Stop creating in-memory KtFile when file path is provided

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/KtFileModifier.kt

@@ -16,10 +16,12 @@ class KtFileModifier : FileProcessListener {
 
     override fun onFinish(files: List<KtFile>, result: Detektion) {
         files.filter { it.modifiedText != null }
-            .map { it.absolutePath() to it.unnormalizeContent() }
-            .forEach { (path, content) ->
+            .forEach { ktFile ->
+                val path = ktFile.absolutePath()
                 result.add(ModificationNotification(path))
-                path.writeText(content)
+                path.writeText(ktFile.unnormalizeContent())
+                // reset modification text after writing as the PsiFile may be reused in tests or an IDE session
+                ktFile.modifiedText = null
             }
     }
 

detekt-formatting/src/test/kotlin/io/gitlab/arturbosch/detekt/formatting/AutoCorrectLevelSpec.kt

@@ -75,6 +75,9 @@ private fun createConfig(ruleSet: AutoCorrectConfig, rule: AutoCorrectConfig): S
 
 private fun runRule(config: Config): Pair<KtFile, List<Finding>> {
     val testFile = loadFile("configTests/fixed.kt")
+    // reset modification text, otherwise it will be persisted between tests
+    testFile.modifiedText = null
+
     val ruleSet = loadRuleSet<FormattingProvider>()
     val rules = ruleSet.rules
         .map { (ruleId, provider) -> provider(config.subConfig(ruleSet.id.value).subConfig(ruleId.value)) }

detekt-parser/src/main/kotlin/io/github/detekt/parser/KtCompiler.kt

@@ -4,13 +4,13 @@ import io.github.detekt.psi.absolutePath
 import org.intellij.lang.annotations.Language
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.com.intellij.openapi.util.text.StringUtilRt
+import org.jetbrains.kotlin.com.intellij.psi.util.PsiUtilCore
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtPsiFactory
 import java.nio.file.Path
 import kotlin.io.path.absolute
 import kotlin.io.path.isRegularFile
 import kotlin.io.path.name
-import kotlin.io.path.readText
 
 open class KtCompiler(
     protected val environment: KotlinCoreEnvironment = createKotlinCoreEnvironment(printStream = System.err)
@@ -20,7 +20,11 @@ open class KtCompiler(
 
     fun compile(path: Path): KtFile {
         require(path.isRegularFile()) { "Given path '$path' should be a regular file!" }
-        return createKtFile(path.readText(), path)
+
+        val virtualFile = requireNotNull(environment.findLocalFile(path.toString()))
+        return requireNotNull(PsiUtilCore.getPsiFile(environment.project, virtualFile) as? KtFile) {
+            "$path is not a Kotlin file"
+        }
     }
 
     fun createKtFile(@Language("kotlin") content: String, path: Path): KtFile {

detekt-parser/src/test/kotlin/io/github/detekt/parser/KtCompilerSpec.kt

@@ -3,7 +3,6 @@ package io.github.detekt.parser
 import io.github.detekt.test.utils.resourceAsPath
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatIllegalArgumentException
-import org.jetbrains.kotlin.com.intellij.psi.PsiErrorElement
 import org.jetbrains.kotlin.psi.KtTreeVisitorVoid
 import org.junit.jupiter.api.Nested
 import org.junit.jupiter.api.Test
@@ -52,17 +51,11 @@ class KtCompilerSpec {
 
         @Test
         fun `parses with errors for non kotlin files`() {
-            val cssPath = resourceAsPath("css")
-            val ktFile = ktCompiler.compile(cssPath.resolve("test.css"))
+            val cssPath = resourceAsPath("css/test.css")
 
-            val errors = mutableListOf<PsiErrorElement>()
-            ktFile.accept(object : KtTreeVisitorVoid() {
-                override fun visitErrorElement(element: PsiErrorElement) {
-                    errors.add(element)
-                }
-            })
-
-            assertThat(errors).isNotEmpty()
+            assertThatIllegalArgumentException()
+                .isThrownBy { ktCompiler.compile(cssPath) }
+                .withMessage("$cssPath is not a Kotlin file")
         }
     }