[K/JS] Don't add nested classes generated by plugins into ExportModel for interfaces ^KT-63184 Fixed

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/export/ExportModelGenerator.kt

@@ -323,6 +323,7 @@ class ExportModelGenerator(val context: JsIrBackendContext, val generateNamespac
                     members.addIfNotNull(exportProperty(candidate)?.withAttributesFor(candidate))
 
                 is IrClass -> {
+                    if (klass.isInterface) continue
                     val ec = exportClass(candidate)?.withAttributesFor(candidate)
                     if (ec is ExportedClass) {
                         nestedClasses.add(ec)

js/js.translator/testData/typescript-export/interfaces-in-exported-file/interfaces.d.ts

@@ -31,5 +31,10 @@ declare namespace JS_TESTS {
         }
         function processInterface(test: foo.TestInterface): string;
         function processOptionalInterface(a: foo.OptionalFieldsInterface): string;
+        interface InterfaceWithCompanion {
+            readonly __doNotUseOrImplementIt: {
+                readonly "foo.InterfaceWithCompanion": unique symbol;
+            };
+        }
     }
 }

js/js.translator/testData/typescript-export/interfaces-in-exported-file/interfaces.kt

@@ -45,4 +45,14 @@ external interface OptionalFieldsInterface {
 
 fun processOptionalInterface(a: OptionalFieldsInterface): String {
     return "${a.required}${a.notRequired ?: "unknown"}"
+}
+
+// KT-63184
+
+interface InterfaceWithCompanion {
+    // Emulate added by plugin companion like kotlinx.serialization does
+    @Suppress("WRONG_EXPORTED_DECLARATION")
+    companion object {
+        fun foo() = "String"
+    }
 }

js/js.translator/testData/typescript-export/interfaces/interfaces.d.ts

@@ -31,5 +31,10 @@ declare namespace JS_TESTS {
         }
         function processInterface(test: foo.TestInterface): string;
         function processOptionalInterface(a: foo.OptionalFieldsInterface): string;
+        interface InterfaceWithCompanion {
+            readonly __doNotUseOrImplementIt: {
+                readonly "foo.InterfaceWithCompanion": unique symbol;
+            };
+        }
     }
 }

js/js.translator/testData/typescript-export/interfaces/interfaces.kt

@@ -41,4 +41,14 @@ external interface OptionalFieldsInterface {
 @JsExport
 fun processOptionalInterface(a: OptionalFieldsInterface): String {
     return "${a.required}${a.notRequired ?: "unknown"}"
+}
+
+// KT-63184
+@JsExport
+interface InterfaceWithCompanion {
+    // Emulate added by plugin companion like kotlinx.serialization does
+    @Suppress("WRONG_EXPORTED_DECLARATION")
+    companion object {
+        fun foo() = "String"
+    }
 }