Make RequestFlags immutable with replace method#23
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xmartinez
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LG!
nit: We should also update README.md (it references flags.copy()).
| /// | ||
| /// Note: passing `None` explicitly for an optional field (e.g. `cache_ttl=None`) | ||
| /// keeps the existing value rather than unsetting it. To unset an optional field, | ||
| /// construct a new `RequestFlags` directly. |
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This could be confusing, but for common use cases (e.g., ttl override), it should be fine.
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Motivation / Description
The
RequestFlagsclass was previously mutable, allowing fields to be modified after creation.Routers and layers above meta-memcache-socket often share a single request flags object to avoid re-creating it, and we had a bug in the gutter pool where it was modifying the passed request flags that was shared across threads and requests.
This change makes
RequestFlagsimmutable to improve safety and predictability, while providing areplace()method for conveniently creating modified copies.Changes introduced
RequestFlagsimmutable by marking it asfrozenand removing field settersFinaltype annotations to all fields in the Python type stubcopy()method with a newreplace()method that accepts keyword arguments for selectively overriding fieldsreplace()method preserves existing values for unspecified fields and handles optional fields appropriatelyreplace()functionality and immutability behavior