Add library containing detekt rules for apollo plugins

game/plugin-detekt-rules/src/main/kotlin/org/apollo/game/plugin/detekt/ApolloPluginRuleSetProvider.kt

@@ -0,0 +1,16 @@
+package org.apollo.game.plugin.detekt
+
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.RuleSet
+import io.gitlab.arturbosch.detekt.api.RuleSetProvider
+import org.apollo.game.plugin.detekt.rules.DeclarationInScriptRule
+
+class ApolloPluginRuleSetProvider : RuleSetProvider {
+    override val ruleSetId = "apollo-plugin"
+
+    override fun instance(config: Config): RuleSet {
+        return RuleSet(ruleSetId, listOf(
+            DeclarationInScriptRule()
+        ))
+    }
+}

game/plugin-detekt-rules/src/main/kotlin/org/apollo/game/plugin/detekt/rules/DeclarationInScriptRule.kt

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+package org.apollo.game.plugin.detekt.rules
+
+import io.gitlab.arturbosch.detekt.api.*
+import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.KtObjectDeclaration
+
+class DeclarationInScriptRule : Rule() {
+    override val issue = Issue(
+        "DeclarationInScript",
+        Severity.CodeSmell,
+        "This rule reports a plugin file containing class or object declarations.",
+        Debt.FIVE_MINS
+    )
+
+    override fun visit(root: KtFile) {
+        super.visit(root)
+
+        val script = root.script ?: return
+        val declarations = script.declarations.filter { it is KtClass || it is KtObjectDeclaration }
+
+        declarations
+            .forEach {
+                report(CodeSmell(
+                    issue,
+                    Entity.from(it),
+                    message = "Declaration of ${it.name} should live in a top-level file, not a script"
+                ))
+            }
+    }
+}

game/plugin-detekt-rules/src/main/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider

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+org.apollo.game.plugin.detekt.ApolloPluginRuleSetProvider

game/plugin-detekt-rules/src/test/kotlin/org/apollo/game/plugin/detekt/rules/DeclarationInScriptRuleTest.kt

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+package org.apollo.game.plugin.detekt.rules
+
+import io.gitlab.arturbosch.detekt.test.lint
+import java.nio.file.Paths
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+internal class DeclarationInScriptRuleTest {
+    val rule = DeclarationInScriptRule()
+
+    @Test
+    fun `Finds warning in script file`() {
+        val srcPath = Paths.get(this.javaClass.getResource("/testData/example.kts").toURI())
+        val findings = rule.lint(srcPath)
+
+        assertEquals(1, findings.size)
+        assertEquals("Declaration of ExampleDeclaration should live in a top-level file, not a script", findings[0].message)
+    }
+}

game/plugin-detekt-rules/src/test/resources/testData/example.kts

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+class ExampleDeclaration {
+
+}