(#) Prefer List over Array !!! WARNING: Prefer List over Array This is a warning. Id : `MoshiUsageArray` Summary : Prefer List over Array Severity : Warning Category : Correctness Platform : Any Vendor : slack Identifier : slack-lint Contact : https://github.com/slackhq/slack-lints Feedback : https://github.com/slackhq/slack-lints Min : Lint 8.7+ Compiled : Lint 8.7+ Artifact : [com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html) 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/slack-lints/tree/main/slack-lint-checks/src/main/java/slack/lint/MoshiUsageDetector.kt) Tests : [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/MoshiUsageDetectorTest.kt) Copyright Year : 2021 Array types are not supported by Moshi, please use a List instead. Arrays are expensive to manage in JSON as we don't know lengths ahead of time and they are a mutable code smell in what should be immutable value classes. Otherwise, moshi-gson-interop will hand serialization of this property to Gson, which may or may not handle it. This will eventually become an error after GSON is removed. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/slack/model/Example.kt:43:Warning: Prefer List over Array. [MoshiUsageArray] val arrayType: Array<String>, ------------- src/slack/model/Example.kt:44:Warning: Prefer List over Array. [MoshiUsageArray] val intArray: IntArray, -------- src/slack/model/Example.kt:45:Warning: Prefer List over Array. [MoshiUsageArray] val boolArray: BooleanArray, ------------ src/slack/model/Example.kt:46:Warning: Prefer List over Array. [MoshiUsageArray] val complexArray: Array<List<String>>, ------------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here are the relevant source files: `src/external/ExternalType.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package external class ExternalType ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `src/external/ExternalTypeAnnotated.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package external import com.squareup.moshi.JsonClass @JsonClass(generateAdapter = true) data class ExternalTypeAnnotated(val value: String) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `src/slack/model/Example.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package slack.model import androidx.annotation.Keep import com.squareup.moshi.JsonAdapter import com.squareup.moshi.JsonClass import java.util.ArrayList import java.util.HashSet import java.util.HashMap import java.util.Date import external.ExternalType import external.ExternalTypeAnnotated import slack.InternalType import slack.InternalTypeAnnotated import slack.InternalTypeAnnotated2 import dev.zacsweers.moshix.adapters.AdaptedBy import test.CustomQualifier @JsonClass(generateAdapter = true) data class Example( // collections val okList: List, val okSet: Set, val okCollection: Collection, val okMap: Map, val concreteList: ArrayList, val concreteSet: HashSet, val concreteMap: HashMap, // platform val platformType: Date, @AdaptedBy(DateFactory::class) val adaptedByOk: Date, // external val externalType: ExternalType, val externalTypeAnnotated: ExternalTypeAnnotated, // internal val internalType: InternalType, val internalTypeAnnotated: InternalTypeAnnotated, val internalTypeAnnotated2: InternalTypeAnnotated2, val int: Int, val string: String, val nullableString: String?, val any: Any, // Arrays val arrayType: Array, val intArray: IntArray, val boolArray: BooleanArray, val complexArray: Array>, val badGeneric: List, val badGeneric2: CustomGenericType, val badNestedGeneric: CustomGenericType>, // This would normally error but since it has a custom qualifier we skip the check @CustomQualifier val customQualifier: Date, // Mutable collections val mutableList: MutableList, val mutableSet: MutableSet, val mutableCollection: MutableCollection, val mutableMap: MutableMap ) @Keep abstract class DateFactory : JsonAdapter.Factory @JsonClass(generateAdapter = true) data class CustomGenericType(val value: T) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/MoshiUsageDetectorTest.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, `MoshiUsageDetector.propertyTypes`. To report a problem with this extracted sample, visit https://github.com/slackhq/slack-lints. (##) 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:slack-lint-checks:0.8.2") // build.gradle lintChecks 'com.slack.lint:slack-lint-checks:0.8.2' // build.gradle.kts with version catalogs: lintChecks(libs.slack.lint.checks) # libs.versions.toml [versions] slack-lint-checks = "0.8.2" [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: slack-lint-checks = { module = "com.slack.lint:slack-lint-checks", version.ref = "slack-lint-checks" } ``` 0.8.2 is the version this documentation was generated from; there may be newer versions available. [Additional details about com.slack.lint:slack-lint-checks](com_slack_lint_slack-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("MoshiUsageArray") fun method() { problematicStatement() } ``` or ```java // Java @SuppressWarnings("MoshiUsageArray") void method() { problematicStatement(); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection MoshiUsageArray 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="MoshiUsageArray" 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 'MoshiUsageArray' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore MoshiUsageArray ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).