Prevent stack overflow in use-stable-resource-identifiers linter (#10001

)

* Bail walking symbol values when a cycle is detected

* Update cyclic symbol checker not to emit cyclic error message on references that don't participate in the cycle itself.

src/Bicep.Core.IntegrationTests/ScenarioTests.cs

@@ -6,7 +6,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Security.Cryptography;
-using Bicep.Core.CodeAction;
 using Bicep.Core.Diagnostics;
 using Bicep.Core.Resources;
 using Bicep.Core.TypeSystem;
@@ -1894,7 +1893,7 @@ public void Test_Issue2494()
             {
                 ("BCP080", DiagnosticLevel.Error, "The expression is involved in a cycle (\"nameCopy\" -> \"name\")."),
                 ("BCP080", DiagnosticLevel.Error, "The expression is involved in a cycle (\"name\" -> \"nameCopy\")."),
-                ("BCP080", DiagnosticLevel.Error, "The expression is involved in a cycle (\"name\" -> \"nameCopy\").")
+                ("BCP062", DiagnosticLevel.Error, "The referenced declaration with name \"name\" is not valid.")
             });
         }
 
@@ -4346,8 +4345,28 @@ param CertificateSubjects certificateMapping[]
 
             result.Should().GenerateATemplate();
 
-            var evaluated = TemplateEvaluator.Evaluate(result.Template, parameters);            
+            var evaluated = TemplateEvaluator.Evaluate(result.Template, parameters);
             evaluated.Should().HaveValueAtPath("$.outputs['vaultId'].value", "/subscriptions/mySub/resourceGroups/myRg/providers/Microsoft.KeyVault/vaults/myKv");
         }
+
+        // https://github.com/Azure/bicep/issues/9978
+        [TestMethod]
+        public void Test_Issue9978()
+        {
+            var result = CompilationHelper.Compile(@"
+param foo string = guid(foo)
+
+#disable-next-line no-unused-existing-resources
+resource asdf 'Microsoft.Storage/storageAccounts@2022-09-01' existing = {
+  name: foo
+}
+");
+
+            result.Should().HaveDiagnostics(new[]
+            {
+                ("BCP079", DiagnosticLevel.Error, "This expression is referencing its own declaration, which is not allowed."),
+                ("BCP062", DiagnosticLevel.Error, "The referenced declaration with name \"foo\" is not valid."),
+            });
+        }
     }
 }

src/Bicep.Core.Samples/Files/InvalidCycles_CRLF/main.diagnostics.bicep

@@ -52,7 +52,7 @@ var two = one.f
 // #completionTest(17) -> empty
 var twotwo = one.
 //@[04:10) [no-unused-vars (Warning)] Variable "twotwo" is declared but never used. (CodeDescription: bicep core(https://aka.ms/bicep/linter/no-unused-vars)) |twotwo|
-//@[13:16) [BCP080 (Error)] The expression is involved in a cycle ("one" -> "two"). (CodeDescription: none) |one|
+//@[13:16) [BCP062 (Error)] The referenced declaration with name "one" is not valid. (CodeDescription: none) |one|
 //@[17:17) [BCP020 (Error)] Expected a function or property name at this location. (CodeDescription: none) ||
 
 // resource completion cycles

src/Bicep.Core.UnitTests/Diagnostics/LinterRuleTests/UseResourceIdFunctionsRuleTests.cs

@@ -1047,7 +1047,7 @@ param idValue1 string
                     "[2:26] The expression is involved in a cycle (\"v3\" -> \"v2\" -> \"v1\").",
                     "[3:26] The expression is involved in a cycle (\"v1\" -> \"v3\" -> \"v2\").",
                     "[4:26] The expression is involved in a cycle (\"v2\" -> \"v1\" -> \"v3\").",
-                    "[9:25] The expression is involved in a cycle (\"v3\" -> \"v2\" -> \"v1\").",
+                    "[9:25] The referenced declaration with name \"v3\" is not valid.",
                 },
             DisplayName = "resolved variable cycle should not hang")]
         [DataRow(@"

src/Bicep.Core/Analyzers/Linter/Rules/UseStableResourceIdentifiersRule.cs

@@ -74,6 +74,9 @@ public override void VisitVariableAccessSyntax(VariableAccessSyntax syntax)
             {
                 switch (model.GetSymbolInfo(syntax))
                 {
+                    case Symbol symbol when pathSegments.Contains(symbol):
+                        // Symbol cycles are reported on elsewhere. As far as this visitor is concerned, a cycle does not introduce nondeterminism.
+                        break;
                     case ParameterSymbol @parameter:
                         if (@parameter.DeclaringParameter.Modifier is ParameterDefaultValueSyntax defaultValueSyntax)
                         {
@@ -83,12 +86,6 @@ public override void VisitVariableAccessSyntax(VariableAccessSyntax syntax)
                         }
                         break;
                     case VariableSymbol @variable:
-                        // Variable cycles are reported on elsewhere. As far as this visitor is concerned, a cycle does not introduce nondeterminism.
-                        if (pathSegments.Contains(@variable))
-                        {
-                            return;
-                        }
-
                         pathSegments.AddLast(@variable);
                         @variable.DeclaringVariable.Value.Accept(this);
                         pathSegments.RemoveLast();

src/Bicep.Core/TypeSystem/TypeAssignmentVisitor.cs

@@ -111,6 +111,13 @@ private void AssignTypeWithDiagnostics(SyntaxBase syntax, Func<IDiagnosticWriter
             if (this.binder.TryGetCycle(declaredSymbol) is { } cycle)
             {
                 // there's a cycle. stop visiting now or we never will!
+
+                if (!cycle.Any(symbol => this.binder.IsDescendant(syntax, symbol.DeclaringSyntax)))
+                {
+                    // the supplied syntax is not part of the cycle, just a reference to the cyclic symbol.
+                    return ErrorType.Create(DiagnosticBuilder.ForPosition(syntax).ReferencedSymbolHasErrors(declaredSymbol.Name));
+                }
+
                 if (cycle.Length == 1)
                 {
                     return ErrorType.Create(DiagnosticBuilder.ForPosition(syntax).CyclicExpressionSelfReference());