rebase -i: learn to abbreviate command names

`git rebase -i` already know how to interpret single-letter command
names. Teach it to generate the todo list with these same abbreviated
names.

Based-on-patch-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/rebase-config.txt

@@ -30,3 +30,23 @@ rebase.instructionFormat::
 	A format string, as specified in linkgit:git-log[1], to be used for the
 	todo list during an interactive rebase.  The format will
 	automatically have the long commit hash prepended to the format.
+
+rebase.abbreviateCommands::
+	If set to true, `git rebase` will use abbreviated command names in the
+	todo list resulting in something like this:
++
+-------------------------------------------
+	p deadbee The oneline of the commit
+	p fa1afe1 The oneline of the next commit
+	...
+-------------------------------------------
++
+instead of:
++
+-------------------------------------------
+	pick deadbee The oneline of the commit
+	pick fa1afe1 The oneline of the next commit
+	...
+-------------------------------------------
++
+Defaults to false.

builtin/rebase--helper.c

@@ -13,6 +13,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts = REPLAY_OPTS_INIT;
 	unsigned flags = 0, keep_empty = 0;
+	int abbreviate_commands = 0;
 	enum {
 		CONTINUE = 1, ABORT, MAKE_SCRIPT, SHORTEN_OIDS, EXPAND_OIDS,
 		CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH,
@@ -43,6 +44,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 	};
 
 	git_config(git_default_config, NULL);
+	git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
 
 	opts.action = REPLAY_INTERACTIVE_REBASE;
 	opts.allow_ff = 1;
@@ -52,6 +54,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 			builtin_rebase_helper_usage, PARSE_OPT_KEEP_ARGV0);
 
 	flags |= keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
+	flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
 	flags |= command == SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
 
 	if (command == CONTINUE && argc == 1)

sequencer.c

@@ -795,6 +795,13 @@ static const char *command_to_string(const enum todo_command command)
 	die("Unknown command: %d", command);
 }
 
+static const char command_to_char(const enum todo_command command)
+{
+	if (command < TODO_COMMENT && todo_command_info[command].c)
+		return todo_command_info[command].c;
+	return comment_line_char;
+}
+
 static int is_noop(const enum todo_command command)
 {
 	return TODO_NOOP <= command;
@@ -2453,6 +2460,7 @@ int sequencer_make_script(FILE *out, int argc, const char **argv,
 	struct rev_info revs;
 	struct commit *commit;
 	int keep_empty = flags & TODO_LIST_KEEP_EMPTY;
+	const char *insn = flags & TODO_LIST_ABBREVIATE_CMDS ? "p" : "pick";
 
 	init_revisions(&revs, NULL);
 	revs.verbose_header = 1;
@@ -2485,7 +2493,8 @@ int sequencer_make_script(FILE *out, int argc, const char **argv,
 		strbuf_reset(&buf);
 		if (!keep_empty && is_original_commit_empty(commit))
 			strbuf_addf(&buf, "%c ", comment_line_char);
-		strbuf_addf(&buf, "pick %s ", oid_to_hex(&commit->object.oid));
+		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);
@@ -2558,7 +2567,10 @@ int transform_todos(unsigned flags)
 		}
 
 		/* add command to the buffer */
-		strbuf_addstr(&buf, command_to_string(item->command));
+		if (flags & TODO_LIST_ABBREVIATE_CMDS)
+			strbuf_addch(&buf, command_to_char(item->command));
+		else
+			strbuf_addstr(&buf, command_to_string(item->command));
 
 		/* add commit id */
 		if (item->commit) {

sequencer.h

@@ -47,6 +47,7 @@ int sequencer_remove_state(struct replay_opts *opts);
 
 #define TODO_LIST_KEEP_EMPTY (1U << 0)
 #define TODO_LIST_SHORTEN_IDS (1U << 1)
+#define TODO_LIST_ABBREVIATE_CMDS (1U << 2)
 int sequencer_make_script(FILE *out, int argc, const char **argv,
 			  unsigned flags);