commit 76b1389531e20b7e892cd4a3179252cb889744b0
author Ömer Sinan Ağacan <omersa@google.com> Tue Oct 18 08:05:13 2022 +0200
committer GitHub <noreply@github.com> Tue Oct 18 09:05:13 2022 +0300
tree e07644d499bee6e7dc15a2a30ad57d3da6819245
parent 1d175bef6043bc4bdef5970f6dbd6d3001124373

Fix `null` handling in proto3 JSON deserializer (#763)

[proto3 JSON spec][1] says this about `null` values:

> If a value is missing in the JSON-encoded data or if its value is
> null, it will be interpreted as the appropriate default value when
> parsed into a protocol buffer

proto3 spec does not talk about presence, but in an internal spec we
have this about proto3 JSON null values:

> When parsing, a “null” value is accepted for all field types. It will
> be treated as if the field has the default value (the field itself
> would not be set, but its getter will return the default value for
> proto3).

So we shouldn't be initializing the fields with `null` values. The
"interpreted as default value" part in the public spec is already
handled by the getters.

With this #760 is no longer an issue as we don't generate empty message
for the field value when we have a message-field.

We will still accept proto3 JSON message encodings with missing
`required` fields, but that's by design. We don't check for `required`
fields until `GeneratedMessage.check` is called.

Closes #760

[1]: https://developers.google.com/protocol-buffers/docs/proto3#json