tree 420723f6cd7b09679b12248a13cb314b61f0d209
parent 5a91d6fe5e3fbe667eed9b27ed4d8293efb0cf56
author Éamonn McManus <emcmanus@google.com> 1715291586 -0700
committer Copybara-Service <copybara-worker@google.com> 1715291873 -0700

In `upb_MiniTableExtension_GetSubMessage`, return NULL for non-messages.

This parallels the logic in `upb_MiniTable_SubMessage`.

PiperOrigin-RevId: 632277936