for-each-repo: do nothing on empty config

'git for-each-repo --config=X' should return success without calling any
subcommands when the config key 'X' has no value. The current
implementation instead segfaults.

A user could run into this issue if they used 'git maintenance start' to
initialize their cron schedule using 'git for-each-repo
--config=maintenance.repo ...' but then using 'git maintenance
unregister' to remove the config option. (Note: 'git maintenance stop'
would remove the config _and_ remove the cron schedule.)

Add a simple test to ensure this works. Use 'git help --no-such-option'
as the potential subcommand to ensure that we will hit a failure if the
subcommand is ever run.

Reported-by: Andreas Bühmann <dev@uuml.de>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/for-each-repo.c b/builtin/for-each-repo.c
index 5bba623ff12787c31912191835141cee0068d87c..52be64a4373a3a4fb992662aaee54e17c9d03b46 100644 (file)
--- a/builtin/for-each-repo.c
+++ b/builtin/for-each-repo.c
@@ -51,6 +51,13 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
        values = repo_config_get_value_multi(the_repository,
                                             config_key);
 
+       /*
+        * Do nothing on an empty list, which is equivalent to the case
+        * where the config variable does not exist at all.
+        */
+       if (!values)
+               return 0;
+
        for (i = 0; !result && i < values->nr; i++)
                result = run_command_on_repo(values->items[i].string, &args);
 

diff --git a/t/t0068-for-each-repo.sh b/t/t0068-for-each-repo.sh
index 136b4ec8392817eec21153b37f94ab3167f5f106..4675e852517688179c2783803ebfa56e730cd24c 100755 (executable)
--- a/t/t0068-for-each-repo.sh
+++ b/t/t0068-for-each-repo.sh
@@ -27,4 +27,10 @@ test_expect_success 'run based on configured value' '
        grep again message
 '
 
+test_expect_success 'do nothing on empty config' '
+       # the whole thing would fail if for-each-ref iterated even
+       # once, because "git help --no-such-option" would fail
+       git for-each-repo --config=bogus.config -- help --no-such-option
+'
+
 test_done