Commits may fail to be deserialized because sha field may be null in DiffEntry if contents did not change

[fiadliel]

When a commit includes file(s) that have no changes to the contents, the sha field is null. e.g. the file mode changed from 100644 to 10755.

When trying to parse the commit response, this error shows up:

Json { source: Error { path: Path { segments: [Map { key: "files" }, Seq { index: 0 }, Map { key: "sha" }] }, original: Error("invalid type: null, expected a string", line: 1, column: 4929) }

Looking at the code, this can only happen with the sha field of the DiffEntry struct. If I modify the code to make this field optional, the request works.

I note that this behavior actually differs from what GitHub claim here: https://docs.github.com/en/rest/commits/commits?apiVersion=2022-11-28#get-a-commit
It says that sha is a required field, but that doesn't appear to be the case in this one situation.