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Check Unused Code

Checks unused classes, fields, properties, methods, functions, variables, extensions, enums, mixins and type aliases.

To execute the command, run:

$ dcm check-unused-code lib # or dcm uc lib

Full command description:

Usage: dcm check-unused-code [arguments] <directories>
-h, --help                                       Print this usage information.


    --no-exclude-overridden                      Do not treat overridden members as always used.


-r, --reporter=<console>                         Analysis output format.
                                                 [console (default), json, codeclimate, gitlab, checkstyle]
-a, --absolute-path                              Show absolute paths in console reporter output.
    --json-path=<path/to/file.json>              Path to the JSON file with the analysis output.


-c, --print-config                               Print resolved config.


    --root-folder=<./>                           Root folder.
                                                 (defaults to the current directory)
    --sdk-path=<directory-path>                  Dart SDK directory path.
                                                 If the project has a `.fvm/flutter_sdk` symlink, it will be used if the SDK is not found.
    --exclude=<{**/*.g.dart,**/*.freezed.dart}>  File paths in Glob syntax to be exclude.
                                                 (defaults to "{**/*.g.dart,**/*.freezed.dart}")


    --no-congratulate                            Don't show output even when there are no issues.


    --verbose                                    Show verbose logs.


    --ci-key                                     The license key to run on CI server. Can be provided via DCM_CI_KEY env variable.
    --email                                      The email used to purchase the license. Can be provided via DCM_EMAIL env variable.


    --no-analytics                               Disable sending anonymous usage statistics.


    --monorepo                                   Include publicly exported code into the check.


    --[no-]fatal-unused                          Treat find unused code as fatal.
                                                 (defaults to on)

Suppressing the command​

In order to suppress the command add the ignore: unused-code comment. To suppress for an entire file add ignore_for_file: unused-code to the beginning of a file.

You can also set unused-code-exclude: config entry in the analysis_options.yaml (this configuration is used by both CLI and the IDE integration).

Monorepo support​

warning

By default, this command treats all code that is exported from the package as used. It uses check-exports-completeness results and won't report even transitive public entities that are not exported directly.

This command also follows this convention of locating implementation files in the lib/src/ folder. If you don't follow this convention, you will need to pass the --monorepo flag for this command to work.

To disable this behavior use --monorepo flag. This might be useful when all the packages in your repository are only used within the repository and are not published to the pub.

Including class member hierarchies into the analysis​

By default, this command does not analyze overridden members as they can be used implicitly through the parent class.

To include overridden members into the analysis pass the --no-exclude-overridden flag.

warning

This mode is experimental and may have false positives. If you encounter any issues, please post them on our Discord.

info

This mode won't analyze external code (from pub or flutter) or code that extends external code.

Output example​

Console​

Use --reporter=console to enable this format.

Console

JSON​

The reporter prints a single JSON object containing meta information and the unused code file paths. Use --reporter=json to enable this format.

The root object fields are​

  • formatVersion - an integer representing the format version (will be incremented each time the serialization format changes)
  • timestamp - a creation time of the report in YYYY-MM-DD HH:MM:SS format
  • unusedCode - an array of unused code issues
{
  "formatVersion": 2,
  "timestamp": "2021-04-11 14:44:42",
  "unusedCode": [
    {
      ...
    },
    {
      ...
    },
    {
      ...
    }
  ]
}

The unusedCode object fields are​

  • path - a relative path of the unused file
  • issues - an array of issues detected in the target file
{
  "path": "lib/src/some/file.dart",
  "issues": [
    ...
  ],
}

The issue object fields are​

  • declarationType - unused declaration type
  • declarationName - unused declaration name
  • offset - a zero-based offset of the class member location in the source
  • line - a zero-based line of the class member location in the source
  • column - a zero-based column of class member the location in the source
{
  "declarationType": "extension",
  "declarationName": "StringX",
  "offset": 156,
  "line": 7,
  "column": 1
}

GitLab​

Reports unused code issues in merge requests based on Code Quality custom tool. Use --reporter=gitlab to enable this format.

Checkstyle​

Use --reporter=checkstyle to enable this format.

<?xml version="1.0"?>
<checkstyle version="10.0">
  <file name="example.dart">
    <error line="5" column="3" severity="warning" message="Unused class SomeClass" source="unused-code-issue"/>
  </file>
</checkstyle>