builtin: also setup gently for --help-all

Git experts often check the help summary of a command to make sure they
spell options right when suggesting advice to colleagues. Further, they
might check hidden options when responding to queries about deprecated
options like git-rebase(1)'s "preserve merges" option. But some commands
don't support "--help-all" outside of a git directory. Running (for
example)

    git rebase --help-all

outside a directory fails in "setup_git_directory", erroring with the
localized form of

    fatal: not a git repository (or any of the parent directories): .git

Like 99caeed05d (Let 'git <command> -h' show usage without a git dir,
2009-11-09), we want to show the "--help-all" output even without a git
dir. Make "--help-all" where we expect "-h" to mean
"setup_git_directory_gently", and interpose early in the natural place
("show_usage_with_options_if_asked").

Do the same for usage callers with show_usage_if_asked.

The exception is merge-recursive, whose help block doesn't use newer
APIs.

Best-viewed-with: --ignore-space-change
Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/builtin/merge-recursive.c b/builtin/merge-recursive.c
index 03b5100cfa..17aa4db37a 100644
--- a/builtin/merge-recursive.c
+++ b/builtin/merge-recursive.c
@@ -38,7 +38,8 @@ int cmd_merge_recursive(int argc,
 	if (argv[0] && ends_with(argv[0], "-subtree"))
 		o.subtree_shift = "";
 
-	if (argc == 2 && !strcmp(argv[1], "-h")) {
+	if (argc == 2 && (!strcmp(argv[1], "-h") ||
+			  !strcmp(argv[1], "--help-all"))) {
 		struct strbuf msg = STRBUF_INIT;
 		strbuf_addf(&msg, builtin_merge_recursive_usage, argv[0]);
 		show_usage_if_asked(argc, argv, msg.buf);