Cross-Layer Annotations

中文版

ExposeAs

from pydantic_resolve import ExposeAs

ExposeAs(alias: str)

Exposes a field's value to descendant nodes under the given alias. Descendants can read it via ancestor_context.

class SprintView(BaseModel):
    name: Annotated[str, ExposeAs('sprint_name')]

class TaskView(BaseModel):
    def post_full_title(self, ancestor_context):
        return f"{ancestor_context['sprint_name']} / {self.title}"

Aliases should be globally unique within the resolved tree.

SendTo

from pydantic_resolve import SendTo

SendTo(name: str | tuple[str, ...])

Marks a field's value to be sent upward to a parent collector. Accepts a single collector name or a tuple of names.

# Single target
class TaskView(BaseModel):
    owner: Annotated[Optional[User], SendTo('contributors')] = None

# Multiple targets
class TaskView(BaseModel):
    owner: Annotated[Optional[User], SendTo(('contributors', 'all_users'))] = None

Collector

from pydantic_resolve import Collector

Collector(alias: str, flat: bool = False)

Collects values from descendant nodes marked with SendTo. Used in post_* methods.

class SprintView(BaseModel):
    contributors: list[User] = []

    def post_contributors(self, collector=Collector('contributors')):
        return collector.values()

Parameter	Type	Default	Description
alias	str	required	Must match the SendTo name
flat	bool	False	Use extend instead of append for list values

flat parameter

• flat=False: collector.values() → [UserA, [UserB, UserC]]
• flat=True: collector.values() → [UserA, UserB, UserC]

ICollector

from pydantic_resolve import ICollector

class ICollector:
    alias: str

    def add(self, val) -> None: ...
    def values(self) -> Any: ...

Base interface for custom collectors. Implement add and values:

class CounterCollector(ICollector):
    def __init__(self, alias):
        self.alias = alias
        self.counter = 0

    def add(self, val):
        self.counter += len(val) if isinstance(val, list) else 1

    def values(self):
        return self.counter