[messages] Handle camelCase-formatted files.

Updates the logic in `pkg/analyzer_utilities` and
`pkg/front_end/test/messages_suite.dart` for processing
`messages.yaml` files so that:

- Message keys in analyzer-style `messages.yaml` files can be
  `camelCase`, `lower_snake_case`, or `UPPER_SNAKE_CASE` (previously
  they could only be `lower_snake_case` or `UPPER_SNAKE_CASE`).

- Message keys in CFE-style `messages.yaml` files can be either
  `camelCase` or `PascalCase` (previously they could only be
  `PascalCase`).

- `sharedName` fields can be `camelCase`, `lower_snake_case`, or
  `UPPER_SNAKE_CASE` (previously they could only be `lower_snake_case`
  or `UPPER_SNAKE_CASE`).

- `analyzerCode` fields in `pkg/_fe_analyzer_shared/messages.yaml` can
  be `ClassName.lower_snake_case`, `ClassName.UPPER_SNAKE_CASE`, or
  `camelCase`, where `ClassName` is ignored (previously they could
  only be `ClassName.lower_snake_case` or
  `ClassName.UPPER_SNAKE_CASE`).

This paves the way for a follow-up CL in which all these fields and
keys will be standardized to `camelCase`, and then the ability to
specify them in `lower_snake_case` or `UPPER_SNAKE_CASE` will be
removed. This will eliminate a significant inconsistency between the
diagnostic code formats in the analyzer and the front end.

Note that a few diagnostic names contain an underscore immediately
followed by a digit in their snake case representation:

- `final_not_initialized_constructor_1`
- `final_not_initialized_constructor_2`
- `final_not_initialized_constructor_3_plus`
- `lines_longer_than_80_chars`

When these are converted to `camelCase` form, the code generator will
no longer know to introduce the underscores when converting them back
to `snake_case` form (e.g. `finalNotInitializedConstructor1` will get
converted to `final_not_initialized_constructor1`). The snake case
forms are an important part of the customer facing API (since they are
what is accepted in `// ignore:` comments), so in order to preserve
the existing snake case names, a hardcoded map is introduced,
`_snakeCaseExceptions`.

Change-Id: I6a6a696444ccd92dd6574a7cde08da88ac5a7135
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/466540
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/analyzer_utilities/lib/analyzer_messages.dart

@@ -196,7 +196,9 @@ List<M> decodeAnalyzerMessagesYaml<M extends AnalyzerMessage>(
         key: keyNode,
         value: diagnosticValue,
         decoder: (messageYaml) {
-          var analyzerCode = DiagnosticCodeName(snakeCaseName: diagnosticName);
+          var analyzerCode = DiagnosticCodeName.fromCamelOrSnakeCase(
+            diagnosticName,
+          );
           return decodeMessage(
             messageYaml,
             analyzerCode: analyzerCode,

pkg/analyzer_utilities/lib/messages.dart

@@ -153,7 +153,7 @@ abstract class CfeStyleMessage extends Message {
   ///
   /// This is the key corresponding to the diagnostic's entry in
   /// `messages.yaml`.
-  final String frontEndCode;
+  final DiagnosticCodeName frontEndCode;
 
   CfeStyleMessage(MessageYaml messageYaml)
     : cfeSeverity = messageYaml.get(
@@ -172,7 +172,18 @@ abstract class CfeStyleMessage extends Message {
         },
         ifAbsent: () => null,
       ),
-      frontEndCode = messageYaml.keyString,
+      frontEndCode = switch (messageYaml.keyString) {
+        var s when s.isCamelCase => DiagnosticCodeName.fromCamelCase(
+          messageYaml.keyString,
+        ),
+        var s when s.isPascalCase => DiagnosticCodeName.fromPascalCase(
+          messageYaml.keyString,
+        ),
+        _ => throw LocatedError(
+          'Front end codes must be camelCase or PascalCase',
+          span: messageYaml.keySpan,
+        ),
+      },
       super(messageYaml, requireProblemMessage: true) {
     // Ignore extra keys related to front end example-based tests.
     messageYaml.allowExtraKeys({
@@ -211,24 +222,74 @@ sealed class Conversion {
 /// This class implements [Comparable], so lists of it can be safely
 /// [List.sort]ed.
 class DiagnosticCodeName implements Comparable<DiagnosticCodeName> {
-  /// The diagnostic name.
+  /// Exceptions to the usual rules for converting diagnostic code names from
+  /// camel case to snake case.
   ///
-  /// The diagnostic name is in "snake case", meaning it consists of words
-  /// separated by underscores. Those words might be lower case or upper case.
+  /// Normally, diagnostic code names are converted from camel case to snake
+  /// case using [StringExtension.toSnakeCase]. But in rare situations when the
+  /// name contains numbers, this can produce results that aren't ideal. Rather
+  /// than try to fix these rare situations in a general fashion, it's easier to
+  /// just have an explicit map of the problematic names, with their preferred
+  /// snake case forms.
+  static const Map<String, String> _snakeCaseExceptions = {
+    'finalNotInitializedConstructor1': 'final_not_initialized_constructor_1',
+    'finalNotInitializedConstructor2': 'final_not_initialized_constructor_2',
+    'finalNotInitializedConstructor3Plus':
+        'final_not_initialized_constructor_3_plus',
+    'linesLongerThan80Chars': 'lines_longer_than_80_chars',
+  };
+
+  /// The diagnostic name, as a "snake case" name (words separated by
+  /// underscores).
   ///
+  /// The name might be lower case or upper case.
   // TODO(paulberry): change `messages.yaml` to consistently use lower snake
   // case, and remove [lowerSnakeCaseName].
   final String snakeCaseName;
 
-  DiagnosticCodeName({required this.snakeCaseName});
+  /// The diagnostic name, as a "camel case" name (lower case word followed by
+  /// capitalized words, with no separation between words).
+  final String camelCaseName;
+
+  DiagnosticCodeName.fromCamelCase(this.camelCaseName)
+    : snakeCaseName =
+          _snakeCaseExceptions[camelCaseName] ?? camelCaseName.toSnakeCase() {
+    if (snakeCaseName.toLowerCase() != snakeCaseName) {
+      throw 'Snake case name ${json.encode(snakeCaseName)} is not all lower '
+          'case';
+    }
+    if (snakeCaseName.toCamelCase() != camelCaseName) {
+      throw 'Round-trip conversion from ${json.encode(camelCaseName)} to snake '
+          'case and back produces ${json.encode(snakeCaseName.toCamelCase())}';
+    }
+  }
+
+  factory DiagnosticCodeName.fromCamelOrSnakeCase(String value) =>
+      value.isCamelCase
+      ? DiagnosticCodeName.fromCamelCase(value)
+      : DiagnosticCodeName.fromSnakeCase(value);
+
+  factory DiagnosticCodeName.fromPascalCase(String pascalCaseName) {
+    var snakeCaseName = pascalCaseName.toSnakeCase();
+    var camelCaseName = snakeCaseName.toPascalCase();
+    return DiagnosticCodeName._(
+      snakeCaseName: snakeCaseName,
+      camelCaseName: camelCaseName,
+    );
+  }
+
+  DiagnosticCodeName.fromSnakeCase(this.snakeCaseName)
+    : camelCaseName = snakeCaseName.toCamelCase();
+
+  DiagnosticCodeName._({
+    required this.snakeCaseName,
+    required this.camelCaseName,
+  });
 
   /// The string that should be generated into analyzer source code to refer to
   /// this diagnostic code.
   String get analyzerCodeReference => ['diag', camelCaseName].join('.');
 
-  /// The diagnostic name, converted to camel case.
-  String get camelCaseName => snakeCaseName.toCamelCase();
-
   @override
   int get hashCode => snakeCaseName.hashCode;
 
@@ -410,7 +471,7 @@ class DiagnosticTables {
   activeMessagesByPackage = {};
 
   DiagnosticTables._(List<Message> messages) {
-    var frontEndCodeDuplicateChecker = _DuplicateChecker<String>(
+    var frontEndCodeDuplicateChecker = _DuplicateChecker<DiagnosticCodeName>(
       kind: 'Front end code',
     );
     var analyzerCodeDuplicateChecker = _DuplicateChecker<DiagnosticCodeName>(
@@ -602,7 +663,7 @@ abstract class Message {
           ) ??
           [],
       sharedName = switch (messageYaml.getOptionalString('sharedName')) {
-        var s? => DiagnosticCodeName(snakeCaseName: s),
+        var s? => DiagnosticCodeName.fromCamelOrSnakeCase(s),
         null => null,
       },
       removedIn = messageYaml.getOptionalString('removedIn'),
@@ -949,10 +1010,13 @@ class SharedMessage extends CfeStyleMessage with MessageWithAnalyzerCode {
         switch (s.split('.')) {
           case [_, var snakeCaseName]
               when snakeCaseName == snakeCaseName.toUpperCase():
-            return DiagnosticCodeName(snakeCaseName: snakeCaseName);
+            return DiagnosticCodeName.fromSnakeCase(snakeCaseName);
+          case [var camelCaseName] when camelCaseName.isCamelCase:
+            return DiagnosticCodeName.fromCamelCase(camelCaseName);
         }
     }
-    throw 'Analyzer codes must take the form ClassName.DIAGNOSTIC_NAME.';
+    throw 'Analyzer codes must be either camelCase names or must take the form '
+        'ClassName.DIAGNOSTIC_NAME.';
   }
 }
 

pkg/front_end/test/messages_suite.dart

@@ -13,6 +13,7 @@ import 'package:_fe_analyzer_shared/src/messages/diagnostic_message.dart'
         getMessageRelatedInformation;
 import 'package:_fe_analyzer_shared/src/messages/severity.dart'
     show CfeSeverity, severityEnumValues;
+import 'package:analyzer_utilities/extensions/string.dart';
 import 'package:front_end/src/api_prototype/compiler_options.dart'
     show CompilerOptions, parseExperimentalArguments, parseExperimentalFlags;
 import 'package:front_end/src/api_prototype/experimental_flags.dart'
@@ -176,9 +177,11 @@ class MessageTestSuite extends ChainContext {
     File file = new File.fromUri(uri);
     String fileContent = file.readAsStringSync();
     YamlMap messages = loadYamlNode(fileContent, sourceUrl: uri) as YamlMap;
-    for (String name in messages.keys) {
+    for (String camelCaseName in messages.keys) {
       try {
-        YamlMap messageNode = messages.nodes[name] as YamlMap;
+        // TODO(paulberry): switch CFE to camelCase conventions.
+        var name = camelCaseName.toSnakeCase().toPascalCase();
+        YamlMap messageNode = messages.nodes[camelCaseName] as YamlMap;
         dynamic message = messageNode.value;
         if (message is String) continue;
 
@@ -552,7 +555,7 @@ class MessageTestSuite extends ChainContext {
           ),
         );
       } catch (e, st) {
-        Error.throwWithStackTrace('While processing $name: $e', st);
+        Error.throwWithStackTrace('While processing $camelCaseName: $e', st);
       }
     }
     return result;

pkg/front_end/test/spell_checking_list_tests.txt

@@ -631,6 +631,7 @@ parallax
 parameterized
 partfoo
 party
+pascal
 pause
 paused
 pays

pkg/front_end/tool/generate_messages_lib.dart

@@ -152,7 +152,7 @@ class _TemplateCompiler {
   _TemplateCompiler({
     required this.message,
     required this.pseudoSharedCodeValues,
-  }) : name = message.frontEndCode,
+  }) : name = message.frontEndCode.pascalCaseName,
        problemMessage = message.problemMessage,
        correctionMessage = message.correctionMessage,
        severity = message.cfeSeverity,