v2.13.0b3 2026-03-31

@boosterl

What's Changed

Add ascii_only option to StringConstraints by @ai-man-codes in #12907
Support exclude_if in computed fields by @andresliszt in #12748
Push down constraints in unions involving MISSING sentinel by @Viicos in #12908

Track extra fields set after init in model_fields_set by @navalprakhar in #12817
Do not include annotations that are not part of named tuple fields by @galuszkak in #12951
No longer fall back to trying all union members when the variant selected by discriminator fails to serialize by @navalprakhar in #12825

Support discriminator metadata outside union type alias by @Viicos in #12785
Respect extras_schema when only extra_fields_behavior is set on the config in JSON Schema generation for typed dictionaries by @Viicos in #12810
Ensure __pydantic_private__ is set in model_construct() with user-defined model_post_init() by @nightcityblade in #12816
Handle all schema generation errors in InstanceOf by @Viicos in #12705
Allow dynamic models created with create_model() to be used as annotations in the Mypy plugin by @Br1an67 in #12879
Check for PlaceholderNode in Mypy plugin by @Viicos in #12929
Try other branches in smart union in case of omit errors by @mikeedjones in #12758
Patch unset attributes with MISSING during model serialization with exclude_unset by @davidhewitt in #12905
Ensure custom __init__() is called when using model_validate_strings() by @siewcapital in #12897

Full Changelog: v2.13.0b2...v2.13.0b3