[pub_semver] Discourage modification of properties intended to be unmodifiable

pkgs/pub_semver/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 2.2.0-wip
+
+- Clarify the `preRelease` and `build` properties of `Version`
+  return unmodifiable lists.
+
 ## 2.1.5
 
 - Require Dart `3.4.0`.

pkgs/pub_semver/lib/src/version.dart

@@ -70,13 +70,17 @@ class Version implements VersionConstraint, VersionRange {
   /// This is split into a list of components, each of which may be either a
   /// string or a non-negative integer. It may also be empty, indicating that
   /// this version has no pre-release identifier.
+  ///
+  /// The returned list is unmodifiable.
   final List<Object> preRelease;
 
   /// The build identifier: "foo" in "1.2.3+foo".
   ///
   /// This is split into a list of components, each of which may be either a
   /// string or a non-negative integer. It may also be empty, indicating that
   /// this version has no build identifier.
+  ///
+  /// The returned list is unmodifiable.
   final List<Object> build;
 
   /// The original string representation of the version number.
@@ -96,8 +100,10 @@ class Version implements VersionConstraint, VersionRange {
 
   Version._(this.major, this.minor, this.patch, String? preRelease,
       String? build, this._text)
-      : preRelease = preRelease == null ? <Object>[] : _splitParts(preRelease),
-        build = build == null ? [] : _splitParts(build) {
+      : preRelease = preRelease == null || preRelease.isEmpty
+            ? const []
+            : _splitParts(preRelease),
+        build = build == null || build.isEmpty ? const [] : _splitParts(build) {
     if (major < 0) throw ArgumentError('Major version must be non-negative.');
     if (minor < 0) throw ArgumentError('Minor version must be non-negative.');
     if (patch < 0) throw ArgumentError('Patch version must be non-negative.');
@@ -160,7 +166,7 @@ class Version implements VersionConstraint, VersionRange {
           // Return an integer part if possible, otherwise return the string
           // as-is
           int.tryParse(part) ?? part)
-      .toList();
+      .toList(growable: false);
 
   @override
   bool operator ==(Object other) =>

pkgs/pub_semver/pubspec.yaml

@@ -1,5 +1,5 @@
 name: pub_semver
-version: 2.1.5
+version: 2.2.0-wip
 description: >-
   Versions and version constraints implementing pub's versioning policy. This
   is very similar to vanilla semver, with a few corner cases.