const char scissors_editor_comment[] =
+N_("An empty message aborts the commit.\n");
+
+static const char no_scissors_editor_comment[] =
+N_("Lines starting with '%c' will be ignored, and an empty message aborts\n"
    "the commit.\n");
 
 static void write_merge_heads(struct commit_list *);
@@ -809,11 +821,19 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 {
 	struct strbuf msg = STRBUF_INIT;
 	strbuf_addbuf(&msg, &merge_msg);
-	strbuf_addch(&msg, '\n');
 	if (squash)
 		BUG("the control must not reach here under --squash");
-	if (0 < option_edit)
-		strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
+	if (0 < option_edit) {
+		strbuf_addch(&msg, '\n');
+		if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) {
+			wt_status_append_cut_line(&msg);
+			strbuf_commented_addf(&msg, "\n");
+		}
+		strbuf_commented_addf(&msg, _(merge_editor_comment));
+		strbuf_commented_addf(&msg, _(cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS ?
+			scissors_editor_comment :
+			no_scissors_editor_comment), comment_line_char);
+	}
 	if (signoff)
 		append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
 	write_merge_heads(remoteheads);
@@ -832,7 +852,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 		abort_commit(remoteheads, NULL);
 
 	read_merge_msg(&msg);
-	strbuf_stripspace(&msg, 0 < option_edit);
+	cleanup_message(&msg, cleanup_mode, 0);
 	if (!msg.len)
 		abort_commit(remoteheads, _("Empty commit message."));
 	strbuf_release(&merge_msg);
@@ -880,7 +900,6 @@ static int finish_automerge(struct commit *head,
 	parents = remoteheads;
 	if (!head_subsumed || fast_forward == FF_NO)
 		commit_list_insert(head, &parents);
-	strbuf_addch(&merge_msg, '\n');
 	prepare_to_commit(remoteheads);
 	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
 			&result_commit, NULL, sign_commit))
@@ -1301,6 +1320,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	}
 	resolve_undo_clear();
 
+	if (option_edit < 0)
+		option_edit = default_edit_option();
+
+	cleanup_mode = get_cleanup_mode(cleanup_arg, 0 < option_edit);
+
 	if (verbosity < 0)
 		show_diffstat = 0;
 
@@ -1386,9 +1410,6 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			fast_forward = FF_NO;
 	}
 
-	if (option_edit < 0)
-		option_edit = default_edit_option();
-
 	if (!use_strategies) {
 		if (!remoteheads)
 			; /* already up-to-date */
diff --git a/builtin/pull.c b/builtin/pull.c
index 33db889..5bf82b4 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -24,6 +24,7 @@
 #include "lockfile.h"
 #include "wt-status.h"
 #include "commit-reach.h"
+#include "sequencer.h"
 
 enum rebase_type {
 	REBASE_INVALID = -1,
@@ -101,6 +102,7 @@ static char *opt_signoff;
 static char *opt_squash;
 static char *opt_commit;
 static char *opt_edit;
+static char *cleanup_arg;
 static char *opt_ff;
 static char *opt_verify_signatures;
 static int opt_autostash = -1;
@@ -168,6 +170,7 @@ static struct option pull_options[] = {
 	OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
 		N_("edit message before committing"),
 		PARSE_OPT_NOARG),
+	OPT_CLEANUP(&cleanup_arg),
 	OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
 		N_("allow fast-forward"),
 		PARSE_OPT_NOARG),
@@ -644,6 +647,8 @@ static int run_merge(void)
 		argv_array_push(&args, opt_commit);
 	if (opt_edit)
 		argv_array_push(&args, opt_edit);
+	if (cleanup_arg)
+		argv_array_pushf(&args, "--cleanup=%s", cleanup_arg);
 	if (opt_ff)
 		argv_array_push(&args, opt_ff);
 	if (opt_verify_signatures)
@@ -875,6 +880,13 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 
+	if (cleanup_arg)
+		/*
+		 * this only checks the validity of cleanup_arg; we don't need
+		 * a valid value for use_editor
+		 */
+		get_cleanup_mode(cleanup_arg, 0);
+
 	parse_repo_refspecs(argc, argv, &repo, &refspecs);
 
 	if (!opt_ff)