(#) Incorrect naming for @Composable functions !!! WARNING: Incorrect naming for @Composable functions This is a warning. Id : `ComposableNaming` Summary : Incorrect naming for @Composable functions Severity : Warning Category : Correctness Platform : Any Vendor : Jetpack Compose Identifier : androidx.compose.runtime Feedback : https://issuetracker.google.com/issues/new?component=612128 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/runtime/runtime-lint/src/main/java/androidx/compose/runtime/lint/ComposableNamingDetector.kt) Tests : [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/compose/runtime/runtime-lint/src/test/java/androidx/compose/runtime/lint/ComposableNamingDetectorTest.kt) Copyright Year : 2020 @Composable functions without a return type should use similar naming to classes, starting with an uppercase letter and ending with a noun. @Composable functions with a return type should be treated as normal Kotlin functions, starting with a lowercase letter. !!! 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/runtime/foo/test.kt:7:Warning: Composable functions that return Unit should start with an uppercase letter [ComposableNaming] fun button() {} ------ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/androidx/compose/runtime/foo/test.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package androidx.compose.runtime.foo import androidx.compose.runtime.Composable @Composable fun button() {} ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/compose/runtime/runtime-lint/src/test/java/androidx/compose/runtime/lint/ComposableNamingDetectorTest.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, `ComposableNamingDetector.returnsUnit_lowerCaseName_fails`. To report a problem with this extracted sample, visit https://issuetracker.google.com/issues/new?component=612128. (##) 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("ComposableNaming") fun method() { problematicStatement() } ``` or ```java // Java @SuppressWarnings("ComposableNaming") void method() { problematicStatement(); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection ComposableNaming 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="ComposableNaming" 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 'ComposableNaming' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore ComposableNaming ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).