[PATCH 2/2] help: make option --help open man pages only for Git commands

[Ralf Thielow <ralf.thielow@gmail.com>]

If option --help is passed to a Git command, we try to open
the man page of that command.  However, we do it even for commands
we don't know.  Make sure it is a Git command.

This breaks "git <concept> --help" while "git help <concept>" still works.

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
---
 git.c           | 15 ++++++++++++++-
 t/t0012-help.sh |  8 ++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/git.c b/git.c
index 0f1937f..2cd2e06 100644
--- a/git.c
+++ b/git.c
@@ -528,10 +528,23 @@ static void handle_builtin(int argc, const char **argv)
 	strip_extension(argv);
 	cmd = argv[0];
 
-	/* Turn "git cmd --help" into "git help cmd" */
+	/* Turn "git cmd --help" into "git help --command-only cmd" */
 	if (argc > 1 && !strcmp(argv[1], "--help")) {
+		struct argv_array args;
+		int i;
+
 		argv[1] = argv[0];
 		argv[0] = cmd = "help";
+
+		argv_array_init(&args);
+		for (i = 0; i < argc; i++) {
+			argv_array_push(&args, argv[i]);
+			if (!i)
+				argv_array_push(&args, "--command-only");
+		}
+
+		argc++;
+		argv = argv_array_detach(&args);
 	}
 
 	builtin = get_builtin(cmd);
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index e20f907..81fec90 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -18,4 +18,12 @@ test_expect_success "--command-only does not work for guides" "
 	test_i18ncmp expected actual
 "
 
+test_expect_success "--help does not work for guides" "
+	cat <<-EOF >expected &&
+		git: 'revisions' is not a git command. See 'git --help'.
+	EOF
+	(git revisions --help 2>actual || true) &&
+	test_i18ncmp expected actual
+"
+
 test_done
-- 
2.9.2.912.gd0c0e83