(#) Constructors in Moshi classes cannot be private. !!! ERROR: Constructors in Moshi classes cannot be private. This is an error. Id : `MoshiUsagePrivateConstructor` Summary : Constructors in Moshi classes cannot be private. Severity : Error 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 8.0 and 8.1 Compiled : Lint 8.0 and 8.1 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/blob/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 Constructors in Moshi classes cannot be private. Otherwise Moshi cannot invoke it during decoding. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/slack/model/Example.kt:6:Error: Constructors in Moshi classes cannot be private. [MoshiUsagePrivateConstructor] data class Example private constructor(val value: String) ------- src/slack/model/Example.kt:9:Error: Constructors in Moshi classes cannot be private. [MoshiUsagePrivateConstructor] data class Example2 protected constructor(val value: String) --------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/slack/model/Example.kt`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers package slack.model import com.squareup.moshi.JsonClass @JsonClass(generateAdapter = true) data class Example private constructor(val value: String) @JsonClass(generateAdapter = true) data class Example2 protected constructor(val value: String) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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.private_constructor`. 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:0.7.0") // build.gradle lintChecks 'com.slack.lint:slack-lint-checks:0.7.0' // build.gradle.kts with version catalogs: lintChecks(libs.slack-lint-checks) # libs.versions.toml [versions] slack-lint-checks = "0.7.0" [libraries] slack-lint-checks = { module = "com.slack.lint:slack-lint-checks", version.ref = "slack-lint-checks" } ``` 0.7.0 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("MoshiUsagePrivateConstructor") fun method() { problematicStatement() } ``` or ```java // Java @SuppressWarnings("MoshiUsagePrivateConstructor") void method() { problematicStatement(); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection MoshiUsagePrivateConstructor 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="MoshiUsagePrivateConstructor" 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 'MoshiUsagePrivateConstructor' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore MoshiUsagePrivateConstructor ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).