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From: Taylor Blau <me@ttaylorr.com>
To: git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>, Tribo Dar <3bodar@gmail.com>,
	Stefan Beller <stefanbeller@gmail.com>
Subject: [PATCH] builtin/submodule--helper.c: handle missing submodule URLs
Date: Wed, 24 May 2023 12:02:26 -0400	[thread overview]
Message-ID: <f7a8de14fe255286e62fc46d0a3083189f46bcc6.1684944140.git.me@ttaylorr.com> (raw)
In-Reply-To: <ZG4jcceXn2G6Xic0@nand.local>

In e0a862fdaf (submodule helper: convert relative URL to absolute URL if
needed, 2018-10-16), `prepare_to_clone_next_submodule()` lost the
ability to handle URL-less submodules, due to a change from:

    if (repo_get_config_string_const(the_repostiory, sb.buf, &url))
        url = sub->url;

to

    if (repo_get_config_string_const(the_repostiory, sb.buf, &url)) {
        if (starts_with_dot_slash(sub->url) ||
            starts_with_dot_dot_slash(sub->url)) {
                /* ... */
            }
    }

, which will segfault when `sub->url` is NULL, since both
`starts_with_dot_slash()` does not guard its arguments as non-NULL.

Guard the checks to both of the above functions by first whether
`sub->url` is non-NULL. There is no need to check whether `sub` itself
is NULL, since we already perform this check earlier in
`prepare_to_clone_next_submodule()`.

By adding a NULL-ness check on `sub->url`, we'll fall into the 'else'
branch, setting `url` to `sub->url` (which is NULL). When we then try
and invoke `git submodule-helper` below, we'll get the expected error
message:

    error: option `url' requires a value

Note that this means that `--url` and its value must come last when
preparing the argument list, to avoid confusing the next argument as the
value for `--url` if `url` itself is NULL.

Reported-by: Tribo Dar <3bodar@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 builtin/submodule--helper.c | 11 ++++++++---
 t/t7400-submodule-basic.sh  | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 6bf8d666ce..a7b7ea374f 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2024,8 +2024,8 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (repo_config_get_string_tmp(the_repository, sb.buf, &url)) {
-		if (starts_with_dot_slash(sub->url) ||
-		    starts_with_dot_dot_slash(sub->url)) {
+		if (sub->url && (starts_with_dot_slash(sub->url) ||
+				 starts_with_dot_dot_slash(sub->url))) {
 			url = resolve_relative_url(sub->url, NULL, 0);
 			need_free_url = 1;
 		} else
@@ -2069,7 +2069,6 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		strvec_push(&child->args, "--require-init");
 	strvec_pushl(&child->args, "--path", sub->path, NULL);
 	strvec_pushl(&child->args, "--name", sub->name, NULL);
-	strvec_pushl(&child->args, "--url", url, NULL);
 	if (suc->update_data->references.nr) {
 		struct string_list_item *item;
 
@@ -2082,6 +2081,12 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		strvec_push(&child->args, suc->update_data->single_branch ?
 					      "--single-branch" :
 					      "--no-single-branch");
+	/*
+	 * `url` might be NULL, so ensure that this argument is passed
+	 * last to avoid confusing the next argument as the value for
+	 * `--url`.
+	 */
+	strvec_pushl(&child->args, "--url", url, NULL);
 
 cleanup:
 	free(displaypath);
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index eae6a46ef3..c97c543dd8 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -1351,6 +1351,22 @@ test_expect_success 'clone active submodule without submodule url set' '
 	)
 '
 
+test_expect_success 'update submodules without url set in .gitconfig' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+
+	git -C multisuper_clone submodule init &&
+	for s in sub0 sub1 sub2 sub3
+	do
+		key=submodule.$s.url &&
+		git -C multisuper_clone config --local --unset $key &&
+		git -C multisuper_clone config --file .gitmodules --unset $key || return 1
+	done &&
+
+	test_must_fail git -C multisuper_clone submodule update 2>err &&
+	grep "option .url. requires a value" err
+'
+
 test_expect_success 'clone --recurse-submodules with a pathspec works' '
 	test_when_finished "rm -rf multisuper_clone" &&
 	cat >expected <<-\EOF &&
-- 
2.41.0.rc1.11.gf7a8de14fe

  reply	other threads:[~2023-05-24 16:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-24  6:59 [BUG] Segmentation fault in git v2.41.0.rc1 Tribo Dar
2023-05-24 14:47 ` Taylor Blau
2023-05-24 16:02   ` Taylor Blau [this message]
2023-05-24 16:25     ` [PATCH v2] builtin/submodule--helper.c: handle missing submodule URLs Taylor Blau
2023-05-24 18:48       ` Eric Sunshine
2023-05-24 19:50         ` Taylor Blau
2023-05-24 19:51     ` [PATCH v3] " Taylor Blau
2023-05-24 20:29       ` René Scharfe
2023-05-24 20:36         ` Taylor Blau
2023-05-24 20:33       ` Jeff King
2023-05-24 22:58     ` [PATCH] " Jeff King
2023-05-24 20:25   ` [BUG] Segmentation fault in git v2.41.0.rc1 Junio C Hamano

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