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Configuration files for code analysis rules

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Code analysis rules have various configuration options. You specify these options as key-value pairs in one of the following analyzer configuration files:

  • EditorConfig file: File-based or folder-based configuration options.
  • Global AnalyzerConfig file: Project-level configuration options. Useful when some project files reside outside the project folder.

Tip

You can also set code analysis configuration properties in your project file. These properties configure code analysis at the bulk level, from completely turning code analysis on or off down to category-level rule configuration. For more information, see EnableNETAnalyzers, AnalysisLevel, AnalysisLevel<Category>, and AnalysisMode.

EditorConfig

EditorConfig files are used to provide options that apply to specific source files or folders. Options are placed under section headers to identify the applicable files and folders. Add an entry for each rule you want to configure, and place it under the corresponding file extension section, for example, [*.cs].

[*.cs]
<option_name> = <option_value>

In the above example, [*.cs] is an editorconfig section header to select all C# files with .cs file extension within the current folder, including subfolders. The subsequent entry, <option_name> = <option_value>, is an analyzer option that will be applied to all the C# files.

You can apply EditorConfig file conventions to a folder, a project, or an entire repo by placing the file in the corresponding directory. These options are applied when executing the analysis at build time and while you edit code in Visual Studio.

Note

EditorConfig options apply only to source files in a project or directory. Files that are included in a project as AdditionalFiles aren't considered source files, and EditorConfig options aren't applied to these files. To apply a rule option to non-source files, specify the option in a global configuration file.

If you have an existing .editorconfig file for editor settings such as indent size or whether to trim trailing whitespace, you can place your code analysis configuration options in the same file.

Tip

Visual Studio provides an .editorconfig item template that makes it easy to add one of these files to your project. For more information, see Add an EditorConfig file to a project.

Example

Following is an example EditorConfig file to configure options and rule severity:

# Remove the line below if you want to inherit .editorconfig settings from higher directories
root = true

# C# files
[*.cs]

#### Core EditorConfig Options ####

# Indentation and spacing
indent_size = 4
indent_style = space
tab_width = 4

#### .NET Coding Conventions ####

# this. and Me. preferences
dotnet_style_qualification_for_method = true

#### Diagnostic configuration ####

# CA1000: Do not declare static members on generic types
dotnet_diagnostic.CA1000.severity = warning

Global AnalyzerConfig

You can also configure analyzer options with global AnalyzerConfig files. These files are used to provide options that apply to all the source files in a project, regardless of their file names or file paths.

Unlike EditorConfig files, global configuration files can't be used to configure editor style settings for IDEs, such as indent size or whether to trim trailing whitespace. Instead, they're designed purely for specifying project-level analyzer configuration options.

Format

Unlike EditorConfig files, which must have section headers, such as [*.cs], to identify the applicable files and folders, global AnalyzerConfig files don't have section headers. Instead, they require a top level entry of the form is_global = true to differentiate them from regular EditorConfig files. This indicates that all the options in the file apply to the entire project. For example:

is_global = true
<option_name> = <option_value>

Naming

Unlike EditorConfig files, which must be named .editorconfig, global config files don't need to have a specific name or extension. However, if you name these files as .globalconfig, then they're implicitly applied to all the C# and Visual Basic projects within the current folder, including subfolders. Otherwise, you must explicitly add the GlobalAnalyzerConfigFiles item to your MSBuild project file:

<ItemGroup>
  <GlobalAnalyzerConfigFiles Include="<path_to_global_analyzer_config>" />
</ItemGroup>

Consider the following naming recommendations:

  • End users should name their global configuration files .globalconfig.
  • NuGet package creators should name their global config files <%Package_Name%>.globalconfig.
  • MSBuild tooling-generated global config files should be named <%Target_Name%>_Generated.globalconfig or similar.

Note

The top-level entry is_global = true is not required when the file is named .globalconfig, but it's recommended for clarity.

Conditional inclusion

You can use a global configuration file to disable or enable certain code analysis rules in different environments. For example, you might want to disable some code analysis rules for unit test projects. To do that, you could set the severity for the applicable rules to none in the configuration file, for example:

# CA1861: Prefer 'static readonly' fields over constant array arguments
dotnet_diagnostic.CA1861.severity = none

You can then customize your build to only include the configuration file in test projects based on conditions specific to your build. For example:

<ItemGroup Condition="'$(IsShipping)' == 'false'">
  <!-- Include CodeAnalysis.test.globalconfig to override (relax) some rules from the primary configuration. -->
  <GlobalAnalyzerConfigFiles Include="$(MSBuildThisFileDirectory)CodeAnalysis.test.globalconfig" />
</ItemGroup>

Distribution in NuGet packages

Global AnalyzerConfig files can be distributed with NuGet packages. To do so, add a .props file to the NuGet package. In the .props file, add a GlobalAnalyzerConfigFiles item under the Project node:

<Project>
  <ItemGroup>
    <GlobalAnalyzerConfigFiles Include="Relative/Path/to/PackageName.globalconfig" />
  </ItemGroup>
</Project>

Example

Following is an example global AnalyzerConfig file to configure options and rule severity at the project level:

# Top level entry required to mark this as a global AnalyzerConfig file
is_global = true

# NOTE: No section headers for configuration entries

#### .NET Coding Conventions ####

# this. and Me. preferences
dotnet_style_qualification_for_method = true:warning

#### Diagnostic configuration ####

# CA1000: Do not declare static members on generic types
dotnet_diagnostic.CA1000.severity = warning

Precedence

Both EditorConfig files and global AnalyzerConfig files specify a key-value pair for each option. Conflicts arise when there are multiple entries with the same key but different values. The following precedence rules are used to resolve conflicts.

Conflicting entry locations Precedence rule
In the same configuration file The entry that appears later in the file wins. This is true for conflicting entries within a single EditorConfig file and also within a single global AnalyzerConfig file.
In two EditorConfig files The entry in the EditorConfig file that's deeper in the file system, and hence has a longer file path, wins.
In two global AnalyzerConfig files .NET 5: A compiler warning is reported and both entries are ignored.
.NET 6 and later versions: The entry from the file with a higher value for global_level takes precedence. If global_level isn't explicitly defined and the file is named .globalconfig, the global_level value defaults to 100; for all other global AnalyzerConfig files, global_level defaults to 0. If the global_level values for the configuration files with conflicting entries are equal, a compiler warning is reported and both entries are ignored.
In an EditorConfig file and a Global AnalyzerConfig file The entry in the EditorConfig file wins.

Severity options

For severity configuration options, the following additional precedence rules apply:

  • Severity options specified at the command line as compiler options (-nowarn or -warnaserror) always override severity configuration options specified in EditorConfig and global AnalyzerConfig files.

  • The precedence rules for conflicting severity entries from a ruleset file and an EditorConfig or global AnalyzerConfig file is undefined.

    Ruleset files are deprecated in favor of EditorConfig and global AnalyzerConfig files. We recommend that you convert ruleset files to an equivalent EditorConfig file.

  • For information about precedence rules for related severity options with different keys, for example, when different severities are specified for a single rule and for the category that rule falls under, see Configuration options for code analysis.

See also