Files
lda-wf/src/wf_api/input_expressions.py
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790 lines
27 KiB
Python

from __future__ import annotations
from collections.abc import Mapping, Sequence
from copy import deepcopy
from dataclasses import dataclass, field
from typing import Any, Literal
from jsonschema import Draft202012Validator, ValidationError
from wf_core.models.input_bindings import (
ArrayExpression,
InputExpression,
LiteralExpression,
ObjectExpression,
PathExpression,
)
from .schema_projection import (
JsonObject,
SchemaLocationPart,
_resolve_local_reference,
project_schema_path_to_schema_path,
schema_fragment_at_location,
schema_location_is_explicit,
)
Compatibility = Literal["compatible", "incompatible", "unsupported"]
_COMPOSITION_KEYWORDS = frozenset({"allOf", "anyOf", "oneOf", "if", "then", "else"})
_ANNOTATION_KEYWORDS = frozenset(
{
"title",
"description",
"default",
"examples",
"deprecated",
"readOnly",
"writeOnly",
}
)
_STRUCTURAL_KEYWORDS = frozenset(
{
"type",
"properties",
"required",
"additionalProperties",
"items",
"prefixItems",
"minItems",
"maxItems",
"minLength",
"maxLength",
"pattern",
"format",
"uniqueItems",
"multipleOf",
"minimum",
"maximum",
"exclusiveMinimum",
"exclusiveMaximum",
"const",
"enum",
"$ref",
"$defs",
"definitions",
}
)
_NUMERIC_CONSTRAINT_KEYWORDS = frozenset(
{"minimum", "maximum", "exclusiveMinimum", "exclusiveMaximum"}
)
_MAX_SCHEMA_NORMALIZATION_NODES = 2048
@dataclass
class _SchemaNormalizationContext:
"""Bound recursive local-schema expansion independently of call depth."""
nodes: int = 0
active_refs: set[str] = field(default_factory=set)
def visit(self, label: str) -> None:
self.nodes += 1
if self.nodes > _MAX_SCHEMA_NORMALIZATION_NODES:
raise ValueError(
f"schema normalization exceeds the global node budget at {label}"
)
@dataclass(frozen=True)
class ExpressionProjection:
"""Validated expression plus schemas inferred for missing graph sources."""
input_schema: JsonObject
state_schema: JsonObject
deferred_paths: tuple[str, ...]
def validate_and_project_input_expression(
expression: InputExpression,
*,
target_schema: JsonObject,
input_schema: JsonObject,
state_schema: JsonObject,
target_location: Sequence[SchemaLocationPart] = (),
label: str = "input expression",
) -> ExpressionProjection:
"""Validate one expression and project schemas for undeclared input/state paths.
This is intentionally not a general JSON Schema subtype engine. It handles
finite literals, primitive type widening (integer to number), declared
object/array members, and const/enum subsets. Unsupported composition or
constraints fail closed; context paths are the one deliberate exception
because their schema is only authoritative at runtime.
"""
target_fragment = schema_fragment_at_location(
target_schema,
tuple(target_location),
label="capability input schema",
)
projected_input = deepcopy(input_schema)
projected_state = deepcopy(state_schema)
deferred_paths: list[str] = []
def visit(
current: InputExpression,
fragment: JsonObject,
location: tuple[SchemaLocationPart, ...],
) -> None:
nonlocal projected_input, projected_state
_ensure_supported_schema(fragment, label=_location_label(label, location))
if isinstance(current, LiteralExpression):
try:
Draft202012Validator(fragment).validate(current.value)
except ValidationError as exc:
raise ValueError(
f"{_location_label(label, location)} literal does not satisfy "
f"the target schema: {exc.message}"
) from exc
return
if isinstance(current, PathExpression):
source_path = current.path
source_text = str(source_path)
if source_path.root == "context":
deferred_paths.append(source_text)
return
if source_path.root == "input":
source_document = projected_input
else:
source_document = projected_state
if schema_location_is_explicit(
source_document,
source_path.parts,
label=f"{source_path.root} source schema",
):
source_fragment = schema_fragment_at_location(
source_document,
source_path.parts,
label=f"{source_path.root} source schema",
)
else:
source_fragment = None
if source_fragment is not None:
compatibility = _schema_assignability(
source_fragment,
fragment,
source_label=f"{source_text} source",
target_label=_location_label(label, location),
)
if compatibility == "incompatible":
raise ValueError(
f"{_location_label(label, location)} source path "
f"{source_text!r} is incompatible with its target schema"
)
if compatibility == "unsupported":
raise ValueError(
f"{_location_label(label, location)} source path "
f"{source_text!r} uses an unsupported schema comparison"
)
return
projected = _project_missing_source_schema(
source_document,
source_parts=source_path.parts,
target_document=target_schema,
target_location=location,
)
if source_path.root == "input":
projected_input = projected
else:
projected_state = projected
return
if isinstance(current, ArrayExpression):
_validate_array_length(
current, fragment, label=_location_label(label, location)
)
for index, item in enumerate(current.items):
child = schema_fragment_at_location(
fragment,
(index,),
label=_location_label(label, location),
)
visit(item, child, (*location, index))
return
if isinstance(current, ObjectExpression):
resolved = _resolved_schema(
fragment, label=_location_label(label, location)
)
properties = resolved.get("properties")
declared = properties if isinstance(properties, Mapping) else {}
required = resolved.get("required", [])
if isinstance(required, list):
missing = [name for name in required if name not in current.fields]
if missing:
raise ValueError(
f"{_location_label(label, location)} is missing required "
f"fields {missing!r}"
)
additional = resolved.get("additionalProperties", True)
for name, item in current.fields.items():
if isinstance(declared, Mapping) and name in declared:
child = schema_fragment_at_location(
fragment,
(name,),
label=_location_label(label, location),
)
elif additional is False:
raise ValueError(
f"{_location_label(label, location)} field {name!r} "
"is not allowed by additionalProperties"
)
else:
child = schema_fragment_at_location(
fragment,
(name,),
label=_location_label(label, location),
)
visit(item, child, (*location, name))
return
raise TypeError(f"unsupported input expression {current!r}")
visit(expression, target_fragment, tuple(target_location))
return ExpressionProjection(
input_schema=projected_input,
state_schema=projected_state,
deferred_paths=tuple(deferred_paths),
)
def _validate_array_length(
expression: ArrayExpression,
schema: Mapping[str, Any],
*,
label: str,
) -> None:
resolved = _resolved_schema(schema, label=label)
schema_type = resolved.get("type")
if schema_type is not None and schema_type != "array":
raise ValueError(f"{label} array expression is incompatible with target schema")
minimum = resolved.get("minItems")
maximum = resolved.get("maxItems")
if isinstance(minimum, int) and len(expression.items) < minimum:
raise ValueError(f"{label} requires at least {minimum} array items")
if isinstance(maximum, int) and len(expression.items) > maximum:
raise ValueError(f"{label} allows at most {maximum} array items")
def _project_missing_source_schema(
source_schema: JsonObject,
*,
source_parts: tuple[str, ...],
target_document: JsonObject,
target_location: tuple[SchemaLocationPart, ...],
) -> JsonObject:
"""Copy one target-position schema into an undeclared input/state path."""
target_fragment = schema_fragment_at_location(
target_document,
target_location,
label="capability input schema",
)
source_holder: JsonObject = {
"type": "object",
"properties": {"__wf_expression_value__": target_fragment},
}
for key in ("$defs", "definitions"):
if key in target_document:
source_holder[key] = deepcopy(target_document[key])
return project_schema_path_to_schema_path(
target_schema=source_schema,
source_schema=source_holder,
source_parts=("__wf_expression_value__",),
target_parts=source_parts,
allow_existing_equivalent=True,
)
def _schema_assignability(
source: Mapping[str, Any],
target: Mapping[str, Any],
*,
source_label: str,
target_label: str,
) -> Compatibility:
"""Classify whether every value allowed by ``source`` fits ``target``.
This is deliberately a conservative three-state relation: ``compatible``
proves the subset relation, ``incompatible`` proves a counterexample, and
``unsupported`` means the supported subset of JSON Schema cannot decide.
The caller must reject the last state rather than treating it as success.
"""
try:
source_normalized = _canonical_schema(source, label=source_label)
target_normalized = _canonical_schema(target, label=target_label)
except ValueError:
return "unsupported"
if source_normalized == target_normalized:
return "compatible"
source_values = _finite_schema_values(source_normalized)
target_values = _finite_schema_values(target_normalized)
if source_values is not None:
validator = Draft202012Validator(target_normalized)
if all(validator.is_valid(value) for value in source_values):
return "compatible"
return "incompatible"
if target_values is not None:
return "unsupported"
source_types = _schema_types(source_normalized)
target_types = _schema_types(target_normalized)
if source_types is None or target_types is None:
if not target_normalized:
return "compatible"
return "unsupported"
if not _types_assignable(source_types, target_types):
return "incompatible"
if source_types & {"object"} or target_types & {"object"}:
return _object_assignability(
source_normalized, target_normalized, source_label, target_label
)
if source_types & {"array"} or target_types & {"array"}:
return _array_assignability(
source_normalized, target_normalized, source_label, target_label
)
constraint_keys = (set(source_normalized) | set(target_normalized)) - {
"type",
"const",
"enum",
}
unsupported_constraints = constraint_keys - _NUMERIC_CONSTRAINT_KEYWORDS
if unsupported_constraints:
return "unsupported"
return _numeric_constraint_assignability(source_normalized, target_normalized)
def _object_assignability(
source: Mapping[str, Any],
target: Mapping[str, Any],
source_label: str,
target_label: str,
) -> Compatibility:
source_properties = source.get("properties", {})
target_properties = target.get("properties", {})
if not isinstance(source_properties, Mapping) or not isinstance(
target_properties, Mapping
):
return "unsupported"
source_required = set(source.get("required", []))
target_required = set(target.get("required", []))
if not target_required.issubset(source_required):
return "incompatible"
for name, source_child in source_properties.items():
if name in target_properties:
if not isinstance(source_child, Mapping) or not isinstance(
target_properties[name], Mapping
):
return "unsupported"
status = _schema_assignability(
source_child,
target_properties[name],
source_label=f"{source_label}.{name}",
target_label=f"{target_label}.{name}",
)
if status != "compatible":
return status
elif target.get("additionalProperties") is False:
return "incompatible"
elif isinstance(target.get("additionalProperties"), Mapping):
status = _schema_assignability(
source_child,
target["additionalProperties"],
source_label=f"{source_label}.{name}",
target_label=f"{target_label}.additionalProperties",
)
if status != "compatible":
return status
source_additional = source.get("additionalProperties", True)
target_additional = target.get("additionalProperties", True)
if target_additional is False and source_additional is not False:
return "incompatible"
for name, target_child in target_properties.items():
if name in source_properties:
continue
if source_additional is False:
continue
if isinstance(source_additional, Mapping):
status = _schema_assignability(
source_additional,
target_child,
source_label=f"{source_label}.additionalProperties",
target_label=f"{target_label}.{name}",
)
if status != "compatible":
return status
else:
return "unsupported"
if isinstance(target_additional, Mapping):
if isinstance(source_additional, Mapping):
return _schema_assignability(
source_additional,
target_additional,
source_label=f"{source_label}.additionalProperties",
target_label=f"{target_label}.additionalProperties",
)
if source_additional is True:
return "unsupported"
return "compatible"
def _array_assignability(
source: Mapping[str, Any],
target: Mapping[str, Any],
source_label: str,
target_label: str,
) -> Compatibility:
source_min = source.get("minItems")
target_min = target.get("minItems")
if isinstance(target_min, int) and (
(not isinstance(source_min, int) and target_min > 0)
or isinstance(source_min, int)
and source_min < target_min
):
return "incompatible"
source_max = source.get("maxItems")
target_max = target.get("maxItems")
if isinstance(target_max, int) and (
not isinstance(source_max, int) or source_max > target_max
):
return "incompatible"
source_prefix = source.get("prefixItems")
target_prefix = target.get("prefixItems")
if source_prefix is not None or target_prefix is not None:
if not isinstance(source_prefix, list) or not isinstance(target_prefix, list):
return "unsupported"
if len(source_prefix) != len(target_prefix):
return "unsupported"
for index, (source_item, target_item) in enumerate(
zip(source_prefix, target_prefix, strict=True)
):
if not isinstance(source_item, Mapping) or not isinstance(
target_item, Mapping
):
return "unsupported"
status = _schema_assignability(
source_item,
target_item,
source_label=f"{source_label}.prefixItems[{index}]",
target_label=f"{target_label}.prefixItems[{index}]",
)
if status != "compatible":
return status
source_items = source.get("items", True)
target_items = target.get("items", True)
if source_items is False:
return "compatible"
if target_items is False:
return "incompatible"
if target_items is True:
return "compatible"
if source_items is True:
return "unsupported"
if isinstance(source_items, Mapping) and isinstance(target_items, Mapping):
return _schema_assignability(
source_items,
target_items,
source_label=f"{source_label}.items",
target_label=f"{target_label}.items",
)
return "unsupported"
def _types_assignable(source: set[str], target: set[str]) -> bool:
return all(
any(
source_type == target_type
or source_type == "integer"
and target_type == "number"
for target_type in target
)
for source_type in source
)
def _finite_schema_values(schema: Mapping[str, Any]) -> list[Any] | None:
"""Return the finite value set represented by a const or enum constraint."""
if "const" in schema:
value = schema["const"]
accepted = schema.get("enum")
if isinstance(accepted, list) and value not in accepted:
return []
return [value]
values = schema.get("enum")
if isinstance(values, list):
return values
return None
def _numeric_constraint_assignability(
source: Mapping[str, Any], target: Mapping[str, Any]
) -> Compatibility:
"""Compare the supported numeric interval constraints conservatively."""
source_lower = _numeric_bound(source, lower=True)
target_lower = _numeric_bound(target, lower=True)
if target_lower is not None and (
source_lower is None or not _lower_bound_contains(source_lower, target_lower)
):
return "incompatible"
source_upper = _numeric_bound(source, lower=False)
target_upper = _numeric_bound(target, lower=False)
if target_upper is not None and (
source_upper is None or not _upper_bound_contains(source_upper, target_upper)
):
return "incompatible"
return "compatible"
def _numeric_bound(
schema: Mapping[str, Any], *, lower: bool
) -> tuple[int | float, bool] | None:
names = (
("minimum", "exclusiveMinimum") if lower else ("maximum", "exclusiveMaximum")
)
candidates = [
(schema[name], name.startswith("exclusive"))
for name in names
if isinstance(schema.get(name), (int, float))
and not isinstance(schema.get(name), bool)
]
if not candidates:
return None
return (
max(candidates, key=lambda item: (item[0], item[1]))
if lower
else min(candidates, key=lambda item: (item[0], not item[1]))
)
def _lower_bound_contains(
source: tuple[int | float, bool], target: tuple[int | float, bool]
) -> bool:
if source[0] != target[0]:
return source[0] > target[0]
return source[1] or not target[1]
def _upper_bound_contains(
source: tuple[int | float, bool], target: tuple[int | float, bool]
) -> bool:
if source[0] != target[0]:
return source[0] < target[0]
return source[1] or not target[1]
def _schema_types(schema: Mapping[str, Any]) -> set[str] | None:
value = schema.get("type")
if isinstance(value, str):
return {value}
if isinstance(value, list) and all(isinstance(item, str) for item in value):
return set(value)
return None
def _ensure_supported_schema(schema: Mapping[str, Any], *, label: str) -> None:
_canonical_schema(schema, label=label)
def validate_schema_references(schema: Mapping[str, Any], *, label: str) -> None:
"""Resolve schema references without imposing expression-keyword limits."""
_validate_schema_references(
schema,
root_schema=schema,
label=label,
context=_SchemaNormalizationContext(),
)
def _validate_schema_references(
schema: Mapping[str, Any],
*,
root_schema: Mapping[str, Any],
label: str,
context: _SchemaNormalizationContext,
) -> None:
context.visit(label)
reference = schema.get("$ref")
if isinstance(reference, str):
if reference in context.active_refs:
raise ValueError(f"cyclic local schema reference {reference!r} at {label}")
context.active_refs.add(reference)
try:
resolved = _resolve_local_reference(root_schema, schema, label=label)
_validate_schema_references(
resolved,
root_schema=root_schema,
label=label,
context=context,
)
finally:
context.active_refs.remove(reference)
return
properties = schema.get("properties")
if isinstance(properties, Mapping):
for name, child in properties.items():
if isinstance(name, str) and isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.{name}",
context=context,
)
for key in ("items", "additionalProperties"):
child = schema.get(key)
if isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.{key}",
context=context,
)
prefix_items = schema.get("prefixItems")
if isinstance(prefix_items, list):
for index, child in enumerate(prefix_items):
if isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.prefixItems[{index}]",
context=context,
)
for key in ("allOf", "anyOf", "oneOf"):
branches = schema.get(key)
if isinstance(branches, list):
for index, child in enumerate(branches):
if isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.{key}[{index}]",
context=context,
)
for key in ("if", "then", "else"):
child = schema.get(key)
if isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.{key}",
context=context,
)
for key in ("$defs", "definitions"):
definitions = schema.get(key)
if isinstance(definitions, Mapping):
for name, child in definitions.items():
if isinstance(name, str) and isinstance(child, Mapping):
_validate_schema_references(
child,
root_schema=root_schema,
label=f"{label}.{key}.{name}",
context=context,
)
def _resolved_schema(
schema: Mapping[str, Any],
*,
label: str,
root_schema: Mapping[str, Any] | None = None,
) -> Mapping[str, Any]:
resolved = _resolve_local_reference(
root_schema if root_schema is not None else schema,
schema,
label=label,
)
if any(keyword in resolved for keyword in _COMPOSITION_KEYWORDS):
raise ValueError(f"unsupported schema composition at {label}")
return resolved
def _canonical_schema(
schema: Mapping[str, Any],
*,
label: str,
root_schema: Mapping[str, Any] | None = None,
context: _SchemaNormalizationContext | None = None,
) -> dict[str, Any]:
normalization = context or _SchemaNormalizationContext()
normalization.visit(label)
canonical_root = root_schema if root_schema is not None else schema
reference = schema.get("$ref")
if isinstance(reference, str):
if reference in normalization.active_refs:
raise ValueError(f"cyclic local schema reference {reference!r} at {label}")
normalization.active_refs.add(reference)
try:
return _canonical_schema(
_resolved_schema(schema, label=label, root_schema=canonical_root),
label=label,
root_schema=canonical_root,
context=normalization,
)
finally:
normalization.active_refs.remove(reference)
resolved = _resolved_schema(schema, label=label, root_schema=canonical_root)
if any(keyword in resolved for keyword in _COMPOSITION_KEYWORDS):
raise ValueError(f"unsupported schema composition at {label}")
unknown = set(resolved) - _STRUCTURAL_KEYWORDS - _ANNOTATION_KEYWORDS
if unknown:
raise ValueError(
f"unsupported schema keyword(s) at {label}: {sorted(unknown)!r}"
)
canonical: dict[str, Any] = {}
for key, value in resolved.items():
if key in _ANNOTATION_KEYWORDS or key in {"$defs", "definitions"}:
continue
if key == "properties" and isinstance(value, Mapping):
canonical[key] = {
name: _canonical_schema(
child,
label=f"{label}.{name}",
root_schema=canonical_root,
context=normalization,
)
for name, child in value.items()
if isinstance(name, str) and isinstance(child, Mapping)
}
elif key in {"items", "additionalProperties"} and isinstance(value, Mapping):
canonical[key] = _canonical_schema(
value,
label=f"{label}.{key}",
root_schema=canonical_root,
context=normalization,
)
elif key == "prefixItems" and isinstance(value, list):
canonical[key] = [
_canonical_schema(
child,
label=f"{label}.prefixItems[{index}]",
root_schema=canonical_root,
context=normalization,
)
for index, child in enumerate(value)
if isinstance(child, Mapping)
]
elif key == "required" and isinstance(value, list):
canonical[key] = sorted(value)
else:
canonical[key] = deepcopy(value)
return canonical
def _location_label(label: str, location: Sequence[SchemaLocationPart]) -> str:
result = label
for part in location:
if isinstance(part, int):
result += f"[{part}]"
else:
result += f".{part}"
return result