Update regex for FnSub

aws-cloudformation · Dec 12, 2024 · 6ebbbd6 · 6ebbbd6
1 parent 310beb4
commit 6ebbbd6
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/src/cfnlint/helpers.py b/src/cfnlint/helpers.py
@@ -136,7 +136,7 @@
 REGEX_DYN_REF_SSM_SECURE = re.compile(
     r"^.*{{resolve:ssm-secure:[a-zA-Z0-9_\.\-/]+(:\d+)?}}.*$"
 )
-REGEX_SUB_PARAMETERS = re.compile(r"\${([^!].*?)}")
+REGEX_SUB_PARAMETERS = re.compile(r"\${\s*([^!\s].*?)\s*}")
 
 FUNCTIONS = frozenset(
     [

diff --git a/test/unit/rules/functions/test_sub.py b/test/unit/rules/functions/test_sub.py
@@ -162,6 +162,18 @@ def context(cfn):
             {"type": "string"},
             [],
         ),
+        (
+            "Valid Fn::Sub with a space and escape char",
+            {"Fn::Sub": "${ !Foo }"},
+            {"type": "string"},
+            [],
+        ),
+        (
+            "Valid Fn::Sub with a space and no escape char",
+            {"Fn::Sub": "${ AWS::AccountId }"},
+            {"type": "string"},
+            [],
+        ),
         (
             "Invalid Fn::Sub with a too to many elements",
             {"Fn::Sub": ["${foo}", {"foo": "bar"}, {}]},