submodule: trace adding submodule ODB as alternate

jonathantanmy · gitster · commit 71ef66d7403c · 2021-10-08T15:06:06.000-07:00
Submodule ODBs are never added as alternates during the execution of the
test suite, but there may be a rare interaction that the test suite does
not have coverage of. Add a trace message when this happens, so that
users who trace their commands can notice such occurrences.

Signed-off-by: Jonathan Tan &lt;jonathantanmy@google.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/submodule.c b/submodule.c
@@ -201,6 +201,8 @@ int register_all_submodule_odb_as_alternates(void)
 		add_to_alternates_memory(added_submodule_odb_paths.items[i].string);
 	if (ret) {
 		string_list_clear(&added_submodule_odb_paths, 0);
+		trace2_data_intmax("submodule", the_repository,
+				   "register_all_submodule_odb_as_alternates/registered", ret);
 		if (git_env_bool("GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB", 0))
 			BUG("register_all_submodule_odb_as_alternates() called");
 	}
diff --git a/t/README b/t/README
@@ -456,11 +456,8 @@ GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=<boolean>, when true, makes
 registering submodule ODBs as alternates a fatal action. Support for
 this environment variable can be removed once the migration to
 explicitly providing repositories when accessing submodule objects is
-complete (in which case we might want to replace this with a trace2
-call so that users can make it visible if accessing submodule objects
-without an explicit repository still happens) or needs to be abandoned
-for whatever reason (in which case the migrated codepaths still retain
-their performance benefits).
+complete or needs to be abandoned for whatever reason (in which case the
+migrated codepaths still retain their performance benefits).
 
 Naming Tests
 ------------

Original file line number	Diff line number	Diff line change
`@@ -201,6 +201,8 @@ int register_all_submodule_odb_as_alternates(void)`
`201`	`201`	`add_to_alternates_memory(added_submodule_odb_paths.items[i].string);`
`202`	`202`	`if (ret) {`
`203`	`203`	`string_list_clear(&added_submodule_odb_paths, 0);`
	`204`	`+ trace2_data_intmax("submodule", the_repository,`
	`205`	`+ "register_all_submodule_odb_as_alternates/registered", ret);`
`204`	`206`	`if (git_env_bool("GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB", 0))`
`205`	`207`	`BUG("register_all_submodule_odb_as_alternates() called");`
`206`	`208`	`}`