(#) Modifier factory functions should be extensions on Modifier !!! WARNING: Modifier factory functions should be extensions on Modifier This is a warning. Id : `ModifierFactoryExtensionFunction` Summary : Modifier factory functions should be extensions on Modifier Severity : Warning Category : Correctness Platform : Any Vendor : Jetpack Compose Identifier : androidx.compose.ui Feedback : https://issuetracker.google.com/issues/new?component=612128 Min : Lint 8.7+ Compiled : Lint 8.7+ Artifact : [androidx.compose.ui:ui-android](androidx_compose_ui_ui-android.md.html) Since : 1.5.0 Affects : Kotlin and Java files and test sources Editing : This check runs on the fly in the IDE editor Implementation : [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/compose/ui/ui-lint/src/main/java/androidx/compose/ui/lint/ModifierDeclarationDetector.kt) Tests : [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/compose/ui/ui-lint/src/test/java/androidx/compose/ui/lint/ModifierDeclarationDetectorTest.kt) Copyright Year : 2020 Modifier factory functions should be defined as extension functions on Modifier to allow modifiers to be fluently chained. !!! Tip This lint check has an associated quickfix available in the IDE. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/androidx/compose/ui/foo/test.kt:6:Warning: Modifier factory functions should be extensions on Modifier [ModifierFactoryExtensionFunction] fun fooModifier(): Modifier { ----------- src/androidx/compose/ui/foo/test.kt:10:Warning: Modifier factory functions should be extensions on Modifier [ModifierFactoryExtensionFunction] val fooModifier get(): Modifier { ----------- src/androidx/compose/ui/foo/test.kt:14:Warning: Modifier factory functions should be extensions on Modifier [ModifierFactoryExtensionFunction] val fooModifier2: Modifier get() { ------------ src/androidx/compose/ui/foo/test.kt:18:Warning: Modifier factory functions should be extensions on Modifier [ModifierFactoryExtensionFunction] val fooModifier3: Modifier get() = Modifier ------------ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/androidx/compose/ui/foo/test.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package androidx.compose.ui.foo import androidx.compose.ui.Modifier fun fooModifier(): Modifier { return Modifier } val fooModifier get(): Modifier { return Modifier } val fooModifier2: Modifier get() { return Modifier } val fooModifier3: Modifier get() = Modifier ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/compose/ui/ui-lint/src/test/java/androidx/compose/ui/lint/ModifierDeclarationDetectorTest.kt) for the unit tests for this check to see additional scenarios. The above example was automatically extracted from the first unit test found for this lint check, `ModifierDeclarationDetector.noModifierReceiver`. To report a problem with this extracted sample, visit https://issuetracker.google.com/issues/new?component=612128. (##) Including !!! This is not a built-in check. To include it, add the below dependency to your project. ``` // build.gradle.kts implementation("androidx.compose.ui:ui-android:1.9.0-alpha01") // build.gradle implementation 'androidx.compose.ui:ui-android:1.9.0-alpha01' // build.gradle.kts with version catalogs: implementation(libs.ui.android) # libs.versions.toml [versions] ui-android = "1.9.0-alpha01" [libraries] # For clarity and text wrapping purposes the following declaration is # shown split up across lines, but in TOML it needs to be on a single # line (see https://github.com/toml-lang/toml/issues/516) so adjust # when pasting into libs.versions.toml: ui-android = { module = "androidx.compose.ui:ui-android", version.ref = "ui-android" } ``` 1.9.0-alpha01 is the version this documentation was generated from; there may be newer versions available. NOTE: These lint checks are **also** made available separate from the main library. You can also use `androidx.compose.ui:ui-lint:1.9.0-alpha01`. [Additional details about androidx.compose.ui:ui-android](androidx_compose_ui_ui-android.md.html). (##) Suppressing You can suppress false positives using one of the following mechanisms: * Using a suppression annotation like this on the enclosing element: ```kt // Kotlin @Suppress("ModifierFactoryExtensionFunction") fun method() { problematicStatement() } ``` or ```java // Java @SuppressWarnings("ModifierFactoryExtensionFunction") void method() { problematicStatement(); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection ModifierFactoryExtensionFunction problematicStatement() ``` * Using a special `lint.xml` file in the source tree which turns off the check in that folder and any sub folder. A simple file might look like this: ```xml <?xml version="1.0" encoding="UTF-8"?> <lint> <issue id="ModifierFactoryExtensionFunction" severity="ignore" /> </lint> ``` Instead of `ignore` you can also change the severity here, for example from `error` to `warning`. You can find additional documentation on how to filter issues by path, regular expression and so on [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html). * In Gradle projects, using the DSL syntax to configure lint. For example, you can use something like ```gradle lintOptions { disable 'ModifierFactoryExtensionFunction' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore ModifierFactoryExtensionFunction ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).