New J2K: correctly convert number literals with underscores

#KT-32837 fixed

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/LiteralConversion.kt

@@ -54,7 +54,7 @@ class LiteralConversion : RecursiveApplicableConversionBase() {
         JKKtLiteralExpressionImpl(literal.replace("((?:\\\\)*)\\\\([0-3]?[0-7]{1,2})".toRegex()) { matchResult ->
             val leadingBackslashes = matchResult.groupValues[1]
             if (leadingBackslashes.length % 2 == 0)
-                kotlin.String.format("%s\\u%04x", leadingBackslashes, java.lang.Integer.parseInt(matchResult.groupValues[2], 8))
+                String.format("%s\\u%04x", leadingBackslashes, Integer.parseInt(matchResult.groupValues[2], 8))
             else matchResult.value
         }.replace("\\$([A-Za-z]+|\\{)".toRegex(), "\\\\$0"), JKLiteralExpression.LiteralType.STRING)
 
@@ -71,7 +71,7 @@ class LiteralConversion : RecursiveApplicableConversionBase() {
     private fun JKLiteralExpression.toIntLiteral(): JKKtLiteralExpression =
         JKKtLiteralExpressionImpl(
             literal
-                .replace("l", "", ignoreCase = true)
+                .cleanIntAndLongLiterals()
                 .convertHexLiteral(isLongLiteral = false)
                 .convertOctalLiteral(),
             JKLiteralExpression.LiteralType.INT
@@ -81,7 +81,7 @@ class LiteralConversion : RecursiveApplicableConversionBase() {
     private fun JKLiteralExpression.toLongLiteral(): JKKtLiteralExpression =
         JKKtLiteralExpressionImpl(
             literal
-                .replace("l", "", ignoreCase = true)
+                .cleanIntAndLongLiterals()
                 .convertHexLiteral(isLongLiteral = true)
                 .convertOctalLiteral() + "L",
             JKLiteralExpression.LiteralType.LONG
@@ -113,4 +113,10 @@ class LiteralConversion : RecursiveApplicableConversionBase() {
             .replace(".e", "e", ignoreCase = true)
             .replace(".f", "", ignoreCase = true)
             .replace("f", "", ignoreCase = true)
+            .replace("_", "")
+
+    private fun String.cleanIntAndLongLiterals() =
+        replace("l", "", ignoreCase = true)
+            .replace("_", "")
+
 }

nj2k/testData/newJ2k/literalExpression/underscores.java

@@ -0,0 +1,9 @@
+public class TestNumber {
+    long longLiteral = 123_456_7;
+    long longHexLiteral = 0xFF_EC_DE_5E;
+    int intLiteral = 123_4;
+    float floatLiteral = 123_4.f;
+    double doubleLiteral = 123_4d;
+    short shortLiteral = 1_2_3;
+    byte byteLiteral = 1_2_3;
+}

nj2k/testData/newJ2k/literalExpression/underscores.kt

@@ -0,0 +1,9 @@
+class TestNumber {
+    internal var longLiteral: Long = 1234567
+    internal var longHexLiteral: Long = -0x1321a2
+    internal var intLiteral = 1234
+    internal var floatLiteral = 1234f
+    internal var doubleLiteral = 1234.0
+    internal var shortLiteral: Short = 123
+    internal var byteLiteral: Byte = 123
+}

nj2k/tests/org/jetbrains/kotlin/nj2k/NewJavaToKotlinConverterSingleFileTestGenerated.java

@@ -3375,6 +3375,11 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
         public void testTrueOrFalse() throws Exception {
             runTest("nj2k/testData/newJ2k/literalExpression/trueOrFalse.java");
         }
+
+        @TestMetadata("underscores.java")
+        public void testUnderscores() throws Exception {
+            runTest("nj2k/testData/newJ2k/literalExpression/underscores.java");
+        }
     }
 
     @TestMetadata("nj2k/testData/newJ2k/localVariable")