Commonize how SAM transform checks are done (#4043)

Author: kddejong

src/cfnlint/context/context.py

@@ -19,6 +19,7 @@
     FUNCTIONS,
     PSEUDOPARAMS,
     REGION_PRIMARY,
+    TRANSFORM_LANGUAGE_EXTENSION,
     TRANSFORM_SAM,
 )
 from cfnlint.schema import PROVIDER_SCHEMA_MANAGER, AttributeDict
@@ -52,10 +53,11 @@ def __post_init__(self, transforms) -> None:
         )
 
     def has_language_extensions_transform(self):
-        lang_extensions_transform = "AWS::LanguageExtensions"
-        return bool(lang_extensions_transform in self._transforms)
+        return bool(TRANSFORM_LANGUAGE_EXTENSION in self._transforms)
 
     def has_sam_transform(self):
+        # this function will always return False as SAM transform
+        # will eliminate itself when the transform is done
         return bool(TRANSFORM_SAM in self._transforms)
 
 

src/cfnlint/helpers.py

@@ -357,6 +357,7 @@
 BOOLEAN_STRINGS = frozenset(list(BOOLEAN_STRINGS_TRUE) + list(BOOLEAN_STRINGS_FALSE))
 
 TRANSFORM_SAM = "AWS::Serverless-2016-10-31"
+TRANSFORM_LANGUAGE_EXTENSION = "AWS::LanguageExtensions"
 
 
 # pylint: disable=missing-class-docstring

src/cfnlint/rules/functions/ToJsonString.py

@@ -7,7 +7,7 @@
 
 from typing import Any
 
-from cfnlint.helpers import PSEUDOPARAMS
+from cfnlint.helpers import PSEUDOPARAMS, TRANSFORM_LANGUAGE_EXTENSION
 from cfnlint.jsonschema import ValidationError, ValidationResult, Validator
 from cfnlint.rules.functions._BaseFn import BaseFn
 
@@ -64,7 +64,7 @@ def fn_tojsonstring(
             yield ValidationError(
                 (
                     f"{self.fn.name} is not supported without "
-                    "'AWS::LanguageExtensions' transform"
+                    f"{TRANSFORM_LANGUAGE_EXTENSION!r} transform"
                 ),
                 validator=self.fn.py,
                 rule=self,

src/cfnlint/rules/parameters/Used.py

@@ -20,9 +20,9 @@ class Used(CloudFormationLintRule):
     tags = ["parameters"]
 
     def match(self, cfn: Template) -> RuleMatches:
-        if cfn.transform_pre["Transform"]:
-            return []
         matches: RuleMatches = []
+        if cfn.transform_pre["Transform"]:
+            return matches
 
         le_refs = None
         if cfn.has_language_extensions_transform():

src/cfnlint/rules/resources/HardCodedArnProperties.py

@@ -6,7 +6,6 @@
 import regex as re
 
 from cfnlint._typing import RuleMatches
-from cfnlint.helpers import TRANSFORM_SAM
 from cfnlint.rules import CloudFormationLintRule, RuleMatch
 from cfnlint.template import Template
 
@@ -86,9 +85,7 @@ def match_values(self, cfn):
     def match(self, cfn: Template) -> RuleMatches:
         matches: RuleMatches = []
 
-        transforms = cfn.transform_pre["Transform"]
-        transforms = transforms if isinstance(transforms, list) else [transforms]
-        if TRANSFORM_SAM in cfn.transform_pre["Transform"]:
+        if cfn.has_serverless_transform():
             return matches
 
         # Get a list of paths to every leaf node string containing at least one ${parameter}

src/cfnlint/rules/resources/ServerlessTransform.py

@@ -31,7 +31,7 @@ def validate(
         if not validator.is_type(instance, "string"):
             return
 
-        if validator.context.transforms.has_sam_transform():
+        if validator.cfn.has_serverless_transform():
             return
 
         if instance.startswith("AWS::Serverless::"):

src/cfnlint/rules/resources/iam/Permissions.py

@@ -10,7 +10,7 @@
 import regex as re
 
 from cfnlint.data import AdditionalSpecs
-from cfnlint.helpers import TRANSFORM_SAM, ensure_list, load_resource
+from cfnlint.helpers import ensure_list, load_resource
 from cfnlint.jsonschema import ValidationError, ValidationResult, Validator
 from cfnlint.rules.jsonschema.CfnLintKeyword import CfnLintKeyword
 
@@ -41,7 +41,7 @@ def validate(
     ) -> ValidationResult:
         # Escape validation when using SAM transforms as a result of
         # https://github.com/aws/serverless-application-model/issues/3633
-        if TRANSFORM_SAM in validator.cfn.transform_pre["Transform"]:
+        if validator.cfn.has_serverless_transform():
             return
 
         actions = ensure_list(instance)

src/cfnlint/template/template.py

@@ -142,28 +142,18 @@ def has_language_extensions_transform(self) -> bool:
         Returns:
             bool: True if the AWS::LanguageExtensions transform is declared, False otherwise.
         """
-        lang_extensions_transform = "AWS::LanguageExtensions"
-        transform_declaration = self.transform_pre["Transform"]
-        transform_type = (
-            transform_declaration
-            if isinstance(transform_declaration, list)
-            else [transform_declaration]
+        return bool(
+            cfnlint.helpers.TRANSFORM_LANGUAGE_EXTENSION
+            in self.transform_pre["Transform"]
         )
-        return bool(lang_extensions_transform in transform_type)
 
     def has_serverless_transform(self) -> bool:
         """Check if the template has the AWS::Serverless-2016-10-31 transform declared.
 
         Returns:
             bool: True if the AWS::Serverless-2016-10-31 transform is declared, False otherwise.
         """
-        transform_declaration = self.transform_pre["Transform"]
-        transform_type = (
-            transform_declaration
-            if isinstance(transform_declaration, list)
-            else [transform_declaration]
-        )
-        return bool(cfnlint.helpers.TRANSFORM_SAM in transform_type)
+        return bool(cfnlint.helpers.TRANSFORM_SAM in self.transform_pre["Transform"])
 
     def is_cdk_template(self) -> bool:
         """Check if the template was created by the AWS Cloud Development Kit (CDK).

src/cfnlint/template/transforms/_sam.py

@@ -17,7 +17,12 @@
 
 from cfnlint.data import Serverless
 from cfnlint.decode.utils import convert_dict
-from cfnlint.helpers import ensure_list, is_function, load_resource
+from cfnlint.helpers import (
+    TRANSFORM_LANGUAGE_EXTENSION,
+    ensure_list,
+    is_function,
+    load_resource,
+)
 from cfnlint.template.transforms._types import TransformResult
 
 LOGGER = logging.getLogger("cfnlint")
@@ -148,7 +153,7 @@ def _replace_variables_with_language_extension(self):
         transforms = self._template.get("Transform", [])
 
         transforms = ensure_list(transforms)
-        if "AWS::LanguageExtensions" in transforms:
+        if TRANSFORM_LANGUAGE_EXTENSION in transforms:
             parameters = {}
             for k, v in self._template.get("Parameters", {}).items():
                 p_type = v.get("Type")

src/cfnlint/template/transforms/transform.py

@@ -11,7 +11,11 @@
 from cfnlint.conditions import Conditions
 from cfnlint.context import create_context_for_template
 from cfnlint.graph import Graph
-from cfnlint.helpers import TRANSFORM_SAM, format_json_string
+from cfnlint.helpers import (
+    TRANSFORM_LANGUAGE_EXTENSION,
+    TRANSFORM_SAM,
+    format_json_string,
+)
 from cfnlint.match import Match
 from cfnlint.template.transforms._language_extensions import language_extension
 from cfnlint.template.transforms._sam import sam
@@ -24,7 +28,7 @@ class Transform:
     def __init__(self) -> None:
         self.transforms: Mapping[str, Callable[[Any], TransformResult]] = {
             TRANSFORM_SAM: sam,
-            "AWS::LanguageExtensions": language_extension,
+            TRANSFORM_LANGUAGE_EXTENSION: language_extension,
         }
 
     def transform(self, cfn: Any) -> list[Match]:

test/unit/rules/resources/test_serverless_transform.py

@@ -56,6 +56,7 @@ def rule():
     ],
     indirect=["template"],
 )
-def test_validate(name, instance, template, expected, rule, validator):
+def test_validate(name, instance, template, expected, rule, validator, cfn):
+    print(cfn.transform_pre)
     errors = list(rule.validate(validator, False, instance, {}))
     assert errors == expected, f"Test {name!r} got {errors!r}"