[analyzer]: Move some string extensions into analyzer_utilities.

The string extensions `toCamelCase` and `toPascalCase` are used in the
code generation logic for diagnostic messages. In a follow-up CL, I
intend to move much of this code generation logic from
`package:analyzer` to `package:analyzer_utilities` so that the CFE can
make use of it without depending on `package:analyzer/src`. To make
that possible, these string extensions need to be moved into
`package:analyzer_utilities` too.

Change-Id: I6a6a6964e4648bdf6ced726a6a58ea9974876ae2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/447980
Commit-Queue: Paul Berry <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: stereotype441

pkg/analyzer/lib/src/utilities/extensions/string.dart

@@ -160,55 +160,6 @@ extension StringExtension on String {
     }
   }
 
-  /// Converts `SCREAMING_SNAKE_CASE` or `snake_case` to `camelCase`.
-  String toCamelCase() {
-    var parts = toLowerCase().split('_');
-    var buffer = StringBuffer();
-    var i = 0;
-    // Preserve initial '_'s
-    while (i < parts.length - 1 && parts[i].isEmpty) {
-      buffer.write('_');
-      ++i;
-    }
-    if (i < parts.length) {
-      // Convert first word to lower case
-      buffer.write(parts[i].toLowerCase());
-      ++i;
-      // Convert remaining words to initial upper case
-      while (i < parts.length) {
-        var part = parts[i];
-        if (part.isNotEmpty) {
-          buffer.write(part[0].toUpperCase());
-          buffer.write(part.substring(1));
-        }
-        ++i;
-      }
-    }
-    return buffer.toString();
-  }
-
-  /// Converts `SCREAMING_SNAKE_CASE` or `snake_case` to `PascalCase`.
-  String toPascalCase() {
-    var parts = toLowerCase().split('_');
-    var buffer = StringBuffer();
-    var i = 0;
-    // Preserve initial '_'s
-    while (i < parts.length - 1 && parts[i].isEmpty) {
-      buffer.write('_');
-      ++i;
-    }
-    // Convert words to initial upper case
-    while (i < parts.length) {
-      var part = parts[i];
-      if (part.isNotEmpty) {
-        buffer.write(part[0].toUpperCase());
-        buffer.write(part.substring(1));
-      }
-      ++i;
-    }
-    return buffer.toString();
-  }
-
   /// Converts `camelCase` / `PascalCase` to `SCREAMING_SNAKE_CASE`.
   /// Examples:
   ///  - camelCase        -> CAMEL_CASE

pkg/analyzer/test/generated/test_support.dart

@@ -12,7 +12,7 @@ import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/source/line_info.dart';
 import 'package:analyzer/source/source.dart';
 import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer/src/utilities/extensions/string.dart';
+import 'package:analyzer_utilities/extensions/string.dart';
 import 'package:test/test.dart';
 
 /// A description of a message that is expected to be reported with an error.

pkg/analyzer/test/src/utilities/extensions/string_test.dart

@@ -197,30 +197,6 @@ class StringExtensionTest {
     expect('01234'.removeSuffix('5'), isNull);
   }
 
-  void test_toCamelCase() {
-    expect('CAMEL_CASE'.toCamelCase(), 'camelCase');
-    expect('alreadyCamel_case'.toCamelCase(), 'alreadycamelCase');
-    expect('FOO_123_BAR'.toCamelCase(), 'foo123Bar');
-    expect('FOO'.toCamelCase(), 'foo');
-    expect('___'.toCamelCase(), '___');
-    expect(''.toCamelCase(), '');
-    expect('_FOO_BAR'.toCamelCase(), '_fooBar');
-    expect('FOO__BAR'.toCamelCase(), 'fooBar');
-    expect('FOO_BAR_'.toCamelCase(), 'fooBar');
-  }
-
-  void test_toPascalCase() {
-    expect('PASCAL_CASE'.toPascalCase(), 'PascalCase');
-    expect('AlreadyPascal_case'.toPascalCase(), 'AlreadypascalCase');
-    expect('FOO_123_BAR'.toPascalCase(), 'Foo123Bar');
-    expect('FOO'.toPascalCase(), 'Foo');
-    expect('___'.toPascalCase(), '___');
-    expect(''.toPascalCase(), '');
-    expect('_FOO_BAR'.toPascalCase(), '_FooBar');
-    expect('FOO__BAR'.toPascalCase(), 'FooBar');
-    expect('FOO_BAR_'.toPascalCase(), 'FooBar');
-  }
-
   void test_toScreamingSnake() {
     expect('camelCase'.toScreamingSnake(), 'CAMEL_CASE');
     expect('HTTPRequest'.toScreamingSnake(), 'HTTP_REQUEST');

pkg/analyzer/tool/messages/error_code_info.dart

@@ -5,8 +5,8 @@
 import 'dart:convert';
 import 'dart:io';
 
-import 'package:analyzer/src/utilities/extensions/string.dart';
 import 'package:analyzer_testing/package_root.dart' as pkg_root;
+import 'package:analyzer_utilities/extensions/string.dart';
 import 'package:analyzer_utilities/tools.dart';
 import 'package:path/path.dart';
 import 'package:yaml/yaml.dart' show loadYaml;

pkg/analyzer/tool/messages/generate.dart

@@ -19,8 +19,8 @@ library;
 import 'dart:convert';
 import 'dart:io';
 
-import 'package:analyzer/src/utilities/extensions/string.dart';
 import 'package:analyzer_testing/package_root.dart' as pkg_root;
+import 'package:analyzer_utilities/extensions/string.dart';
 import 'package:analyzer_utilities/tools.dart';
 import 'package:collection/collection.dart';
 import 'package:path/path.dart';

pkg/analyzer_utilities/lib/extensions/string.dart

@@ -0,0 +1,54 @@
+// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+extension StringExtension on String {
+  /// Converts `SCREAMING_SNAKE_CASE` or `snake_case` to `camelCase`.
+  String toCamelCase() {
+    var parts = toLowerCase().split('_');
+    var buffer = StringBuffer();
+    var i = 0;
+    // Preserve initial '_'s
+    while (i < parts.length - 1 && parts[i].isEmpty) {
+      buffer.write('_');
+      ++i;
+    }
+    if (i < parts.length) {
+      // Convert first word to lower case
+      buffer.write(parts[i].toLowerCase());
+      ++i;
+      // Convert remaining words to initial upper case
+      while (i < parts.length) {
+        var part = parts[i];
+        if (part.isNotEmpty) {
+          buffer.write(part[0].toUpperCase());
+          buffer.write(part.substring(1));
+        }
+        ++i;
+      }
+    }
+    return buffer.toString();
+  }
+
+  /// Converts `SCREAMING_SNAKE_CASE` or `snake_case` to `PascalCase`.
+  String toPascalCase() {
+    var parts = toLowerCase().split('_');
+    var buffer = StringBuffer();
+    var i = 0;
+    // Preserve initial '_'s
+    while (i < parts.length - 1 && parts[i].isEmpty) {
+      buffer.write('_');
+      ++i;
+    }
+    // Convert words to initial upper case
+    while (i < parts.length) {
+      var part = parts[i];
+      if (part.isNotEmpty) {
+        buffer.write(part[0].toUpperCase());
+        buffer.write(part.substring(1));
+      }
+      ++i;
+    }
+    return buffer.toString();
+  }
+}

pkg/analyzer_utilities/pubspec.yaml

@@ -20,3 +20,4 @@ dependencies:
 # Use 'any' constraints here; we get our versions from the DEPS file.
 dev_dependencies:
   lints: any
+  test_reflective_loader: any

pkg/analyzer_utilities/test/extensions/string_test.dart

@@ -0,0 +1,44 @@
+// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Conventions for tests written using `package:test_reflective_loader` aren't
+// compatible with the `non_constant_identifier_names` lint.
+// ignore_for_file: non_constant_identifier_names
+
+import 'package:analyzer_utilities/extensions/string.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+void main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(StringExtensionTest);
+  });
+}
+
+@reflectiveTest
+class StringExtensionTest {
+  void test_toCamelCase() {
+    expect('CAMEL_CASE'.toCamelCase(), 'camelCase');
+    expect('alreadyCamel_case'.toCamelCase(), 'alreadycamelCase');
+    expect('FOO_123_BAR'.toCamelCase(), 'foo123Bar');
+    expect('FOO'.toCamelCase(), 'foo');
+    expect('___'.toCamelCase(), '___');
+    expect(''.toCamelCase(), '');
+    expect('_FOO_BAR'.toCamelCase(), '_fooBar');
+    expect('FOO__BAR'.toCamelCase(), 'fooBar');
+    expect('FOO_BAR_'.toCamelCase(), 'fooBar');
+  }
+
+  void test_toPascalCase() {
+    expect('PASCAL_CASE'.toPascalCase(), 'PascalCase');
+    expect('AlreadyPascal_case'.toPascalCase(), 'AlreadypascalCase');
+    expect('FOO_123_BAR'.toPascalCase(), 'Foo123Bar');
+    expect('FOO'.toPascalCase(), 'Foo');
+    expect('___'.toPascalCase(), '___');
+    expect(''.toPascalCase(), '');
+    expect('_FOO_BAR'.toPascalCase(), '_FooBar');
+    expect('FOO__BAR'.toPascalCase(), 'FooBar');
+    expect('FOO_BAR_'.toPascalCase(), 'FooBar');
+  }
+}