rebase: rename the two primary rebase backends

Two related changes, with separate rationale for each:

Rename the 'interactive' backend to 'merge' because:
  * 'interactive' as a name caused confusion; this backend has been used
    for many kinds of non-interactive rebases, and will probably be used
    in the future for more non-interactive rebases than interactive ones
    given that we are making it the default.
  * 'interactive' is not the underlying strategy; merging is.
  * the directory where state is stored is not called
    .git/rebase-interactive but .git/rebase-merge.

Rename the 'am' backend to 'apply' because:
  * Few users are familiar with git-am as a reference point.
  * Related to the above, the name 'am' makes sentences in the
    documentation harder for users to read and comprehend (they may read
    it as the verb from "I am"); avoiding this difficult places a large
    burden on anyone writing documentation about this backend to be very
    careful with quoting and sentence structure and often forces
    annoying redundancy to try to avoid such problems.
  * Users stumble over pronunciation ("am" as in "I am a person not a
    backend" or "am" as in "the first and thirteenth letters in the
    alphabet in order are "A-M"); this may drive confusion when one user
    tries to explain to another what they are doing.
  * While "am" is the tool driving this backend, the tool driving git-am
    is git-apply, and since we are driving towards lower-level tools
    for the naming of the merge backend we may as well do so here too.
  * The directory where state is stored has never been called
    .git/rebase-am, it was always called .git/rebase-apply.

For all the reasons listed above:
  * Modify the documentation to refer to the backends with the new names
  * Provide a brief note in the documentation connecting the new names
    to the old names in case users run across the old names anywhere
    (e.g. in old release notes or older versions of the documentation)
  * Change the (new) --am command line flag to --apply
  * Rename some enums, variables, and functions to reinforce the new
    backend names for us as well.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 47 insertions, 52 deletions

diff --git a/builtin/rebase.c b/builtin/rebase.c
index db8fd69..f3036f4 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -44,9 +44,8 @@ static GIT_PATH_FUNC(merge_dir, "rebase-merge")
 
 enum rebase_type {
 	REBASE_UNSPECIFIED = -1,
-	REBASE_AM,
+	REBASE_APPLY,
 	REBASE_MERGE,
-	REBASE_INTERACTIVE,
 	REBASE_PRESERVE_MERGES
 };
 
@@ -380,7 +379,7 @@ static int do_interactive_rebase(struct rebase_options *opts, unsigned flags)
 	return ret;
 }
 
-static int run_rebase_interactive(struct rebase_options *opts,
+static int run_sequencer_rebase(struct rebase_options *opts,
 				  enum action command)
 {
 	unsigned flags = 0;
@@ -462,7 +461,7 @@ static int parse_opt_keep_empty(const struct option *opt, const char *arg,
 	 * If we ever want to remap --keep-empty to --empty=keep, insert:
 	 * 	opts->empty = unset ? EMPTY_UNSPECIFIED : EMPTY_KEEP;
 	 */
-	opts->type = REBASE_INTERACTIVE;
+	opts->type = REBASE_MERGE;
 	return 0;
 }
 
@@ -555,28 +554,26 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 		warning(_("--[no-]rebase-cousins has no effect without "
 			  "--rebase-merges"));
 
-	return !!run_rebase_interactive(&opts, command);
+	return !!run_sequencer_rebase(&opts, command);
 }
 
-static int is_interactive(struct rebase_options *opts)
+static int is_merge(struct rebase_options *opts)
 {
-	return opts->type == REBASE_INTERACTIVE ||
+	return opts->type == REBASE_MERGE ||
 		opts->type == REBASE_PRESERVE_MERGES;
 }
 
-static void imply_interactive(struct rebase_options *opts, const char *option)
+static void imply_merge(struct rebase_options *opts, const char *option)
 {
 	switch (opts->type) {
-	case REBASE_AM:
+	case REBASE_APPLY:
 		die(_("%s requires an interactive rebase"), option);
 		break;
-	case REBASE_INTERACTIVE:
+	case REBASE_MERGE:
 	case REBASE_PRESERVE_MERGES:
 		break;
-	case REBASE_MERGE:
-		/* we now implement --merge via --interactive */
 	default:
-		opts->type = REBASE_INTERACTIVE; /* implied */
+		opts->type = REBASE_MERGE; /* implied */
 		break;
 	}
 }
@@ -785,7 +782,7 @@ static int finish_rebase(struct rebase_options *opts)
 	 * user should see them.
 	 */
 	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
-	if (opts->type == REBASE_INTERACTIVE) {
+	if (opts->type == REBASE_MERGE) {
 		struct replay_opts replay = REPLAY_OPTS_INIT;
 
 		replay.action = REPLAY_INTERACTIVE_REBASE;
@@ -1118,8 +1115,8 @@ static int run_specific_rebase(struct rebase_options *opts, enum action action)
 	int status;
 	const char *backend, *backend_func;
 
-	if (opts->type == REBASE_INTERACTIVE) {
-		/* Run builtin interactive rebase */
+	if (opts->type == REBASE_MERGE) {
+		/* Run sequencer-based rebase */
 		setenv("GIT_CHERRY_PICK_HELP", resolvemsg, 1);
 		if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 			setenv("GIT_SEQUENCE_EDITOR", ":", 1);
@@ -1132,11 +1129,11 @@ static int run_specific_rebase(struct rebase_options *opts, enum action action)
 			opts->gpg_sign_opt = tmp;
 		}
 
-		status = run_rebase_interactive(opts, action);
+		status = run_sequencer_rebase(opts, action);
 		goto finished_rebase;
 	}
 
-	if (opts->type == REBASE_AM) {
+	if (opts->type == REBASE_APPLY) {
 		status = run_am(opts);
 		goto finished_rebase;
 	}
@@ -1190,7 +1187,7 @@ static int run_specific_rebase(struct rebase_options *opts, enum action action)
 	add_var(&script_snippet, "git_format_patch_opt",
 		opts->git_format_patch_opt.buf);
 
-	if (is_interactive(opts) &&
+	if (is_merge(opts) &&
 	    !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 		strbuf_addstr(&script_snippet,
 			      "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
@@ -1215,8 +1212,8 @@ static int run_specific_rebase(struct rebase_options *opts, enum action action)
 finished_rebase:
 	if (opts->dont_finish_rebase)
 		; /* do nothing */
-	else if (opts->type == REBASE_INTERACTIVE)
-		; /* interactive rebase cleans up after itself */
+	else if (opts->type == REBASE_MERGE)
+		; /* merge backend cleans up after itself */
 	else if (status == 0) {
 		if (!file_exists(state_dir_path("stopped-sha", opts)))
 			finish_rebase(opts);
@@ -1348,7 +1345,7 @@ static int parse_opt_am(const struct option *opt, const char *arg, int unset)
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
 
-	opts->type = REBASE_AM;
+	opts->type = REBASE_APPLY;
 
 	return 0;
 }
@@ -1361,7 +1358,7 @@ static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
 
-	if (!is_interactive(opts))
+	if (!is_merge(opts))
 		opts->type = REBASE_MERGE;
 
 	return 0;
@@ -1376,7 +1373,7 @@ static int parse_opt_interactive(const struct option *opt, const char *arg,
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
 
-	opts->type = REBASE_INTERACTIVE;
+	opts->type = REBASE_MERGE;
 	opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 
 	return 0;
@@ -1440,7 +1437,7 @@ static void set_reflog_action(struct rebase_options *options)
 	const char *env;
 	struct strbuf buf = STRBUF_INIT;
 
-	if (!is_interactive(options))
+	if (!is_merge(options))
 		return;
 
 	env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
@@ -1537,8 +1534,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "show-current-patch", &action,
 			    N_("show the patch file being applied or merged"),
 			    ACTION_SHOW_CURRENT_PATCH),
-		{ OPTION_CALLBACK, 0, "am", &options, NULL,
-			N_("use apply-mail strategies to rebase"),
+		{ OPTION_CALLBACK, 0, "apply", &options, NULL,
+			N_("use apply strategies to rebase"),
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 			parse_opt_am },
 		{ OPTION_CALLBACK, 'm', "merge", &options, NULL,
@@ -1615,7 +1612,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		die(_("It looks like 'git am' is in progress. Cannot rebase."));
 
 	if (is_directory(apply_dir())) {
-		options.type = REBASE_AM;
+		options.type = REBASE_APPLY;
 		options.state_dir = apply_dir();
 	} else if (is_directory(merge_dir())) {
 		strbuf_reset(&buf);
@@ -1627,7 +1624,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			strbuf_reset(&buf);
 			strbuf_addf(&buf, "%s/interactive", merge_dir());
 			if(file_exists(buf.buf)) {
-				options.type = REBASE_INTERACTIVE;
+				options.type = REBASE_MERGE;
 				options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 			} else
 				options.type = REBASE_MERGE;
@@ -1667,12 +1664,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		die(_("No rebase in progress?"));
 	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
 
-	if (action == ACTION_EDIT_TODO && !is_interactive(&options))
+	if (action == ACTION_EDIT_TODO && !is_merge(&options))
 		die(_("The --edit-todo action can only be used during "
 		      "interactive rebase."));
 
 	if (trace2_is_enabled()) {
-		if (is_interactive(&options))
+		if (is_merge(&options))
 			trace2_cmd_mode("interactive");
 		else if (exec.nr)
 			trace2_cmd_mode("interactive-exec");
@@ -1748,7 +1745,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		goto cleanup;
 	}
 	case ACTION_QUIT: {
-		if (options.type == REBASE_INTERACTIVE) {
+		if (options.type == REBASE_MERGE) {
 			struct replay_opts replay = REPLAY_OPTS_INIT;
 
 			replay.action = REPLAY_INTERACTIVE_REBASE;
@@ -1831,7 +1828,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		argv_array_push(&options.git_am_opts, "-q");
 
 	if (options.empty != EMPTY_UNSPECIFIED)
-		imply_interactive(&options, "--empty");
+		imply_merge(&options, "--empty");
 
 	if (gpg_sign) {
 		free(options.gpg_sign_opt);
@@ -1841,7 +1838,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	if (exec.nr) {
 		int i;
 
-		imply_interactive(&options, "--exec");
+		imply_merge(&options, "--exec");
 
 		strbuf_reset(&buf);
 		for (i = 0; i < exec.nr; i++)
@@ -1857,7 +1854,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		else if (strcmp("no-rebase-cousins", rebase_merges))
 			die(_("Unknown mode: %s"), rebase_merges);
 		options.rebase_merges = 1;
-		imply_interactive(&options, "--rebase-merges");
+		imply_merge(&options, "--rebase-merges");
 	}
 
 	if (strategy_options.nr) {
@@ -1876,10 +1873,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	if (options.strategy) {
 		options.strategy = xstrdup(options.strategy);
 		switch (options.type) {
-		case REBASE_AM:
+		case REBASE_APPLY:
 			die(_("--strategy requires --merge or --interactive"));
 		case REBASE_MERGE:
-		case REBASE_INTERACTIVE:
 		case REBASE_PRESERVE_MERGES:
 			/* compatible */
 			break;
@@ -1892,34 +1888,34 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	}
 
 	if (options.type == REBASE_MERGE)
-		imply_interactive(&options, "--merge");
+		imply_merge(&options, "--merge");
 
 	if (options.root && !options.onto_name)
-		imply_interactive(&options, "--root without --onto");
+		imply_merge(&options, "--root without --onto");
 
 	if (isatty(2) && options.flags & REBASE_NO_QUIET)
 		strbuf_addstr(&options.git_format_patch_opt, " --progress");
 
-	if (options.git_am_opts.argc || options.type == REBASE_AM) {
-		/* all am options except -q are compatible only with --am */
+	if (options.git_am_opts.argc || options.type == REBASE_APPLY) {
+		/* all am options except -q are compatible only with --apply */
 		for (i = options.git_am_opts.argc - 1; i >= 0; i--)
 			if (strcmp(options.git_am_opts.argv[i], "-q"))
 				break;
 
 		if (i >= 0) {
-			if (is_interactive(&options))
-				die(_("cannot combine am options with either "
-				      "interactive or merge options"));
+			if (is_merge(&options))
+				die(_("cannot combine apply options with "
+				      "merge options"));
 			else
-				options.type = REBASE_AM;
+				options.type = REBASE_APPLY;
 		}
 	}
 
 	if (options.type == REBASE_UNSPECIFIED) {
 		if (!strcmp(options.default_backend, "merge"))
-			imply_interactive(&options, "--merge");
-		else if (!strcmp(options.default_backend, "am"))
-			options.type = REBASE_AM;
+			imply_merge(&options, "--merge");
+		else if (!strcmp(options.default_backend, "apply"))
+			options.type = REBASE_APPLY;
 		else
 			die(_("Unknown rebase backend: %s"),
 			    options.default_backend);
@@ -1927,11 +1923,10 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 	switch (options.type) {
 	case REBASE_MERGE:
-	case REBASE_INTERACTIVE:
 	case REBASE_PRESERVE_MERGES:
 		options.state_dir = merge_dir();
 		break;
-	case REBASE_AM:
+	case REBASE_APPLY:
 		options.state_dir = apply_dir();
 		break;
 	default:
@@ -1946,7 +1941,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		else
 			options.empty = EMPTY_DROP;
 	}
-	if (reschedule_failed_exec > 0 && !is_interactive(&options))
+	if (reschedule_failed_exec > 0 && !is_merge(&options))
 		die(_("--reschedule-failed-exec requires "
 		      "--exec or --interactive"));
 	if (reschedule_failed_exec >= 0)
@@ -2247,7 +2242,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		diff_flush(&opts);
 	}
 
-	if (is_interactive(&options))
+	if (is_merge(&options))
 		goto run_rebase;
 
 	/* Detach HEAD and reset the tree */