RuleSetProvider now implements Serializable interface.

This is needed for better Gradle plugin support.

CHANGELOG.md

@@ -7,7 +7,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - New `ktlint_ignore_back_ticked_identifier` EditorConfig option for `max-line-length` rule to ignore long method names inside backticks 
   (primarily used in tests) ([#1007](https://github.com/pinterest/ktlint/issues/1007))
 - Allow to add/replace loaded `.editorconfig` values via `ExperimentalParams#editorConfigOverride` ([#1016](https://github.com/pinterest/ktlint/issues/1003))
-- `ReporterProvider` and `LintError` now implement `Serializable` interface
+- `ReporterProvider`, `LintError`, `RuleSetProvider` now implement `Serializable` interface
 ### Fixed
 - Incorrect indentation with multiple interfaces ([#1003](https://github.com/pinterest/ktlint/issues/1003))
 - Empty line before primary constructor is not reported and formatted-out ([#1004](https://github.com/pinterest/ktlint/issues/1004))

ktlint-core/src/main/kotlin/com/pinterest/ktlint/core/RuleSetProvider.kt

@@ -1,16 +1,18 @@
 package com.pinterest.ktlint.core
 
+import java.io.Serializable
+
 /**
  * `ktlint` uses [ServiceLoader](http://docs.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html) to
  * discover all available `RuleSetProvider`s on the classpath and so each `RuleSetProvider` must be registered using
  * `META-INF/services/com.pinterest.ktlint.core.RuleSetProvider`
  * (see `ktlint-ruleset-standard/src/main/resources` for an example).
  */
-interface RuleSetProvider {
+public interface RuleSetProvider : Serializable {
 
     /**
      * This method is going to be called once for each file (which means if any of the rules have state or
      * are not thread-safe - a new RuleSet must be created).
      */
-    fun get(): RuleSet
+    public fun get(): RuleSet
 }

ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/StandardRuleSetProvider.kt

@@ -3,7 +3,7 @@ package com.pinterest.ktlint.ruleset.standard
 import com.pinterest.ktlint.core.RuleSet
 import com.pinterest.ktlint.core.RuleSetProvider
 
-class StandardRuleSetProvider : RuleSetProvider {
+public class StandardRuleSetProvider : RuleSetProvider {
 
     // Note: some of these rules may be disabled by default. See the default .editorconfig.
     override fun get(): RuleSet = RuleSet(

ktlint-ruleset-template/src/main/kotlin/yourpkgname/CustomRuleSetProvider.kt

@@ -3,7 +3,7 @@ package yourpkgname
 import com.pinterest.ktlint.core.RuleSet
 import com.pinterest.ktlint.core.RuleSetProvider
 
-class CustomRuleSetProvider : RuleSetProvider {
+public class CustomRuleSetProvider : RuleSetProvider {
 
     override fun get(): RuleSet = RuleSet("custom", NoVarRule())
 }