Merge branch 'rt/help-unknown'

"git nosuchcommand --help" said "No manual entry for gitnosuchcommand",
which was not intuitive, given that "git nosuchcommand" said "git:
'nosuchcommand' is not a git command".

* rt/help-unknown:
  help: make option --help open man pages only for Git commands
  help: introduce option --exclude-guides

builtin/help.c

@@ -37,8 +37,10 @@ static int show_all = 0;
 static int show_guides = 0;
 static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
+static int exclude_guides;
 static struct option builtin_help_options[] = {
 	OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
+	OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
 	OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
 	OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
 	OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
@@ -426,10 +428,29 @@ static void list_common_guides_help(void)
 	putchar('\n');
 }
 
+static const char *check_git_cmd(const char* cmd)
+{
+	char *alias;
+
+	if (is_git_command(cmd))
+		return cmd;
+
+	alias = alias_lookup(cmd);
+	if (alias) {
+		printf_ln(_("`git %s' is aliased to `%s'"), cmd, alias);
+		free(alias);
+		exit(0);
+	}
+
+	if (exclude_guides)
+		return help_unknown_cmd(cmd);
+
+	return cmd;
+}
+
 int cmd_help(int argc, const char **argv, const char *prefix)
 {
 	int nongit;
-	char *alias;
 	enum help_format parsed_help_format;
 
 	argc = parse_options(argc, argv, prefix, builtin_help_options,
@@ -469,12 +490,7 @@ int cmd_help(int argc, const char **argv, const char *prefix)
 	if (help_format == HELP_FORMAT_NONE)
 		help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 
-	alias = alias_lookup(argv[0]);
-	if (alias && !is_git_command(argv[0])) {
-		printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
-		free(alias);
-		return 0;
-	}
+	argv[0] = check_git_cmd(argv[0]);
 
 	switch (help_format) {
 	case HELP_FORMAT_NONE:

git.c

@@ -522,21 +522,34 @@ static void strip_extension(const char **argv)
 
 static void handle_builtin(int argc, const char **argv)
 {
+	struct argv_array args = ARGV_ARRAY_INIT;
 	const char *cmd;
 	struct cmd_struct *builtin;
 
 	strip_extension(argv);
 	cmd = argv[0];
 
-	/* Turn "git cmd --help" into "git help cmd" */
+	/* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 	if (argc > 1 && !strcmp(argv[1], "--help")) {
+		int i;
+
 		argv[1] = argv[0];
 		argv[0] = cmd = "help";
+
+		for (i = 0; i < argc; i++) {
+			argv_array_push(&args, argv[i]);
+			if (!i)
+				argv_array_push(&args, "--exclude-guides");
+		}
+
+		argc++;
+		argv = args.argv;
 	}
 
 	builtin = get_builtin(cmd);
 	if (builtin)
 		exit(run_builtin(builtin, argc, argv));
+	argv_array_clear(&args);
 }
 
 static void execv_dashed_external(const char **argv)

t/t0012-help.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+test_description='help'
+
+. ./test-lib.sh
+
+configure_help () {
+	test_config help.format html &&
+
+	# Unless the path has "://" in it, Git tries to make sure
+	# the documentation directory locally exists. Avoid it as
+	# we are only interested in seeing an attempt to correctly
+	# invoke a help browser in this test.
+	test_config help.htmlpath test://html &&
+
+	# Name a custom browser
+	test_config browser.test.cmd ./test-browser &&
+	test_config help.browser test
+}
+
+test_expect_success "setup" '
+	# Just write out which page gets requested
+	write_script test-browser <<-\EOF
+	echo "$*" >test-browser.log
+	EOF
+'
+
+test_expect_success "works for commands and guides by default" '
+	configure_help &&
+	git help status &&
+	echo "test://html/git-status.html" >expect &&
+	test_cmp expect test-browser.log &&
+	git help revisions &&
+	echo "test://html/gitrevisions.html" >expect &&
+	test_cmp expect test-browser.log
+'
+
+test_expect_success "--exclude-guides does not work for guides" '
+	>test-browser.log &&
+	test_must_fail git help --exclude-guides revisions &&
+	test_must_be_empty test-browser.log
+'
+
+test_expect_success "--help does not work for guides" "
+	cat <<-EOF >expect &&
+		git: 'revisions' is not a git command. See 'git --help'.
+	EOF
+	test_must_fail git revisions --help 2>actual &&
+	test_i18ncmp expect actual
+"
+
+test_done