faysilalshareef/code-analysis

Code Analysis — Roslyn Analyzers & EditorConfig

Core Principles

• Roslyn analyzers catch issues at compile time
• .editorconfig enforces consistent code style across the team
• Directory.Build.props enables analyzers for all projects
• TreatWarningsAsErrors in CI prevents degradation
• StyleCop.Analyzers for naming and formatting rules
• EnforceCodeStyleInBuild enables style warnings during build

Key Patterns

EditorConfig

# .editorconfig (solution root)
root = true

[*]
indent_style = space
indent_size = 4
end_of_line = crlf
charset = utf-8-bom
trim_trailing_whitespace = true
insert_final_newline = true

[*.cs]
# Namespace
csharp_style_namespace_declarations = file_scoped:warning

# Using directives
dotnet_sort_system_directives_first = true
csharp_using_directive_placement = outside_namespace:warning

# var preferences
csharp_style_var_for_built_in_types = true:suggestion
csharp_style_var_when_type_is_apparent = true:suggestion
csharp_style_var_elsewhere = true:suggestion

# Expression-bodied members
csharp_style_expression_bodied_methods = when_on_single_line:suggestion
csharp_style_expression_bodied_properties = true:suggestion

# Null checking
dotnet_style_prefer_is_null_check_over_reference_equality_method = true:warning

# Naming conventions
dotnet_naming_rule.private_fields.symbols = private_fields
dotnet_naming_rule.private_fields.style = _camelCase
dotnet_naming_rule.private_fields.severity = warning

dotnet_naming_symbols.private_fields.applicable_kinds = field
dotnet_naming_symbols.private_fields.applicable_accessibilities = private

dotnet_naming_style._camelCase.required_prefix = _
dotnet_naming_style._camelCase.capitalization = camel_case

# Analyzer severity
dotnet_diagnostic.CA1062.severity = warning  # Validate arguments
dotnet_diagnostic.CA1822.severity = suggestion  # Mark static
dotnet_diagnostic.CA2007.severity = none  # ConfigureAwait

Directory.Build.props Analyzer Configuration

<Project>
  <PropertyGroup>
    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
    <AnalysisLevel>latest-recommended</AnalysisLevel>
    <EnableNETAnalyzers>true</EnableNETAnalyzers>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.556">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Meziantou.Analyzer" Version="2.0.182">
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
  </ItemGroup>
</Project>

StyleCop Configuration

// stylecop.json (solution root)
{
  "$schema": "https://raw.githubusercontent.com/DotNetAnalyzers/StyleCopAnalyzers/master/StyleCop.Analyzers/StyleCop.Analyzers/Settings/stylecop.schema.json",
  "settings": {
    "documentationRules": {
      "companyName": "{Company}",
      "xmlHeader": false,
      "documentInterfaces": false,
      "documentPrivateElements": false
    },
    "orderingRules": {
      "usingDirectivesPlacement": "outsideNamespace"
    }
  }
}

Suppressing False Positives

// Targeted suppression (prefer over global)
[SuppressMessage("Style", "IDE0057",
    Justification = "Range operator less readable here")]
public string GetPrefix(string value) => value.Substring(0, 3);

// Global suppression file
// GlobalSuppressions.cs
[assembly: SuppressMessage("Design", "CA1062",
    Scope = "namespaceanddescendants",
    Target = "~N:{Company}.{Domain}.Tests")]

Anti-Patterns

| Anti-Pattern | Correct Approach | |---|---| | Disabling all warnings | Fix warnings or suppress with justification | | No .editorconfig | Create one at solution root | | Analyzers only in CI | Enable in IDE and build | | Global suppressions without justification | Always include Justification |

Detect Existing Patterns

# Find .editorconfig
find . -name ".editorconfig" -type f

# Find analyzer packages
grep -r "StyleCop\|Meziantou\|Roslynator" --include="*.csproj" .
grep -r "StyleCop\|Meziantou\|Roslynator" --include="*.props" .

# Find TreatWarningsAsErrors
grep -r "TreatWarningsAsErrors" --include="*.props" --include="*.csproj" .

Adding to Existing Project

1. Check for existing .editorconfig — extend, don't replace
2. Match existing analyzer configuration in Directory.Build.props
3. Don't enable TreatWarningsAsErrors without fixing existing warnings
4. Add analyzers gradually — start with recommended level
5. Run dotnet format to auto-fix formatting issues