setup: opt-out of check with safe.directory=*

With the addition of the safe.directory in 8959555ce
(setup_git_directory(): add an owner check for the top-level directory,
2022-03-02) released in v2.35.2, we are receiving feedback from a
variety of users about the feature.

Some users have a very large list of shared repositories and find it
cumbersome to add this config for every one of them.

In a more difficult case, certain workflows involve running Git commands
within containers. The container boundary prevents any global or system
config from communicating `safe.directory` values from the host into the
container. Further, the container almost always runs as a different user
than the owner of the directory in the host.

To simplify the reactions necessary for these users, extend the
definition of the safe.directory config value to include a possible '*'
value. This value implies that all directories are safe, providing a
single setting to opt-out of this protection.

Note that an empty assignment of safe.directory clears all previous
values, and this is already the case with the "if (!value || !*value)"
condition.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/setup.c b/setup.c
index 4b9f073617..aad9ace0af 100644
--- a/setup.c
+++ b/setup.c
@@ -1037,9 +1037,11 @@ static int safe_directory_cb(const char *key, const char *value, void *d)
 	if (strcmp(key, "safe.directory"))
 		return 0;
 
-	if (!value || !*value)
+	if (!value || !*value) {
 		data->is_safe = 0;
-	else {
+	} else if (!strcmp(value, "*")) {
+		data->is_safe = 1;
+	} else {
 		const char *interpolated = NULL;
 
 		if (!git_config_pathname(&interpolated, key, value) &&