[PATCH 3/4] clone: validate --origin option before use

["Sean Barag via GitGitGadget" <gitgitgadget@gmail.com>]

From: Sean Barag <sean@barag.org>

Providing a bad origin name to `git clone` currently reports an
'invalid refspec' error instead of a more explicit message explaining
that the `--origin` option was malformed.  Per Junio, it's been this way
since 8434c2f1 (Build in clone, 2008-04-27).  This patch reintroduces
validation for the provided `--origin` option, but notably _doesn't_
include a multi-level check (e.g. "foo/bar") that was present in the
original `git-clone.sh`.  It seems `git remote` allows multi-level
remote names, so applying that same validation in `git clone` seems
reasonable.

Signed-off-by: Sean Barag <sean@barag.org>
Thanks-to: Junio C Hamano <gitster@pobox.com>
---
 builtin/clone.c          | 7 +++++++
 t/t5606-clone-options.sh | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/builtin/clone.c b/builtin/clone.c
index bf095815f0..1cd62d0001 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -967,6 +967,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	const struct ref *ref;
 	struct strbuf key = STRBUF_INIT;
 	struct strbuf default_refspec = STRBUF_INIT;
+	struct strbuf resolved_refspec = STRBUF_INIT;
 	struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
 	struct transport *transport = NULL;
 	const char *src_ref_prefix = "refs/heads/";
@@ -1011,6 +1012,12 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (!option_origin)
 		option_origin = "origin";
 
+	strbuf_addf(&resolved_refspec, "refs/heads/test:refs/remotes/%s/test", option_origin);
+	if (!valid_fetch_refspec(resolved_refspec.buf))
+		/* TRANSLATORS: %s will be the user-provided --origin / -o option */
+		die(_("'%s' is not a valid origin name"), option_origin);
+	strbuf_release(&resolved_refspec);
+
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);
diff --git a/t/t5606-clone-options.sh b/t/t5606-clone-options.sh
index d20a78f84b..c865f96def 100755
--- a/t/t5606-clone-options.sh
+++ b/t/t5606-clone-options.sh
@@ -19,6 +19,14 @@ test_expect_success 'clone -o' '
 
 '
 
+test_expect_success 'rejects invalid -o/--origin' '
+
+	test_expect_code 128 git clone -o "bad...name" parent clone-bad-name 2>err &&
+	test_debug "cat err" &&
+	test_i18ngrep "'\''bad...name'\'' is not a valid origin name" err
+
+'
+
 test_expect_success 'disallows --bare with --origin' '
 
 	test_expect_code 128 git clone -o foo --bare parent clone-bare-o 2>err &&
-- 
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