[Gradle, JS] Correct require relative path

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformer.kt

@@ -253,7 +253,7 @@ class IrModuleToJsTransformer(
             }
 
             val moduleName = declareFreshGlobal(module.safeName)
-            modules += JsImportedModule(module.externalModuleName(), moduleName, null, relativeRequirePath)
+            modules += JsImportedModule(module.externalModuleName(), moduleName, null, null)
 
             names.forEach {
                 imports += JsVars(JsVars.JsVar(JsName(it, false), JsNameRef(it, ReservedJsNames.makeCrossModuleNameRef(moduleName))))

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/JsIrProgramFragment.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.backend.js.transformers.irToJs
 
 import org.jetbrains.kotlin.ir.backend.js.utils.toJsIdentifier
 import org.jetbrains.kotlin.js.backend.ast.*
+import java.io.File
 
 class JsIrProgramFragment(val packageFqn: String) {
     val nameBindings = mutableMapOf<String, JsName>()
@@ -128,7 +129,14 @@ private class JsIrModuleCrossModuleReferecenceBuilder(val header: JsIrModuleHead
         fun import(moduleHeader: JsIrModuleHeader): JsName {
             return importedModules.getOrPut(moduleHeader) {
                 val jsModuleName = JsName(moduleHeader.moduleName, false)
-                JsImportedModule(moduleHeader.externalModuleName, jsModuleName, null, relativeRequirePath)
+                val relativeRequirePath = relativeRequirePath(moduleHeader)
+
+                JsImportedModule(
+                    moduleHeader.externalModuleName,
+                    jsModuleName,
+                    null,
+                    relativeRequirePath
+                )
             }.internalName
         }
 
@@ -149,6 +157,21 @@ private class JsIrModuleCrossModuleReferecenceBuilder(val header: JsIrModuleHead
         }
         return CrossModuleReferences(importedModules.values.toList(), transitiveExport, exportNames, resultImports)
     }
+
+    private fun relativeRequirePath(moduleHeader: JsIrModuleHeader): String? {
+        if (!this.relativeRequirePath) return null
+
+        val parentMain = File(header.externalModuleName).parentFile
+
+        if (parentMain == null) return "./${moduleHeader.externalModuleName}"
+
+        val relativePath = File(moduleHeader.externalModuleName)
+            .toRelativeString(parentMain)
+            .replace(File.separator, "/")
+
+        return relativePath.takeIf { it.startsWith("../") }
+            ?: "./$relativePath"
+    }
 }
 
 class CrossModuleImport(val exportedAs: String, val moduleExporter: JsName)

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsImportedModule.kt

@@ -21,12 +21,12 @@ class JsImportedModule @JvmOverloads constructor(
     val externalName: String,
     var internalName: JsName,
     val plainReference: JsExpression?,
-    val relativeRequirePath: Boolean = false
+    val relativeRequirePath: String? = null
 ) {
     val key = JsImportedModuleKey(externalName, plainReference?.toString())
 }
 
 val JsImportedModule.requireName: String
-    get() = if (relativeRequirePath) "./$externalName.js" else externalName
+    get() = relativeRequirePath?.let { "$it.js" } ?: externalName
 
 data class JsImportedModuleKey(val baseName: String, val plainName: String?)