.gitmodules: add comments about relative URL. No change.

marc-hb · kv2019i · commit 3f24c05ab276 · 2023-05-08T12:19:17.000+03:00
Answering a question from @ceolin and others before him. Signed-off-by: Marc Herbert <marc.herbert@intel.com>
diff --git a/.gitmodules b/.gitmodules
@@ -1,3 +1,19 @@
 [submodule "rimage"]
 	path = rimage
+# This is a _relative_ submodule URL. In some use cases it's better than
+# an _absolute_ submodule URL, in other cases it's not. One size does
+# unfortunately not fit all.
+#
+# Among other pages, http://blog.tremily.us/posts/Relative_submodules/
+# has a good comparison
+#
+# If you use Zephyr you must also look at the comments in sof/west.yml.
+#
+# If you want to fork or mirror sof.git _without_ doing the same for
+# rimage.git then your automation may want you to change and git commit
+# an absolute URL in your branch. No need to git commit for interactive
+# use; a local and temporary edit of this file is enough for interactive
+# use because .gitmodules is used only once to --init[ialize]
+# .git/config the first time. Then .gitmodules is never used again after
+# cloning.
 	url = ../rimage
