submodule-config: clarify parsing of null_sha1 element

stefanbeller · gitster · commit f2627d9b19f9 · 2016-11-22T14:43:04.000-08:00
Signed-off-by: Stefan Beller &lt;sbeller@google.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
Reviewed-by: Brandon Williams &lt;bmwill@google.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt
@@ -56,8 +56,11 @@ Functions
 
 	The same as above but lookup by name.
 
-If given the null_sha1 as treeish_name the local configuration of a
-submodule will be returned (e.g. consolidated values from local git
+Whenever a submodule configuration is parsed in `parse_submodule_config_option`
+via e.g. `gitmodules_config()`, it will overwrite the null_sha1 entry.
+So in the normal case, when HEAD:.gitmodules is parsed first and then overlayed
+with the repository configuration, the null_sha1 entry contains the local
+configuration of a submodule (e.g. consolidated values from local git
 configuration and the .gitmodules file in the worktree).
 
 For an example usage see test-submodule-config.c.
