From fed86a57e387b9f347cd5c1b45d00da48cbbf220 Mon Sep 17 00:00:00 2001
From: Pavel Mikhailovskii <pavel.mikhailovskii@jetbrains.com>
Date: Wed, 4 Jan 2023 11:28:08 +0000
Subject: [PATCH] Fix isValidJavaFqName

---
 .../tests/org/jetbrains/kotlin/name/FqNameTest.java    | 10 +++++++++-
 .../src/org/jetbrains/kotlin/name/FqNamesUtil.kt       |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/compiler/tests/org/jetbrains/kotlin/name/FqNameTest.java b/compiler/tests/org/jetbrains/kotlin/name/FqNameTest.java
index 28c6cd8f5e3..57750af1e40 100644
--- a/compiler/tests/org/jetbrains/kotlin/name/FqNameTest.java
+++ b/compiler/tests/org/jetbrains/kotlin/name/FqNameTest.java
@@ -54,12 +54,19 @@ public class FqNameTest {
     public void isValidJavaFqName() {
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName(""));
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("a"));
-        Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("1"));
+        Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("a1"));
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("a.a"));
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("org.jetbrains"));
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("$"));
+        Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("_"));
         Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("org.A$B"));
+        Assert.assertTrue(FqNamesUtilKt.isValidJavaFqName("晴れの日"));
 
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName(" "));
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName(" a"));
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("a "));
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("1"));
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("1a"));
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("."));
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName(".."));
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("a."));
@@ -69,5 +76,6 @@ public class FqNameTest {
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("a.b."));
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("a.b...)"));
         Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("a.b.<special>"));
+        Assert.assertFalse(FqNamesUtilKt.isValidJavaFqName("😀"));
     }
 }
diff --git a/core/compiler.common/src/org/jetbrains/kotlin/name/FqNamesUtil.kt b/core/compiler.common/src/org/jetbrains/kotlin/name/FqNamesUtil.kt
index e56121cef92..7ddf4f9a0ea 100644
--- a/core/compiler.common/src/org/jetbrains/kotlin/name/FqNamesUtil.kt
+++ b/core/compiler.common/src/org/jetbrains/kotlin/name/FqNamesUtil.kt
@@ -55,7 +55,7 @@ fun isValidJavaFqName(qualifiedName: String?): Boolean {
     for (c in qualifiedName) {
         when (state) {
             State.BEGINNING, State.AFTER_DOT -> {
-                if (!Character.isJavaIdentifierPart(c)) return false
+                if (!Character.isJavaIdentifierStart(c)) return false
                 state = State.MIDDLE
             }
             State.MIDDLE -> {