Don't allow pre-release versions of the max in "<" constraints.

sdk/lib/_internal/pub/lib/src/version.dart

 // Copyright (c) 2012, 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.
 
 /// Handles version numbers, following the [Semantic Versioning][semver] spec.
 ///
 /// [semver]: http://semver.org/
 library pub.version;
 
 import 'dart:math';
@@ skipping 456 matching lines @@
            includeMin == other.includeMin &&
            includeMax == other.includeMax;
   }
 
   bool get isEmpty => false;
 
   bool get isAny => min == null && max == null;
 
   /// Tests if [other] matches falls within this version range.
   bool allows(Version other) {
-    if (min != null && other < min) return false;
-    if (min != null && !includeMin && other == min) return false;
-    if (max != null && other > max) return false;
-    if (max != null && !includeMax && other == max) return false;
+    if (min != null) {
+      if (other < min) return false;
+      if (!includeMin && other == min) return false;
+    }
+
+    if (max != null) {
+      if (other > max) return false;
+      if (!includeMax && other == max) return false;
+
+      // If the max isn't itself a pre-release, don't allow any pre-release
+      // versions of the max.
+      //
+      // See: https://www.npmjs.org/doc/misc/semver.html
+      if (!includeMax &&
+          !max.isPreRelease && other.isPreRelease &&
+          other.major == max.major && other.minor == max.minor &&
+          other.patch == max.patch) {
+        return false;
+      }
+    }
+
     return true;
   }
 
   VersionConstraint intersect(VersionConstraint other) {
     if (other.isEmpty) return other;
 
     // A range and a Version just yields the version if it's in the range.
     if (other is Version) {
       return allows(other) ? other : VersionConstraint.empty;
     }
@@ skipping 75 matching lines @@
 
 class _EmptyVersion implements VersionConstraint {
   const _EmptyVersion();
 
   bool get isEmpty => true;
   bool get isAny => false;
   bool allows(Version other) => false;
   VersionConstraint intersect(VersionConstraint other) => this;
   String toString() => '<empty>';
 }