Merge branch 'rr/fmt-merge-msg'

* rr/fmt-merge-msg:
  t6200-fmt-merge-msg: Exercise '--log' to configure shortlog length
  t6200-fmt-merge-msg: Exercise 'merge.log' to configure shortlog length
  merge: Make 'merge.log' an integer or boolean option
  merge: Make '--log' an integer option for number of shortlog entries
  fmt_merge_msg: Change fmt_merge_msg API to accept shortlog_len

Conflicts:
	builtin/merge.c

Documentation/git-fmt-merge-msg.txt

@@ -9,8 +9,8 @@ git-fmt-merge-msg - Produce a merge commit message
 SYNOPSIS
 --------
 [verse]
-'git fmt-merge-msg' [-m <message>] [--log | --no-log] <$GIT_DIR/FETCH_HEAD
-'git fmt-merge-msg' [-m <message>] [--log | --no-log] -F <file>
+'git fmt-merge-msg' [-m <message>] [--log[=<n>] | --no-log] <$GIT_DIR/FETCH_HEAD
+'git fmt-merge-msg' [-m <message>] [--log[=<n>] | --no-log] -F <file>
 
 DESCRIPTION
 -----------
@@ -24,10 +24,12 @@ automatically invoking 'git merge'.
 OPTIONS
 -------
 
---log::
+--log[=<n>]::
 	In addition to branch names, populate the log message with
 	one-line descriptions from the actual commits that are being
-	merged.
+	merged.  At most <n> commits from each merge parent will be
+	used (20 if <n> is omitted).  This overrides the `merge.log`
+	configuration variable.
 
 --no-log::
 	Do not list one-line descriptions from the actual commits being
@@ -52,8 +54,10 @@ CONFIGURATION
 -------------
 
 merge.log::
-	Whether to include summaries of merged commits in newly
-	merge commit messages. False by default.
+	In addition to branch names, populate the log message with at
+	most the specified number of one-line descriptions from the
+	actual commits that are being merged.  Defaults to false, and
+	true is a synoym for 20.
 
 merge.summary::
 	Synonym to `merge.log`; this is deprecated and will be removed in

Documentation/merge-config.txt

@@ -7,8 +7,10 @@ merge.conflictstyle::
 	marker and the original text before the `=======` marker.
 
 merge.log::
-	Whether to include summaries of merged commits in newly created
-	merge commit messages. False by default.
+	In addition to branch names, populate the log message with at
+	most the specified number of one-line descriptions from the
+	actual commits that are being merged.  Defaults to false, and
+	true is a synoym for 20.
 
 merge.renameLimit::
 	The number of files to consider when performing rename detection

Documentation/merge-options.txt

@@ -16,11 +16,11 @@ inspect and further tweak the merge result before committing.
 With --no-ff Generate a merge commit even if the merge
 resolved as a fast-forward.
 
---log::
+--log[=<n>]::
 --no-log::
 	In addition to branch names, populate the log message with
-	one-line descriptions from the actual commits that are being
-	merged.
+	one-line descriptions from at most <n> actual commits that are being
+	merged. See also linkgit:git-fmt-merge-msg[1].
 +
 With --no-log do not list one-line descriptions from the
 actual commits being merged.

builtin.h

@@ -7,14 +7,15 @@
 #include "commit.h"
 #include "notes.h"
 
+#define DEFAULT_MERGE_LOG_LEN 20
+
 extern const char git_version_string[];
 extern const char git_usage_string[];
 extern const char git_more_info_string[];
 
 extern void prune_packed_objects(int);
-extern int fmt_merge_msg(int merge_summary, struct strbuf *in,
-	struct strbuf *out);
-extern int fmt_merge_msg_shortlog(struct strbuf *in, struct strbuf *out);
+extern int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
+			 int merge_title, int shortlog_len);
 extern int commit_notes(struct notes_tree *t, const char *msg);
 
 struct notes_rewrite_cfg {

builtin/fmt-merge-msg.c

@@ -7,21 +7,22 @@
 #include "string-list.h"
 
 static const char * const fmt_merge_msg_usage[] = {
-	"git fmt-merge-msg [-m <message>] [--log|--no-log] [--file <file>]",
+	"git fmt-merge-msg [-m <message>] [--log[=<n>]|--no-log] [--file <file>]",
 	NULL
 };
 
-static int merge_summary;
+static int shortlog_len;
 
 static int fmt_merge_msg_config(const char *key, const char *value, void *cb)
 {
-	static int found_merge_log = 0;
-	if (!strcmp("merge.log", key)) {
-		found_merge_log = 1;
-		merge_summary = git_config_bool(key, value);
+	if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
+		int is_bool;
+		shortlog_len = git_config_bool_or_int(key, value, &is_bool);
+		if (!is_bool && shortlog_len < 0)
+			return error("%s: negative length %s", key, value);
+		if (is_bool && shortlog_len)
+			shortlog_len = DEFAULT_MERGE_LOG_LEN;
 	}
-	if (!found_merge_log && !strcmp("merge.summary", key))
-		merge_summary = git_config_bool(key, value);
 	return 0;
 }
 
@@ -255,9 +256,9 @@ static void do_fmt_merge_msg_title(struct strbuf *out,
 		strbuf_addf(out, " into %s\n", current_branch);
 }
 
-static int do_fmt_merge_msg(int merge_title, int merge_summary,
-	struct strbuf *in, struct strbuf *out) {
-	int limit = 20, i = 0, pos = 0;
+static int do_fmt_merge_msg(int merge_title, struct strbuf *in,
+	struct strbuf *out, int shortlog_len) {
+	int i = 0, pos = 0;
 	unsigned char head_sha1[20];
 	const char *current_branch;
 
@@ -288,7 +289,7 @@ static int do_fmt_merge_msg(int merge_title, int merge_summary,
 	if (merge_title)
 		do_fmt_merge_msg_title(out, current_branch);
 
-	if (merge_summary) {
+	if (shortlog_len) {
 		struct commit *head;
 		struct rev_info rev;
 
@@ -303,28 +304,28 @@ static int do_fmt_merge_msg(int merge_title, int merge_summary,
 
 		for (i = 0; i < origins.nr; i++)
 			shortlog(origins.items[i].string, origins.items[i].util,
-					head, &rev, limit, out);
+					head, &rev, shortlog_len, out);
 	}
 	return 0;
 }
 
-int fmt_merge_msg(int merge_summary, struct strbuf *in, struct strbuf *out) {
-	return do_fmt_merge_msg(1, merge_summary, in, out);
-}
-
-int fmt_merge_msg_shortlog(struct strbuf *in, struct strbuf *out) {
-	return do_fmt_merge_msg(0, 1, in, out);
+int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
+		  int merge_title, int shortlog_len) {
+	return do_fmt_merge_msg(merge_title, in, out, shortlog_len);
 }
 
 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 {
 	const char *inpath = NULL;
 	const char *message = NULL;
 	struct option options[] = {
-		OPT_BOOLEAN(0, "log",     &merge_summary, "populate log with the shortlog"),
-		{ OPTION_BOOLEAN, 0, "summary", &merge_summary, NULL,
+		{ OPTION_INTEGER, 0, "log", &shortlog_len, "n",
+		  "populate log with at most <n> entries from shortlog",
+		  PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
+		{ OPTION_INTEGER, 0, "summary", &shortlog_len, "n",
 		  "alias for --log (deprecated)",
-		  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
+		  PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
+		  DEFAULT_MERGE_LOG_LEN },
 		OPT_STRING('m', "message", &message, "text",
 			"use <text> as start of message"),
 		OPT_FILENAME('F', "file", &inpath, "file to read from"),
@@ -340,12 +341,14 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 			     0);
 	if (argc > 0)
 		usage_with_options(fmt_merge_msg_usage, options);
-	if (message && !merge_summary) {
+	if (message && !shortlog_len) {
 		char nl = '\n';
 		write_in_full(STDOUT_FILENO, message, strlen(message));
 		write_in_full(STDOUT_FILENO, &nl, 1);
 		return 0;
 	}
+	if (shortlog_len < 0)
+		die("Negative --log=%d", shortlog_len);
 
 	if (inpath && strcmp(inpath, "-")) {
 		in = fopen(inpath, "r");
@@ -355,12 +358,13 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 
 	if (strbuf_read(&input, fileno(in), 0) < 0)
 		die_errno("could not read input file");
-	if (message) {
+
+	if (message)
 		strbuf_addstr(&output, message);
-		ret = fmt_merge_msg_shortlog(&input, &output);
-	} else {
-		ret = fmt_merge_msg(merge_summary, &input, &output);
-	}
+	ret = fmt_merge_msg(&input, &output,
+			    message ? 0 : 1,
+			    shortlog_len);
+
 	if (ret)
 		return ret;
 	write_in_full(STDOUT_FILENO, output.buf, output.len);

builtin/merge.c

@@ -42,7 +42,7 @@ static const char * const builtin_merge_usage[] = {
 	NULL
 };
 
-static int show_diffstat = 1, option_log, squash;
+static int show_diffstat = 1, shortlog_len, squash;
 static int option_commit = 1, allow_fast_forward = 1;
 static int fast_forward_only;
 static int allow_trivial = 1, have_message;
@@ -177,8 +177,9 @@ static struct option builtin_merge_options[] = {
 	OPT_BOOLEAN(0, "stat", &show_diffstat,
 		"show a diffstat at the end of the merge"),
 	OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
-	OPT_BOOLEAN(0, "log", &option_log,
-		"add list of one-line log to merge commit message"),
+	{ OPTION_INTEGER, 0, "log", &shortlog_len, "n",
+	  "add (at most <n>) entries from shortlog to merge commit message",
+	  PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
 	OPT_BOOLEAN(0, "squash", &squash,
 		"create a single commit instead of doing a merge"),
 	OPT_BOOLEAN(0, "commit", &option_commit,
@@ -504,10 +505,17 @@ 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, "merge.log") || !strcmp(k, "merge.summary"))
-		option_log = git_config_bool(k, v);
 	else if (!strcmp(k, "merge.renormalize"))
 		option_renormalize = git_config_bool(k, v);
+	else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary")) {
+		int is_bool;
+		shortlog_len = git_config_bool_or_int(k, v, &is_bool);
+		if (!is_bool && shortlog_len < 0)
+			return error("%s: negative length %s", k, v);
+		if (is_bool && shortlog_len)
+			shortlog_len = DEFAULT_MERGE_LOG_LEN;
+		return 0;
+	}
 	return git_diff_ui_config(k, v, cb);
 }
 
@@ -1012,14 +1020,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		for (i = 0; i < argc; i++)
 			merge_name(argv[i], &merge_names);
 
-		if (have_message && option_log)
-			fmt_merge_msg_shortlog(&merge_names, &merge_msg);
-		else if (!have_message)
-			fmt_merge_msg(option_log, &merge_names, &merge_msg);
-
-
-		if (!(have_message && !option_log) && merge_msg.len)
-			strbuf_setlen(&merge_msg, merge_msg.len-1);
+		if (!have_message || shortlog_len) {
+			fmt_merge_msg(&merge_names, &merge_msg, !have_message,
+				      shortlog_len);
+			if (merge_msg.len)
+				strbuf_setlen(&merge_msg, merge_msg.len - 1);
+		}
 	}
 
 	if (head_invalid || !argc)

t/t6200-fmt-merge-msg.sh

@@ -129,6 +129,97 @@ test_expect_success '[merge] summary/log configuration' '
 	test_cmp expected actual2
 '
 
+test_expect_success 'setup: clear [merge] configuration' '
+	test_might_fail git config --unset-all merge.log &&
+	test_might_fail git config --unset-all merge.summary
+'
+
+test_expect_success 'setup FETCH_HEAD' '
+	git checkout master &&
+	test_tick &&
+	git fetch . left
+'
+
+test_expect_success 'merge.log=3 limits shortlog length' '
+	cat >expected <<-EOF &&
+	Merge branch ${apos}left${apos}
+
+	* left: (5 commits)
+	  Left #5
+	  Left #4
+	  Left #3
+	  ...
+	EOF
+
+	git -c merge.log=3 fmt-merge-msg <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'merge.log=5 shows all 5 commits' '
+	cat >expected <<-EOF &&
+	Merge branch ${apos}left${apos}
+
+	* left:
+	  Left #5
+	  Left #4
+	  Left #3
+	  Common #2
+	  Common #1
+	EOF
+
+	git -c merge.log=5 fmt-merge-msg <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'merge.log=0 disables shortlog' '
+	echo "Merge branch ${apos}left${apos}" >expected
+	git -c merge.log=0 fmt-merge-msg <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success '--log=3 limits shortlog length' '
+	cat >expected <<-EOF &&
+	Merge branch ${apos}left${apos}
+
+	* left: (5 commits)
+	  Left #5
+	  Left #4
+	  Left #3
+	  ...
+	EOF
+
+	git fmt-merge-msg --log=3 <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success '--log=5 shows all 5 commits' '
+	cat >expected <<-EOF &&
+	Merge branch ${apos}left${apos}
+
+	* left:
+	  Left #5
+	  Left #4
+	  Left #3
+	  Common #2
+	  Common #1
+	EOF
+
+	git fmt-merge-msg --log=5 <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success '--no-log disables shortlog' '
+	echo "Merge branch ${apos}left${apos}" >expected &&
+	git fmt-merge-msg --no-log <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success '--log=0 disables shortlog' '
+	echo "Merge branch ${apos}left${apos}" >expected &&
+	git fmt-merge-msg --no-log <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'fmt-merge-msg -m' '
 	echo "Sync with left" >expected &&
 	cat >expected.log <<-EOF &&