Junio C Hamano [off-list ref] writes:

Don't we want to pass down not just
--submodule-error=warn but --submodule-error=fail if that is what
was given from the command line?  Or does it not matter because fail
is the default?

Good catch, it does matter: the per-remote children of "fetch --all"
re-read the repository configuration, so a configured warn silently
won over an explicit --submodule-errors=fail.

Fixed in v4 by forwarding the resolved value whenever it was set
explicitly, in either direction; when nothing is set, nothing is
forwarded.  Added a test.

Thanks.