info.field_resolution

Overview

Shared resolution of a serializer field's backing Django model field.

Used by both ModelInfoSerializer.get_model_fields_data (to derive type_db/type_model metadata) and the vueda_info system check (to warn about a path that fails to resolve), so the two cannot disagree about whether a given field's path resolves.

field.source and a model's <field>_lookup_expression are resolved through two different mechanisms, because they have different runtime semantics:

• field.source is DRF's own attribute lookup (rest_framework.fields.get_attribute), which chains plain getattr() across source.split('.'). It is walked here the same way, so this module never claims a source resolves when DRF's own runtime traversal would not reach it.
• A <field>_lookup_expression is fed directly to models.F() for queryset annotation (see annotate_formatted_name in vueda.core.models) and to Django admin's lookup_field(). It is resolved here through Django's own query-expression machinery (F(...).resolve_expression), the same mechanism annotate_formatted_name uses, so this module never claims an expression is broken when the ORM would actually accept it (a relation, or a transform such as "__year").

resolve_serializer_field_model_field

Resolve the concrete, terminal Django model field a serializer field's value is drawn from.

Returns a (model_field, unresolved_path) pair:

• A field bound to the whole object (field.source == "*") is never model-backed by design. SerializerMethodField forces this; a plain Field subclass that computes its own value from the instance can set it explicitly the same way (ObjectRevisionField in vueda.history.revision does). Returns (None, None) -- callers must not treat this as an unresolved path worth a warning.
• A model declaring <field_name>_lookup_expression (the formatted_name mechanism) takes priority over field.source and is resolved via Django's own query-expression semantics (see _resolve_lookup_expression).
• Otherwise, field.source (a dotted path for a nested/traversing source, or a plain field name for the common case) is walked via DRF's own attribute-lookup semantics (see _walk_source).

unresolved_path carries the path that failed to resolve, for the system check to name in its warning. A field is only exempt from reporting when it opts out of model-backing by one of two explicit conventions -- never merely because field.source happened to default to field_name rather than being set explicitly:

• field.source == "*" (SerializerMethodField forces this; a plain Field subclass that computes its own value can set it the same way -- ObjectRevisionField, AvailableActionsField, and AvailableTransitionField all do, since each overrides get_attribute() outright and never reads source at runtime).
• A model defining a callable get_<field_name>(), mirroring the get_formatted_name() convention FormattedNameBaseModel._get_formatted_name already reads this way: a model may opt out of a generated column (for example formatted_name = None) in favor of a plain method, and that method is exactly as legitimate a source of the value as a real column.

Absent either opt-out, an unresolved path is reported regardless of whether field.source was set explicitly or left to DRF's default -- a field name that fails to resolve is exactly as likely to be a typo or a stale rename as an explicit source= that fails partway through a relation, and DRF's default gives no way to tell the difference from the outside.

<field>_lookup_expression is resolved through Django's own query-expression semantics (see _resolve_lookup_expression) rather than _walk_source, since it is fed directly to models.F() for queryset annotation and to Django admin's lookup_field(), both of which resolve purely at the database level and cannot reach a @property or method.

field may be unbound (as returned by a bare serializer_instance.get_fields() call, which does not run DRF's binding step) so field.source may still be None rather than already defaulted to field_name -- this mirrors DRF's own Field.bind() default.

Signature

resolve_serializer_field_model_field(model, field_name, field)

Parameters

Name	Type	Required	Description
model		yes
field_name		yes
field		yes

Source

server/vueda/info/field_resolution.py:91

Source

server/vueda/info/field_resolution.py