[GR-44557] TruffleStrings: don't evaluate codeRange for mutable strings in isCompatibleTo.

PullRequest: graal/13934

Author: djoooooe

truffle/src/com.oracle.truffle.api.strings.test/src/com/oracle/truffle/api/strings/test/TStringCornerCaseTests.java

@@ -110,4 +110,11 @@ public void testNegativeCodepoint() {
         TruffleString a = TruffleString.fromByteArrayUncached(byteArray(0x8e, 0xa2, 0xa1, 0xa1), TruffleString.Encoding.EUC_TW);
         Assert.assertEquals(0x8ea2a1a1, a.codePointAtByteIndexUncached(0, TruffleString.Encoding.EUC_TW, TruffleString.ErrorHandling.RETURN_NEGATIVE));
     }
+
+    @Test
+    public void testMutableImpreciseCodeRange() {
+        MutableTruffleString a = MutableTruffleString.fromByteArrayUncached(new byte[]{0}, 0, 1, TruffleString.Encoding.BYTES, false);
+        Assert.assertTrue(a.isCompatibleToUncached(TruffleString.Encoding.BYTES));
+        Assert.assertEquals(TruffleString.CodeRange.VALID, a.getCodeRangeImpreciseUncached(TruffleString.Encoding.BYTES));
+    }
 }

truffle/src/com.oracle.truffle.api.strings/src/com/oracle/truffle/api/strings/AbstractTruffleString.java

@@ -229,7 +229,9 @@ public final boolean isCompatibleTo(TruffleString.Encoding expectedEncoding) {
      */
     @TruffleBoundary
     public final boolean isCompatibleToUncached(TruffleString.Encoding expectedEncoding) {
-        getCodeRangeUncached(Encoding.get(encoding));
+        if (isImmutable() && !isCompatibleToIntl(expectedEncoding)) {
+            getCodeRangeUncached(Encoding.get(encoding));
+        }
         return isCompatibleToIntl(expectedEncoding);
     }