No patches found error with simple git diff and no PR message body #360

I have the following git diff I tried to submit to my own repository:

diff --git a/lexicon/world.geocache.visit.json b/lexicon/world.geocache.visit.json
index 94c8ce0..1a072ce 100644
--- a/lexicon/world.geocache.visit.json
+++ b/lexicon/world.geocache.visit.json
@@ -42,7 +42,7 @@
       "type": "object",
       "required": ["record"],
       "properties": {
-        "record": { "type": "ref", "ref": "com.atproto.ref.strongRef" }
+        "record": { "type": "ref", "ref": "com.atproto.repo.strongRef" }
       }
     },
     "image": {

I initially tried creating the PR without a message body, and got the error No patches found in the supplied format-patch. This error went away after adding a message body and I was able to submit the PR successfully.

I'm looking at the relevant code, and I can't quite tell if this is intended behavior or not... a more clear error message would be appreciated in either case.