Check Unused Code
Reports unused declarations (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.
--exclude-public-api (--ep) Exclude publicly exported code from the analysis output.
--no-exclude-overridden Include overridden members into the unused code and parameters analysis.
-r, --reporter="console" (--output-format) Analysis output format.
[console (default), json, codeclimate, gitlab, checkstyle, sonar]
-a, --absolute-path Show absolute paths in console reporter output.
--output-to="path/to/file" Path to the file with the analysis output.
-c, --print-config Print resolved config.
--root-folder="./" Root folder.
(defaults to the current directory)
-s, --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.
-e, --exclude="{**/*.g.dart,**/*.freezed.dart}" Files to exclude (in Glob syntax).
(defaults to "{**/*.g.dart,**/*.freezed.dart}")
--root-exclude Files to exclude, relative to the root folder (in Glob syntax).
--[no-]congratulate 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.
--[no-]fatal-unused Treat unused code as fatal.
(defaults to on)
Suppressing the Command​
To suppress issues produced by the command, add the ignore: unused-code comment. To suppress the command for an entire file, add the ignore_for_file: unused-code comment to the beginning of a file.
You can also set the exclude:unused-code: config entry in the analysis_options.yaml (this configuration is used by both CLI and the IDE integration).
Excluding Public API​
By default, this command analyzes all code, even if it's part a package's public API.
To exclude such code from the analysis, pass the exclude-public-api CLI flag.
This command follows this convention when locating API and implementation files.
Overriding "exclude-public-api" for a Particular Package​
To override the exclude-public-api flag for a particular package, set the exclude-public-api entry in the analysis_options.yaml.
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.
This mode won't analyze external code (from pub or flutter) or code that extends external code.
Output Example​
Console (default)​
Use --reporter=console to get output in console format.
JSON​
Use --reporter=json to get output as a single JSON object containing metadata and the list of unused code issues.
Format specification
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 formatunusedCodeResults- an array of objectssummary- an array of objects
{
"formatVersion": 10,
"timestamp": "2021-04-11 14:44:42",
"unusedCodeResults": [
{
...
},
{
...
},
{
...
}
],
"summary": [
{
...
},
{
...
}
]
}
The result object fields are​
path- the relative path to the file with issuesissues- an array of issues detected in the target file
{
"path": "lib/src/some/file.dart",
"issues": [
...
],
}
The issue object fields are​
id- issue idmessage- the message associated with the issuelocation- the location associated with the issueeffortInMinutes- an estimated effort to fix the issue (in minutes)declarationName- unused declaration namedeclarationType- unused declaration typeusedOnlyInTestsa boolean value indicating the code is only used in test files
{
"id": "unused-code-issue",
"message": "Unused getter latoBlack",
"location": {
...
},
"effortInMinutes": 10,
"declarationName": "latoBlack",
"declarationType": "getter",
"usedOnlyInTests": false
}
The location object fields are​
startColumn- the start column of the entitystartLine- the start line of the entityendColumn- the end column of the entityendLine- the end line of the entitystartOffset- the offset of the entity
{
"endColumn": 2,
"endLine": 90,
"startColumn": 1,
"startLine": 48,
"startOffset": 1638
}
The summary-record object fields are​
title- a message with the summary entry titlevalue- the actual value of the entry
{
"title": "Total unused code declarations",
"value": 1
}
Old format specification (prior to DCM 1.26.0)
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 formatunusedCode- 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 fileissues- an array of issues detected in the target file
{
"path": "lib/src/some/file.dart",
"issues": [
...
],
}
The issue object fields are​
declarationType- unused declaration typedeclarationName- unused declaration nameoffset- a zero-based offset of the class member location in the sourceline- a zero-based line of the class member location in the sourcecolumn- a zero-based column of class member the location in the sourceusedOnlyInTestsa boolean value indicating the code is only used in test files
{
"declarationType": "extension",
"declarationName": "StringX",
"offset": 156,
"line": 7,
"column": 1,
"usedOnlyInTests": false
}
GitLab​
Use --reporter=gitlab to get output in a GitLab-compatible format. To learn how to integrate DCM with GitLab, refer to this guide.
Code Climate​
Use --reporter=codeclimate to get output in Code Climate format.
Output example
{"type":"issue","check_name":"unused-code-issue","description":"Unused field buttonRect","categories":["Bug Risk"],"location":{"path":"lib/src/buttons/pulldown_button.dart","positions":{"begin":{"column":3,"line":41},"end":{"column":25,"line":41}}},"severity":"major","fingerprint":"46ed0a539d46e514e67003f0a661976e"}
{"type":"issue","check_name":"unused-code-issue","description":"Unused field constraints","categories":["Bug Risk"],"location":{"path":"lib/src/buttons/pulldown_button.dart","positions":{"begin":{"column":3,"line":42},"end":{"column":36,"line":42}}},"severity":"major","fingerprint":"a9a5952f5de9e4c94a4c638d2410c7a4"}
Checkstyle​
Use --reporter=checkstyle to get output in Checkstyle format.
Output example
<?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>
Checkstyle format is supported by Bitbucket. To learn how to integrate DCM with Bitbucket, refer to this guide.
Sonar​
Use --reporter=sonar to get output in SonarQube's generic format for external issues.
Output example
{
"rules": [
{
"cleanCodeAttribute": "CLEAR",
"description": "To learn more, visit the documentation https://dcm.dev/docs/cli/code-quality-checks/unused-code/",
"engineId": "dcm",
"id": "unused-code-issue",
"impacts": [
{
"severity": "MEDIUM",
"softwareQuality": "MAINTAINABILITY"
}
],
"name": "unused-code-issue"
}
],
"issues": [
{
"effortMinutes": 10,
"primaryLocation": {
"filePath": "lib/src/home_i18n.dart",
"message": "Unused getter homeTab",
"textRange": {
"endColumn": 9,
"endLine": 14,
"startColumn": 3,
"startLine": 10
}
},
"ruleId": "unused-code-issue"
},
{
"effortMinutes": 10,
"primaryLocation": {
"filePath": "lib/src/home_i18n.dart",
"message": "Unused getter profileTab",
"textRange": {
"endColumn": 9,
"endLine": 20,
"startColumn": 3,
"startLine": 16
}
},
"ruleId": "unused-code-issue"
}
]
}