(#) Unstable receivers will always be recomposed !!! WARNING: Unstable receivers will always be recomposed This is a warning. Id : `ComposeUnstableReceiver` Summary : Unstable receivers will always be recomposed Severity : Warning Category : Productivity Platform : Any Vendor : slack Identifier : com.slack.lint.compose:compose-lints Feedback : https://github.com/slackhq/compose-lints/issues Min : Lint 8.7+ Compiled : Lint 8.7+ Artifact : [com.slack.lint.compose:compose-lint-checks](com_slack_lint_compose_compose-lint-checks.md.html) Since : 1.3.0 Affects : Kotlin and Java files and test sources Editing : This check runs on the fly in the IDE editor Implementation : [Source Code](https://github.com/slackhq/compose-lints/tree/main/compose-lint-checks/src/main/java/slack/lint/compose/UnstableReceiverDetector.kt) Tests : [Source Code](https://github.com/slackhq/compose-lints/tree/main/compose-lint-checks/src/test/java/slack/lint/compose/UnstableReceiverDetectorTest.kt) Copyright Year : 2023 Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/ExampleInterface.kt:4:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] @Composable fun Content() ------- src/ExampleInterface.kt:8:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] @Composable fun Content() {} ------- src/ExampleInterface.kt:12:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] fun Example.OtherContent() {} ------- src/ExampleInterface.kt:15:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] val Example.OtherContentProperty get() {} ------- src/ExampleInterface.kt:19:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] @Composable fun present(): T ------- src/ExampleInterface.kt:23:Warning: Instance composable functions on non-stable classes will always be recomposed. If possible, make the receiver type stable or refactor this function if that isn't possible. See https://slackhq.github.io/compose-lints/rules/#unstable-receivers for more information. [ComposeUnstableReceiver] @Composable override fun present(): String { return "hi" } ------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/ExampleInterface.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers import androidx.compose.runtime.Composable interface ExampleInterface { @Composable fun Content() } class Example { @Composable fun Content() {} } @Composable fun Example.OtherContent() {} @get:Composable val Example.OtherContentProperty get() {} // Supertypes interface Presenter { @Composable fun present(): T } class HomePresenter : Presenter { @Composable override fun present(): String { return "hi" } } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://github.com/slackhq/compose-lints/tree/main/compose-lint-checks/src/test/java/slack/lint/compose/UnstableReceiverDetectorTest.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, `UnstableReceiverDetector.unstable receiver types report errors`. To report a problem with this extracted sample, visit https://github.com/slackhq/compose-lints/issues. (##) Including !!! This is not a built-in check. To include it, add the below dependency to your project. This lint check is included in the lint documentation, but the Android team may or may not agree with its recommendations. ``` // build.gradle.kts lintChecks("com.slack.lint.compose:compose-lint-checks:1.4.2") // build.gradle lintChecks 'com.slack.lint.compose:compose-lint-checks:1.4.2' // build.gradle.kts with version catalogs: lintChecks(libs.compose.lint.checks) # libs.versions.toml [versions] compose-lint-checks = "1.4.2" [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: compose-lint-checks = { module = "com.slack.lint.compose:compose-lint-checks", version.ref = "compose-lint-checks" } ``` 1.4.2 is the version this documentation was generated from; there may be newer versions available. [Additional details about com.slack.lint.compose:compose-lint-checks](com_slack_lint_compose_compose-lint-checks.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("ComposeUnstableReceiver") fun method() { problematicStatement() } ``` or ```java // Java @SuppressWarnings("ComposeUnstableReceiver") void method() { problematicStatement(); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection ComposeUnstableReceiver 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="ComposeUnstableReceiver" 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 'ComposeUnstableReceiver' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore ComposeUnstableReceiver ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).