New Rule0087: Use IsNullGuid (#882)

BusinessCentral.LinterCop.Test/Rule0087.cs

@@ -0,0 +1,35 @@
+namespace BusinessCentral.LinterCop.Test;
+
+public class Rule0087
+{
+    private string _testCaseDir = "";
+
+    [SetUp]
+    public void Setup()
+    {
+        _testCaseDir = Path.Combine(Directory.GetParent(Environment.CurrentDirectory)!.Parent!.Parent!.FullName,
+            "TestCases", "Rule0087");
+    }
+
+    [Test]
+    [TestCase("EmptyStringLiteral")]
+    public async Task HasDiagnostic(string testCase)
+    {
+        var code = await File.ReadAllTextAsync(Path.Combine(_testCaseDir, "HasDiagnostic", $"{testCase}.al"))
+            .ConfigureAwait(false);
+
+        var fixture = RoslynFixtureFactory.Create<Rule0087UseIsNullGuid>();
+        fixture.HasDiagnostic(code, DiagnosticDescriptors.Rule0087UseIsNullGuid.Id);
+    }
+
+    [Test]
+    [TestCase("EmptyStringLiteral")]
+    public async Task NoDiagnostic(string testCase)
+    {
+        var code = await File.ReadAllTextAsync(Path.Combine(_testCaseDir, "NoDiagnostic", $"{testCase}.al"))
+            .ConfigureAwait(false);
+
+        var fixture = RoslynFixtureFactory.Create<Rule0087UseIsNullGuid>();
+        fixture.NoDiagnosticAtMarker(code, DiagnosticDescriptors.Rule0087UseIsNullGuid.Id);
+    }
+}

BusinessCentral.LinterCop.Test/TestCases/Rule0087/HasDiagnostic/EmptyStringLiteral.al

@@ -0,0 +1,9 @@
+codeunit 50100 MyCodeunit
+{
+    procedure MyProcedure()
+    var
+        MyGuid: Guid;
+    begin
+        if MyGuid = [|''|] then;
+    end;
+}

BusinessCentral.LinterCop.Test/TestCases/Rule0087/NoDiagnostic/EmptyStringLiteral.al

@@ -0,0 +1,9 @@
+codeunit 50100 MyCodeunit
+{
+    procedure MyProcedure()
+    var
+        MyGuid: Guid;
+    begin
+        MyGuid := [|''|];
+    end;
+}

BusinessCentral.LinterCop/Design/Rule0087UseIsNullGuid.cs

@@ -0,0 +1,76 @@
+using BusinessCentral.LinterCop.Helpers;
+using Microsoft.Dynamics.Nav.CodeAnalysis;
+using Microsoft.Dynamics.Nav.CodeAnalysis.Diagnostics;
+using Microsoft.Dynamics.Nav.CodeAnalysis.Symbols;
+using Microsoft.Dynamics.Nav.CodeAnalysis.Utilities;
+using System.Collections.Immutable;
+
+namespace BusinessCentral.LinterCop.Design;
+
+[DiagnosticAnalyzer]
+public class Rule0087UseIsNullGuid : DiagnosticAnalyzer
+{
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } =
+        ImmutableArray.Create(DiagnosticDescriptors.Rule0087UseIsNullGuid);
+
+    public override void Initialize(AnalysisContext context) =>
+        context.RegisterOperationAction(new Action<OperationAnalysisContext>(this.AnalyzeEqualsStatement), OperationKind.BinaryOperatorExpression);
+
+    private void AnalyzeEqualsStatement(OperationAnalysisContext ctx)
+    {
+        if (ctx.IsObsoletePendingOrRemoved() || ctx.Operation is not IBinaryOperatorExpression operation)
+            return;
+
+        // Validate the left operand is a Guid type
+        if (!IsNavTypeKindGuid(operation.LeftOperand))
+            return;
+
+        // Validate the right operand is an empty string literal
+        if (IsEmptyStringLiteral(operation.RightOperand))
+        {
+            ctx.ReportDiagnostic(Diagnostic.Create(
+                DiagnosticDescriptors.Rule0087UseIsNullGuid,
+                operation.RightOperand.Syntax.GetLocation(),
+                GetVariableName(operation.LeftOperand),
+                "''"));
+        }
+    }
+
+    private static bool IsNavTypeKindGuid(IOperation operand)
+    {
+        // Check for a conversion expression with a valid Guid type
+        if (operand.Kind == OperationKind.ConversionExpression &&
+            operand is IConversionExpression conversion &&
+            conversion.Operand is IOperation innerOperation)
+        {
+            return innerOperation.Type.GetNavTypeKindSafe() == NavTypeKind.Guid;
+        }
+
+        return false;
+    }
+
+    private static bool IsEmptyStringLiteral(IOperation operand)
+    {
+        // Ensure the operand is a literal expression of a string type
+        if (operand.Kind == OperationKind.LiteralExpression && operand.Type.IsTextType())
+        {
+            var constantValue = operand.ConstantValue.Value?.ToString();
+            return string.IsNullOrEmpty(constantValue);
+        }
+
+        return false;
+    }
+
+    private static string GetVariableName(IOperation operand)
+    {
+        // Extract the name of the Guid variable, or return an empty string if unavailable
+        if (operand.Kind == OperationKind.ConversionExpression &&
+            operand is IConversionExpression conversion &&
+            conversion.Operand is IOperation innerOperation)
+        {
+            return innerOperation.GetSymbol()?.Name.QuoteIdentifierIfNeeded() ?? string.Empty;
+        }
+
+        return string.Empty;
+    }
+}

BusinessCentral.LinterCop/LinterCop.ruleset.json

@@ -431,6 +431,11 @@
       "id": "LC0086",
       "action": "Info",
       "justification": "Use the new PageStyle datatype instead string literals."
+    },
+    {
+      "id": "LC0087",
+      "action": "Warning",
+      "justification": "Use IsNullGuid() to check for empty Guid values."
     }
   ]
 }

BusinessCentral.LinterCop/LinterCopAnalyzers.Generated.cs

@@ -884,4 +884,14 @@ public static class DiagnosticDescriptors
         isEnabledByDefault: true,
         description: LinterCopAnalyzers.GetLocalizableString("Rule0086PageStyleDataTypeDescription"),
         helpLinkUri: "https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0086");
+
+    public static readonly DiagnosticDescriptor Rule0087UseIsNullGuid = new(
+        id: LinterCopAnalyzers.AnalyzerPrefix + "0087",
+        title: LinterCopAnalyzers.GetLocalizableString("Rule0087UseIsNullGuidTitle"),
+        messageFormat: LinterCopAnalyzers.GetLocalizableString("Rule0087UseIsNullGuidFormat"),
+        category: "Design",
+        defaultSeverity: DiagnosticSeverity.Warning,
+        isEnabledByDefault: true,
+        description: LinterCopAnalyzers.GetLocalizableString("Rule0087UseIsNullGuidDescription"),
+        helpLinkUri: "https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0087");
 }

BusinessCentral.LinterCop/LinterCopAnalyzers.resx

@@ -894,4 +894,13 @@
   <data name="Rule0086PageStyleDataTypeDescription" xml:space="preserve">
     <value>Adopting the use of the new PageStyle datatype allows to more easily get the supported pagestyles via IntelliSense and avoids incorrect behaviour when a typo is made in hardcoded strings or label variables.</value>
   </data>
+  <data name="Rule0087UseIsNullGuidTitle" xml:space="preserve">
+    <value>Use IsNullGuid() to check for empty Guid values.</value>
+  </data>
+  <data name="Rule0087UseIsNullGuidFormat" xml:space="preserve">
+    <value>Use 'IsNullGuid({0})' method instead of comparing the Guid '{0}' with {1}, as this will result in a runtime error.</value>
+  </data>
+  <data name="Rule0087UseIsNullGuidDescription" xml:space="preserve">
+    <value>When checking if a Guid is empty, avoid using direct comparisons such as MyGuid = '', as this will result in a runtime error due to the invalid Guid format. Instead, use the IsNullGuid() method to perform the check safely and correctly.</value>
+  </data>
 </root>

README.md

@@ -239,4 +239,5 @@ For an example and the default values see: [LinterCop.ruleset.json](./BusinessCe
 |[LC0083](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0083)|Use new Date/Time/DateTime methods for extracting parts.|Info|
 |[LC0084](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0084)|Use return value for better error handling.|Info|
 |[LC0085](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0085)|Use the (CR)LFSeparator from the "Type Helper" codeunit.|Info|
-|[LC0086](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0086)|Use the new `PageStyle` datatype instead string literals.|Info|14.0|
+|[LC0086](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0086)|Use the new `PageStyle` datatype instead string literals.|Info|14.0|
+|[LC0087](https://github.com/StefanMaron/BusinessCentral.LinterCop/wiki/LC0087)|Use `IsNullGuid()` to check for empty Guid values.|Warning|