analyzer: Support digit separators in use_full_hex rule

Work towards #56188

Cq-Include-Trybots: luci.dart.try:flutter-analyze-try,analyzer-win-release-try,pkg-win-release-try
Change-Id: I75897ffdcacd3613b9e5f5095932f514c4653fac
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/375780
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

Author: srawlins

pkg/analysis_server/lib/src/services/correction/dart/replace_with_eight_digit_hex.dart

@@ -5,11 +5,14 @@
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:analyzer_plugin/utilities/range_factory.dart';
 
 class ReplaceWithEightDigitHex extends ResolvedCorrectionProducer {
+  static final _underscoresPattern = RegExp('_+');
+
   /// The replacement text, used as an argument to the fix message.
   String _replacement = '';
 
@@ -30,22 +33,23 @@ class ReplaceWithEightDigitHex extends ResolvedCorrectionProducer {
 
   @override
   Future<void> compute(ChangeBuilder builder) async {
-    //
-    // Extract the information needed to build the edit.
-    //
-    if (node is! IntegerLiteral) {
-      return;
-    }
-    var value = (node as IntegerLiteral).value;
-    if (value == null) {
-      return;
+    if (node case (IntegerLiteral(:var value?, :var literal))) {
+      var replacementDigits = value.toRadixString(16).padLeft(8, '0');
+      if (literal.type == TokenType.HEXADECIMAL_WITH_SEPARATORS) {
+        // The original string should be a substring of the replacement
+        // (ignoring the '0x'). If there are existing separators, preserve them.
+        var originalDigits = literal.lexeme.substring('0x'.length);
+        var originalWithoutSeparators =
+            originalDigits.replaceAll(_underscoresPattern, '');
+        var numberOfDigitsToAdd =
+            replacementDigits.length - originalWithoutSeparators.length;
+        var newLeadingDigits = '0' * numberOfDigitsToAdd;
+        replacementDigits = '$newLeadingDigits$originalDigits';
+      }
+      _replacement = '0x$replacementDigits';
+      await builder.addDartFileEdit(file, (builder) {
+        builder.addSimpleReplacement(range.node(node), _replacement);
+      });
     }
-    _replacement = '0x${value.toRadixString(16).padLeft(8, '0')}';
-    //
-    // Build the edit.
-    //
-    await builder.addDartFileEdit(file, (builder) {
-      builder.addSimpleReplacement(range.node(node), _replacement);
-    });
   }
 }

pkg/analysis_server/test/src/services/correction/fix/replace_with_eight_digit_hex_test.dart

@@ -53,7 +53,7 @@ class ReplaceWithEightDigitHexTest extends FixProcessorLintTest {
   @override
   String get lintCode => LintNames.use_full_hex_values_for_flutter_colors;
 
-  Future<void> test_notHex() async {
+  Future<void> test_decimal() async {
     await resolveTestCode('''
 library dart.ui;
 
@@ -74,7 +74,7 @@ class Color {
 ''');
   }
 
-  Future<void> test_short() async {
+  Future<void> test_sixDigitHex() async {
     await resolveTestCode('''
 library dart.ui;
 
@@ -89,6 +89,27 @@ library dart.ui;
 
 var c = Color(0x00000001);
 
+class Color {
+  Color(int value);
+}
+''');
+  }
+
+  Future<void> test_sixDigitHex_withSeparators() async {
+    await resolveTestCode('''
+library dart.ui;
+
+var c = Color(0x00_00_01);
+
+class Color {
+  Color(int value);
+}
+''');
+    await assertHasFix('''
+library dart.ui;
+
+var c = Color(0x0000_00_01);
+
 class Color {
   Color(int value);
 }

pkg/linter/lib/src/rules/use_full_hex_values_for_flutter_colors.dart

@@ -9,12 +9,13 @@ import '../analyzer.dart';
 import '../extensions.dart';
 
 const _desc =
-    r'Prefer an 8-digit hexadecimal integer(0xFFFFFFFF) to instantiate Color.';
+    r'Prefer an 8-digit hexadecimal integer (for example, 0xFFFFFFFF) to '
+    'instantiate a Color.';
 
 const _details = r'''
-**PREFER** an 8-digit hexadecimal integer(0xFFFFFFFF) to instantiate Color. Colors
-have four 8-bit channels, which adds up to 32 bits, so Colors are described
-using a 32 bit integer.
+**PREFER** an 8-digit hexadecimal integer (for example, 0xFFFFFFFF) to
+instantiate a Color. Colors have four 8-bit channels, which adds up to 32 bits,
+so Colors are described using a 32-bit integer.
 
 **BAD:**
 ```dart
@@ -57,6 +58,8 @@ class UseFullHexValuesForFlutterColors extends LintRule {
 }
 
 class _Visitor extends SimpleAstVisitor {
+  static final _underscoresPattern = RegExp('_+');
+
   final LintRule rule;
 
   _Visitor(this.rule);
@@ -72,6 +75,7 @@ class _Visitor extends SimpleAstVisitor {
         var argument = arguments.first;
         if (argument is IntegerLiteral) {
           var value = argument.literal.lexeme.toLowerCase();
+          value = value.replaceAll(_underscoresPattern, '');
           if (!value.startsWith('0x') || value.length != 10) {
             rule.reportLint(argument);
           }

pkg/linter/test/rules/use_full_hex_values_for_flutter_colors_test.dart

@@ -17,16 +17,29 @@ class UseFullHexValuesForFlutterColorsTest extends LintRuleTest {
   @override
   String get lintRule => 'use_full_hex_values_for_flutter_colors';
 
-  test_dynamicArgument() async {
-    await assertNoDiagnostics(r'''
+  test_decimal() async {
+    await assertDiagnostics(r'''
 library dart.ui;
 
+var c = Color(1);
+
 class Color {
   Color(int v);
 }
+''', [
+      lint(32, 1),
+    ]);
+  }
 
-void f(dynamic a) {
-  Color(a);
+  test_dynamicArgument() async {
+    await assertNoDiagnostics(r'''
+library dart.ui;
+
+dynamic a = 1;
+var c = Color(a);
+
+class Color {
+  Color(int v);
 }
 ''');
   }
@@ -35,75 +48,65 @@ void f(dynamic a) {
     await assertNoDiagnostics(r'''
 library dart.ui;
 
+var c = Color(0x00000000);
+
 class Color {
   Color(int v);
 }
-
-void f() {
-  Color(0x00000000);
-}
 ''');
   }
 
   test_eightDigitHex_upper() async {
     await assertNoDiagnostics(r'''
 library dart.ui;
 
+var c = Color(0X00000000);
+
 class Color {
   Color(int v);
 }
-
-void f() {
-  Color(0X00000000);
-}
 ''');
   }
 
-  test_nonHex() async {
+  test_sixDigitHex_lower() async {
     await assertDiagnostics(r'''
 library dart.ui;
 
+var c = Color(0x000000);
+
 class Color {
   Color(int v);
 }
-
-void f() {
-  Color(1);
-}
 ''', [
-      lint(70, 1),
+      lint(32, 8),
     ]);
   }
 
-  test_sixDigitHex_lower() async {
+  test_sixDigitHex_upper() async {
     await assertDiagnostics(r'''
 library dart.ui;
 
+var c = Color(0X000000);
+
 class Color {
   Color(int v);
 }
-
-void f() {
-  Color(0x000000);
-}
 ''', [
-      lint(70, 8),
+      lint(32, 8),
     ]);
   }
 
-  test_sixDigitHex_upper() async {
+  test_sixDigitHex_withSeparators() async {
     await assertDiagnostics(r'''
 library dart.ui;
 
+var c = Color(0x00_00_00);
+
 class Color {
   Color(int v);
 }
-
-void f() {
-  Color(0X000000);
-}
 ''', [
-      lint(70, 8),
+      lint(32, 10),
     ]);
   }
 }