Don't mark named unicode character as an error in Python 3.8+ (PY-36004)

GitOrigin-RevId: 59b52a42e5c820a6603e6734e768f035c5c593e5

python/src/com/jetbrains/python/psi/impl/PyStringLiteralExpressionImpl.java

@@ -40,6 +40,7 @@ import com.jetbrains.python.psi.types.TypeEvalContext;
 import one.util.streamex.StreamEx;
 import org.intellij.lang.regexp.DefaultRegExpPropertiesProvider;
 import org.intellij.lang.regexp.RegExpLanguageHost;
+import org.intellij.lang.regexp.UnicodeCharacterNames;
 import org.intellij.lang.regexp.psi.*;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -422,4 +423,14 @@ public class PyStringLiteralExpressionImpl extends PyElementImpl implements PySt
   public String[][] getKnownCharacterClasses() {
     return myPropertiesProvider.getKnownCharacterClasses();
   }
+
+  @Override
+  public boolean supportsNamedCharacters(RegExpNamedCharacter namedCharacter) {
+    return LanguageLevel.forElement(this).isAtLeast(LanguageLevel.PYTHON38);
+  }
+
+  @Override
+  public boolean isValidNamedCharacter(RegExpNamedCharacter namedCharacter) {
+    return UnicodeCharacterNames.getCodePoint(namedCharacter.getName()) >= 0;
+  }
 }

python/testData/highlighting/namedUnicode.py

@@ -0,0 +1,3 @@
+import re
+re.match(r'\N{LESS-THAN SIGN}', '<')
+re.match(r'\N{<error descr="Unknown character name">LESS-THAN SIG</error>}', '<')

python/testData/highlighting/namedUnicodeBefore38.py

@@ -0,0 +1,3 @@
+import re
+re.match(r'<error descr="Named Unicode characters are not allowed in this regex dialect">\N{LESS-THAN SIGN}</error>', '<')
+re.match(r'<error descr="Named Unicode characters are not allowed in this regex dialect">\N{LESS-THAN SIG}</error>', '<')

python/testSrc/com/jetbrains/python/PythonHighlightingTest.java

@@ -436,6 +436,16 @@ public class PythonHighlightingTest extends PyTestCase {
     doTest(LanguageLevel.PYTHON37, false, false);
   }
 
+  // PY-36004
+  public void testNamedUnicodeBefore38() {
+    doTest(LanguageLevel.PYTHON37, false, false);
+  }
+
+  // PY-36004
+  public void testNamedUnicode() {
+    doTest(LanguageLevel.PYTHON38, false, false);
+  }
+
   @NotNull
   private static EditorColorsScheme createTemporaryColorScheme() {
     EditorColorsManager manager = EditorColorsManager.getInstance();