Update mappings to support transforms at the root level (#3439)

Author: kddejong

src/cfnlint/context/_mappings.py

@@ -0,0 +1,100 @@
+"""
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: MIT-0
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass, field
+from typing import Any, Iterator
+
+LOGGER = logging.getLogger(__name__)
+
+
+@dataclass(frozen=True)
+class Mappings:
+    """
+    This class holds a mapping
+    """
+
+    maps: dict[str, Map] = field(init=True, default_factory=dict)
+    is_transform: bool = field(init=True, default=False)
+
+    @classmethod
+    def create_from_dict(cls, instance: Any) -> Mappings:
+
+        if not isinstance(instance, dict):
+            return cls({})
+        try:
+            result = {}
+            is_transform = False
+            for k, v in instance.items():
+                if k == "Fn::Transform":
+                    is_transform = True
+                else:
+                    result[k] = Map.create_from_dict(v)
+            return cls(result, is_transform)
+        except (ValueError, AttributeError) as e:
+            LOGGER.debug(e, exc_info=True)
+            return cls({})
+
+
+@dataclass(frozen=True)
+class _MappingSecondaryKey:
+    """
+    This class holds a mapping value
+    """
+
+    keys: dict[str, list[Any] | str | int | float] = field(
+        init=True, default_factory=dict
+    )
+    is_transform: bool = field(init=True, default=False)
+
+    def value(self, secondary_key: str):
+        if secondary_key not in self.keys:
+            raise KeyError(secondary_key)
+        return self.keys[secondary_key]
+
+    @classmethod
+    def create_from_dict(cls, instance: Any) -> _MappingSecondaryKey:
+        if not isinstance(instance, dict):
+            return cls({})
+        is_transform = False
+        keys = {}
+        for k, v in instance.items():
+            if k == "Fn::Transform":
+                is_transform = True
+            elif isinstance(v, (str, list, int, float)):
+                keys[k] = v
+            else:
+                continue
+        return cls(keys, is_transform)
+
+
+@dataclass(frozen=True)
+class Map:
+    """
+    This class holds a mapping
+    """
+
+    keys: dict[str, _MappingSecondaryKey] = field(init=True, default_factory=dict)
+    is_transform: bool = field(init=True, default=False)
+
+    def find_in_map(self, top_key: str, secondary_key: str) -> Iterator[Any]:
+        if top_key not in self.keys:
+            raise KeyError(top_key)
+        yield self.keys[top_key].value(secondary_key)
+
+    @classmethod
+    def create_from_dict(cls, instance: Any) -> Map:
+        if not isinstance(instance, dict):
+            return cls({})
+        is_transform = False
+        keys = {}
+        for k, v in instance.items():
+            if k == "Fn::Transform":
+                is_transform = True
+            else:
+                keys[k] = _MappingSecondaryKey.create_from_dict(v)
+        return cls(keys, is_transform)

src/cfnlint/context/context.py

@@ -11,6 +11,7 @@
 from typing import Any, Deque, Iterator, Sequence, Set, Tuple
 
 from cfnlint.context._conditions import Conditions
+from cfnlint.context._mappings import Mappings
 from cfnlint.helpers import (
     BOOLEAN_STRINGS_TRUE,
     FUNCTIONS,
@@ -138,7 +139,7 @@ class Context:
     parameters: dict[str, "Parameter"] = field(init=True, default_factory=dict)
     resources: dict[str, "Resource"] = field(init=True, default_factory=dict)
     conditions: Conditions = field(init=True, default_factory=Conditions)
-    mappings: dict[str, "Map"] = field(init=True, default_factory=dict)
+    mappings: Mappings = field(init=True, default_factory=Mappings)
 
     strict_types: bool = field(init=True, default=True)
 
@@ -374,61 +375,6 @@ def ref(self, context: Context) -> Iterator[Any]:
         yield
 
 
-@dataclass
-class _MappingSecondaryKey:
-    """
-    This class holds a mapping value
-    """
-
-    keys: dict[str, list[Any] | str | int | float] = field(
-        init=False, default_factory=dict
-    )
-    instance: InitVar[Any]
-    is_transform: bool = field(init=False, default=False)
-
-    def __post_init__(self, instance) -> None:
-        if not isinstance(instance, dict):
-            raise ValueError("Secondary keys must be a object")
-        for k, v in instance.items():
-            if k == "Fn::Transform":
-                self.is_transform = True
-                continue
-            if isinstance(v, (str, list, int, float)):
-                self.keys[k] = v
-            else:
-                raise ValueError("Third keys must not be an object")
-
-    def value(self, secondary_key: str):
-        if secondary_key not in self.keys:
-            raise KeyError(secondary_key)
-        return self.keys[secondary_key]
-
-
-@dataclass
-class Map:
-    """
-    This class holds a mapping
-    """
-
-    keys: dict[str, _MappingSecondaryKey] = field(init=False, default_factory=dict)
-    resource: InitVar[Any]
-    is_transform: bool = field(init=False, default=False)
-
-    def __post_init__(self, mapping) -> None:
-        if not isinstance(mapping, dict):
-            raise ValueError("Mapping must be a object")
-        for k, v in mapping.items():
-            if k == "Fn::Transform":
-                self.is_transform = True
-            else:
-                self.keys[k] = _MappingSecondaryKey(v)
-
-    def find_in_map(self, top_key: str, secondary_key: str) -> Iterator[Any]:
-        if top_key not in self.keys:
-            raise KeyError(top_key)
-        yield self.keys[top_key].value(secondary_key)
-
-
 def _init_parameters(parameters: Any) -> dict[str, Parameter]:
     obj = {}
     if not isinstance(parameters, dict):
@@ -460,19 +406,6 @@ def _init_transforms(transforms: Any) -> Transforms:
     return Transforms([])
 
 
-def _init_mappings(mappings: Any) -> dict[str, Map]:
-    obj = {}
-    if not isinstance(mappings, dict):
-        raise ValueError("Mappings must be a object")
-    for k, v in mappings.items():
-        try:
-            obj[k] = Map(v)
-        except ValueError:
-            pass
-
-    return obj
-
-
 def create_context_for_template(cfn):
     parameters = {}
     try:
@@ -494,11 +427,7 @@ def create_context_for_template(cfn):
     except (ValueError, AttributeError):
         pass
 
-    mappings = {}
-    try:
-        mappings = _init_mappings(cfn.template.get("Mappings", {}))
-    except (ValueError, AttributeError):
-        pass
+    mappings = Mappings.create_from_dict(cfn.template.get("Mappings", {}))
 
     return Context(
         parameters=parameters,

src/cfnlint/jsonschema/_resolvers_cfn.py

@@ -54,11 +54,13 @@ def find_in_map(validator: Validator, instance: Any) -> ResolutionResult:
                     ), None
                 default_value_found = True
 
-    if not default_value_found and not validator.context.mappings:
+    if not default_value_found and not validator.context.mappings.maps:
+        if validator.context.mappings.is_transform:
+            return
         yield None, validator, ValidationError(
             (
                 f"{instance[0]!r} is not one of "
-                f"{list(validator.context.mappings.keys())!r}"
+                f"{list(validator.context.mappings.maps.keys())!r}"
             ),
             path=deque([0]),
         )
@@ -71,13 +73,13 @@ def find_in_map(validator: Validator, instance: Any) -> ResolutionResult:
         )
         and validator.is_type(instance[2], "string")
     ):
-        map = validator.context.mappings.get(instance[0])
+        map = validator.context.mappings.maps.get(instance[0])
         if map is None:
             if not default_value_found:
                 yield None, validator, ValidationError(
                     (
                         f"{instance[0]!r} is not one of "
-                        f"{list(validator.context.mappings.keys())!r}"
+                        f"{list(validator.context.mappings.maps.keys())!r}"
                     ),
                     path=deque([0]),
                 )

src/cfnlint/rules/mappings/Used.py

@@ -4,6 +4,7 @@
 """
 
 from cfnlint._typing import RuleMatches
+from cfnlint.helpers import is_function
 from cfnlint.rules import CloudFormationLintRule, RuleMatch
 from cfnlint.template import Template
 
@@ -22,6 +23,12 @@ def match(self, cfn: Template) -> RuleMatches:
         findinmap_mappings = []
 
         mappings = cfn.template.get("Mappings", {})
+        k, _ = is_function(mappings)
+        if k == "Fn::Transform":
+            self.logger.debug(
+                (f"Mapping Name has a transform. Disabling check {self.id!r}"),
+            )
+            return matches
 
         if mappings:
             # Get all "FindInMaps" that reference a Mapping

test/unit/module/context/test_create_context.py

@@ -63,7 +63,7 @@
                     },
                 },
             },
-            _Counts(resources=1, parameters=1, conditions=0, mappings=1),
+            _Counts(resources=1, parameters=1, conditions=0, mappings=2),
         ),
         (
             "Invalid mapping second key",
@@ -75,7 +75,7 @@
                     "Map": {"us-east-1": {"foo": "bar"}},
                 },
             },
-            _Counts(resources=0, parameters=0, conditions=0, mappings=1),
+            _Counts(resources=0, parameters=0, conditions=0, mappings=2),
         ),
         (
             "Invalid mapping third key",
@@ -89,7 +89,7 @@
                     "Map": {"us-east-1": {"foo": "bar"}},
                 },
             },
-            _Counts(resources=0, parameters=0, conditions=0, mappings=1),
+            _Counts(resources=0, parameters=0, conditions=0, mappings=2),
         ),
     ],
 )
@@ -101,10 +101,15 @@ def test_create_context(name, instance, counts):
         if i == "conditions":
             assert len(context.conditions.conditions) == getattr(counts, i), (
                 f"Test {name} has {i} {len(getattr(context, i))} "
-                "and expected {getattr(counts, i)}"
+                f"and expected {getattr(counts, i)}"
+            )
+        elif i == "mappings":
+            assert len(context.mappings.maps) == getattr(counts, i), (
+                f"Test {name} has {i} {len(context.mappings.maps)} "
+                f"and expected {getattr(counts, i)}"
             )
         else:
             assert len(getattr(context, i)) == getattr(counts, i), (
                 f"Test {name} has {i} {len(getattr(context, i))} "
-                "and expected {getattr(counts, i)}"
+                f"and expected {getattr(counts, i)}"
             )

test/unit/module/context/test_mappings.py

@@ -5,7 +5,7 @@
 
 import pytest
 
-from cfnlint.context.context import Map
+from cfnlint.context._mappings import Map, Mappings, _MappingSecondaryKey
 
 
 @pytest.mark.parametrize(
@@ -17,7 +17,7 @@
     ],
 )
 def test_mapping_value(name, get_key_1, get_key_2, expected):
-    mapping = Map({"A": {"B": "C"}})
+    mapping = Map.create_from_dict({"A": {"B": "C"}})
 
     if isinstance(expected, Exception):
         with pytest.raises(type(expected)):
@@ -27,10 +27,64 @@ def test_mapping_value(name, get_key_1, get_key_2, expected):
 
 
 def test_transforms():
-    mapping = Map({"A": {"Fn::Transform": "C"}})
+    mapping = Map.create_from_dict({"A": {"Fn::Transform": "C"}})
 
     assert mapping.keys.get("A").is_transform is True
 
-    mapping = Map({"Fn::Transform": {"B": "C"}})
+    mapping = Map.create_from_dict({"Fn::Transform": {"B": "C"}})
 
     assert mapping.is_transform is True
+
+    mapping = Mappings.create_from_dict({"Fn::Transform": {"B": {"C": "D"}}})
+
+    assert mapping.is_transform is True
+
+
+@pytest.mark.parametrize(
+    "name,mappings,expected",
+    [
+        (
+            "Valid mappings",
+            {
+                "A": {"B": {"C": "D"}},
+                "1": {"2": {"3": "4"}},
+                "Z": [],
+                "9": {"8": []},
+                "M": {"N": {"O": {"P": "Q"}}},
+            },
+            Mappings(
+                {
+                    "A": Map({"B": _MappingSecondaryKey({"C": "D"})}),
+                    "1": Map({"2": _MappingSecondaryKey({"3": "4"})}),
+                    "Z": Map({}),
+                    "9": Map({"8": _MappingSecondaryKey({})}),
+                    "M": Map({"N": _MappingSecondaryKey({})}),
+                }
+            ),
+        ),
+        (
+            "Valid mappings with transforms",
+            {
+                "A": {"Fn::Transform": "MyTransform"},
+                "1": {"2": {"Fn::Transform": "MyTransform"}},
+            },
+            Mappings(
+                {
+                    "A": Map({}, True),
+                    "1": Map({"2": _MappingSecondaryKey({}, True)}),
+                }
+            ),
+        ),
+        (
+            "Valid mappings with transforms for mappings",
+            {
+                "Fn::Transform": "MyTransform",
+            },
+            Mappings({}, True),
+        ),
+    ],
+)
+def test_mapping_creation(name, mappings, expected):
+    results = Mappings.create_from_dict(mappings)
+
+    assert results == expected, f"{name!r} failed got {results!r}"