unstringify data field on read.

[yonghongren]

When a model's field has no property definition, we unconditionally stringify the field on write. If the field data is a string, it gets quoted again. On read we don't undo the stringification. A string data field becomes a string with extra quotes. read & write need be symmetrical.

Description

Related issues

• None

Checklist

• [ ] New tests added or existing tests modified to cover all changes
• [ ] Code conforms with the style guide