public override void Initialize(AnalysisContext analysisContext)
{
analysisContext.EnableConcurrentExecution();
analysisContext.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
analysisContext.RegisterCompilationAction(compilationContext =>
{
if (compilationContext.Compilation.SyntaxTrees.FirstOrDefault() is not SyntaxTree tree)
{
return;
}
// Try read the additional file containing the code metrics configuration.
if (!TryGetRuleIdToThresholdMap(
compilationContext.Options.AdditionalFiles,
compilationContext.CancellationToken,
out AdditionalText? additionalTextOpt,
out ImmutableDictionary <string, IReadOnlyList <(SymbolKind?, uint)> >?ruleIdToThresholdMap,
out List <Diagnostic>?invalidFileDiagnostics) &&
invalidFileDiagnostics != null)
{
// Report any invalid additional file diagnostics.
foreach (var diagnostic in invalidFileDiagnostics)
{
compilationContext.ReportDiagnostic(diagnostic);
}
return;
}
// Compute code metrics.
// For the calculation of the inheritance tree, we are allowing specific exclusions:
// - all types from System namespaces
// - all types/namespaces provided by the user
// so that the calculation isn't unfair.
// For example inheriting from WPF/WinForms UserControl makes your class over the default threshold, yet there isn't anything you can do about it.
var inheritanceExcludedTypes = compilationContext.Options.GetInheritanceExcludedSymbolNamesOption(CA1501Rule, tree, compilationContext.Compilation,
defaultForcedValue: "N:System.*", compilationContext.CancellationToken);
var metricsAnalysisContext = new CodeMetricsAnalysisContext(compilationContext.Compilation, compilationContext.CancellationToken,
namedType => inheritanceExcludedTypes.Contains(namedType));
var computeTask = CodeAnalysisMetricData.ComputeAsync(metricsAnalysisContext);
computeTask.Wait(compilationContext.CancellationToken);
// Analyze code metrics tree and report diagnostics.
analyzeMetricsData(computeTask.Result);
void analyzeMetricsData(CodeAnalysisMetricData codeAnalysisMetricData)
{
var symbol = codeAnalysisMetricData.Symbol;
// CA1501: Avoid excessive inheritance
if (symbol.Kind == SymbolKind.NamedType && codeAnalysisMetricData.DepthOfInheritance.HasValue)
{
uint?inheritanceThreshold = getThreshold(CA1501RuleId, symbol.Kind);
if (inheritanceThreshold.HasValue && codeAnalysisMetricData.DepthOfInheritance.Value > inheritanceThreshold.Value)
{
// '{0}' has an object hierarchy '{1}' levels deep within the defining module. If possible, eliminate base classes within the hierarchy to decrease its hierarchy level below '{2}': '{3}'
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.DepthOfInheritance;
var arg3 = inheritanceThreshold + 1;
var arg4 = string.Join(", ", ((INamedTypeSymbol)symbol).GetBaseTypes(t => !inheritanceExcludedTypes.Contains(t)).Select(t => t.Name));
var diagnostic = symbol.CreateDiagnostic(CA1501Rule, arg1, arg2, arg3, arg4);
compilationContext.ReportDiagnostic(diagnostic);
}
}
// CA1502: Avoid excessive complexity
uint?complexityThreshold = getThreshold(CA1502RuleId, symbol.Kind);
if (complexityThreshold.HasValue && codeAnalysisMetricData.CyclomaticComplexity > complexityThreshold.Value)
{
// '{0}' has a cyclomatic complexity of '{1}'. Rewrite or refactor the code to decrease its complexity below '{2}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.CyclomaticComplexity;
var arg3 = complexityThreshold.Value + 1;
var diagnostic = symbol.CreateDiagnostic(CA1502Rule, arg1, arg2, arg3);
compilationContext.ReportDiagnostic(diagnostic);
}
// CA1505: Avoid unmaintainable code
uint?maintainabilityIndexThreshold = getThreshold(CA1505RuleId, symbol.Kind);
if (maintainabilityIndexThreshold.HasValue && maintainabilityIndexThreshold.Value > codeAnalysisMetricData.MaintainabilityIndex)
{
// '{0}' has a maintainability index of '{1}'. Rewrite or refactor the code to increase its maintainability index (MI) above '{2}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.MaintainabilityIndex;
var arg3 = maintainabilityIndexThreshold.Value - 1;
var diagnostic = symbol.CreateDiagnostic(CA1505Rule, arg1, arg2, arg3);
compilationContext.ReportDiagnostic(diagnostic);
}
// CA1506: Avoid excessive class coupling
uint?classCouplingThreshold = getThreshold(CA1506RuleId, symbol.Kind);
if (classCouplingThreshold.HasValue && codeAnalysisMetricData.CoupledNamedTypes.Count > classCouplingThreshold.Value)
{
// '{0}' is coupled with '{1}' different types from '{2}' different namespaces. Rewrite or refactor the code to decrease its class coupling below '{3}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.CoupledNamedTypes.Count;
var arg3 = GetDistinctContainingNamespacesCount(codeAnalysisMetricData.CoupledNamedTypes);
var arg4 = classCouplingThreshold.Value + 1;
var diagnostic = symbol.CreateDiagnostic(CA1506Rule, arg1, arg2, arg3, arg4);
compilationContext.ReportDiagnostic(diagnostic);
}
foreach (var child in codeAnalysisMetricData.Children)
{
analyzeMetricsData(child);
}
}
uint?getThreshold(string ruleId, SymbolKind symbolKind)
{
// Check if we have custom threshold value for the given ruleId and symbolKind.
if (ruleIdToThresholdMap != null &&
ruleIdToThresholdMap.TryGetValue(ruleId, out IReadOnlyList <(SymbolKind?symbolKindOpt, uint threshold)> values))
{
foreach ((SymbolKind? symbolKindOpt, uint threshold) in values)
{
if (symbolKindOpt.HasValue && symbolKindOpt.Value == symbolKind)
{
return(threshold);
}
}
if (values.Count == 1 &&
values[0].symbolKindOpt == null &&
isApplicableByDefault(ruleId, symbolKind))
{
return(values[0].threshold);
}
}
return(getDefaultThreshold(ruleId, symbolKind));
}
static bool isApplicableByDefault(string ruleId, SymbolKind symbolKind)
{
switch (ruleId)
{
case CA1501RuleId:
return(symbolKind == SymbolKind.NamedType);
case CA1502RuleId:
return(symbolKind == SymbolKind.Method);
case CA1505RuleId:
switch (symbolKind)
{
case SymbolKind.NamedType:
case SymbolKind.Method:
case SymbolKind.Field:
case SymbolKind.Property:
case SymbolKind.Event:
return(true);
default:
return(false);
}
case CA1506RuleId:
switch (symbolKind)
{
case SymbolKind.NamedType:
case SymbolKind.Method:
case SymbolKind.Field:
case SymbolKind.Property:
case SymbolKind.Event:
return(true);
default:
return(false);
}
default:
throw new NotImplementedException();
}
}
public override void Initialize(AnalysisContext analysisContext)
{
analysisContext.EnableConcurrentExecution();
analysisContext.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
analysisContext.RegisterCompilationAction(compilationContext =>
{
if (compilationContext.Compilation.SyntaxTrees.FirstOrDefault() is not SyntaxTree tree)
{
return;
}
// Try read the additional file containing the code metrics configuration.
if (!TryGetRuleIdToThresholdMap(
compilationContext.Options.AdditionalFiles,
compilationContext.CancellationToken,
out AdditionalText? additionalTextOpt,
out ImmutableDictionary <string, IReadOnlyList <(SymbolKind?, uint)> >?ruleIdToThresholdMap,
out List <Diagnostic>?invalidFileDiagnostics) &&
invalidFileDiagnostics != null)
{
// Report any invalid additional file diagnostics.
foreach (var diagnostic in invalidFileDiagnostics)
{
compilationContext.ReportDiagnostic(diagnostic);
}
return;
}
var metricsAnalysisContext = new CodeMetricsAnalysisContext(compilationContext.Compilation, compilationContext.CancellationToken,
namedType => IsConfiguredToSkipFromInheritanceCount(namedType, compilationContext, tree));
var computeTask = CodeAnalysisMetricData.ComputeAsync(metricsAnalysisContext);
computeTask.Wait(compilationContext.CancellationToken);
// Analyze code metrics tree and report diagnostics.
analyzeMetricsData(computeTask.Result);
void analyzeMetricsData(CodeAnalysisMetricData codeAnalysisMetricData)
{
var symbol = codeAnalysisMetricData.Symbol;
// CA1501: Avoid excessive inheritance
if (symbol.Kind == SymbolKind.NamedType && codeAnalysisMetricData.DepthOfInheritance.HasValue)
{
uint?inheritanceThreshold = getThreshold(CA1501RuleId, symbol.Kind);
if (inheritanceThreshold.HasValue && codeAnalysisMetricData.DepthOfInheritance.Value > inheritanceThreshold.Value)
{
// '{0}' has an object hierarchy '{1}' levels deep within the defining module. If possible, eliminate base classes within the hierarchy to decrease its hierarchy level below '{2}': '{3}'
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.DepthOfInheritance;
var arg3 = inheritanceThreshold + 1;
var arg4 = string.Join(", ", ((INamedTypeSymbol)symbol).GetBaseTypes(t => !IsConfiguredToSkipFromInheritanceCount(t, compilationContext, tree)).Select(t => t.Name));
var diagnostic = symbol.CreateDiagnostic(CA1501Rule, arg1, arg2, arg3, arg4);
compilationContext.ReportDiagnostic(diagnostic);
}
}
// CA1502: Avoid excessive complexity
uint?complexityThreshold = getThreshold(CA1502RuleId, symbol.Kind);
if (complexityThreshold.HasValue && codeAnalysisMetricData.CyclomaticComplexity > complexityThreshold.Value)
{
// '{0}' has a cyclomatic complexity of '{1}'. Rewrite or refactor the code to decrease its complexity below '{2}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.CyclomaticComplexity;
var arg3 = complexityThreshold.Value + 1;
var diagnostic = symbol.CreateDiagnostic(CA1502Rule, arg1, arg2, arg3);
compilationContext.ReportDiagnostic(diagnostic);
}
// CA1505: Avoid unmaintainable code
uint?maintainabilityIndexThreshold = getThreshold(CA1505RuleId, symbol.Kind);
if (maintainabilityIndexThreshold.HasValue && maintainabilityIndexThreshold.Value > codeAnalysisMetricData.MaintainabilityIndex)
{
// '{0}' has a maintainability index of '{1}'. Rewrite or refactor the code to increase its maintainability index (MI) above '{2}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.MaintainabilityIndex;
var arg3 = maintainabilityIndexThreshold.Value - 1;
var diagnostic = symbol.CreateDiagnostic(CA1505Rule, arg1, arg2, arg3);
compilationContext.ReportDiagnostic(diagnostic);
}
// CA1506: Avoid excessive class coupling
uint?classCouplingThreshold = getThreshold(CA1506RuleId, symbol.Kind);
if (classCouplingThreshold.HasValue && codeAnalysisMetricData.CoupledNamedTypes.Count > classCouplingThreshold.Value)
{
// '{0}' is coupled with '{1}' different types from '{2}' different namespaces. Rewrite or refactor the code to decrease its class coupling below '{3}'.
var arg1 = symbol.Name;
var arg2 = codeAnalysisMetricData.CoupledNamedTypes.Count;
var arg3 = GetDistinctContainingNamespacesCount(codeAnalysisMetricData.CoupledNamedTypes);
var arg4 = classCouplingThreshold.Value + 1;
var diagnostic = symbol.CreateDiagnostic(CA1506Rule, arg1, arg2, arg3, arg4);
compilationContext.ReportDiagnostic(diagnostic);
}
foreach (var child in codeAnalysisMetricData.Children)
{
analyzeMetricsData(child);
}
}
uint?getThreshold(string ruleId, SymbolKind symbolKind)
{
// Check if we have custom threshold value for the given ruleId and symbolKind.
if (ruleIdToThresholdMap != null &&
ruleIdToThresholdMap.TryGetValue(ruleId, out IReadOnlyList <(SymbolKind?symbolKindOpt, uint threshold)> values))
{
foreach ((SymbolKind? symbolKindOpt, uint threshold) in values)
{
if (symbolKindOpt.HasValue && symbolKindOpt.Value == symbolKind)
{
return(threshold);
}
}
if (values.Count == 1 &&
values[0].symbolKindOpt == null &&
isApplicableByDefault(ruleId, symbolKind))
{
return(values[0].threshold);
}
}
return(getDefaultThreshold(ruleId, symbolKind));
}
static bool isApplicableByDefault(string ruleId, SymbolKind symbolKind)
{
return(ruleId switch
{
CA1501RuleId => symbolKind == SymbolKind.NamedType,
CA1502RuleId => symbolKind == SymbolKind.Method,
CA1505RuleId => symbolKind switch
{
SymbolKind.NamedType or SymbolKind.Method or SymbolKind.Field or SymbolKind.Property or SymbolKind.Event => true,
_ => false,
},
CA1506RuleId => symbolKind switch
{
SymbolKind.NamedType or SymbolKind.Method or SymbolKind.Field or SymbolKind.Property or SymbolKind.Event => true,
_ => false,
},
