Fix SDK constraints in lockfiles.

test/must_pub_get_test.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:pub/src/exit_codes.dart' as exit_codes;
 import 'package:pub/src/io.dart';
@@ skipping 334 matching lines @@
           d.appPubspec({"foo": "1.0.0"})
         ]).create();
 
         pubGet();
 
         _touch("pubspec.lock");
       });
 
       _runsSuccessfully();
     });
+
+    group("an overridden dependency's SDK constraint is unmatched", () {
+      setUp(() {
+        globalPackageServer.add((builder) {
+          builder.serve("bar", "1.0.0", pubspec: {
+            "environment": {"sdk": "0.0.0-fake"}
+          });
+        });
+
+        d.dir(appPath, [
+          d.pubspec({
+            "name": "myapp",
+            "dependency_overrides": {"bar": "1.0.0"}
+          })
+        ]).create();
+
+        pubGet();
+
+        _touch("pubspec.lock");
+      });
+
+      _runsSuccessfully();
+    });
   });
 }
 
 /// Runs every command that care about the world being up-to-date, and asserts
 /// that it prints [message] as part of its error.
 void _requiresPubGet(String message) {
   for (var command in ["build", "serve", "run", "deps"]) {
     integration("for pub $command", () {
       var args = [command];
       if (command == "run") args.add("script");
@@ skipping 51 matching lines @@
 void _touch(String path) {
   schedule(() async {
     // Delay a bit to make sure the modification times are noticeably different.
     // 1s seems to be the finest granularity that dart:io reports.
     await new Future.delayed(new Duration(seconds: 1));
 
     path = p.join(sandboxDir, "myapp", path);
     touch(path);
   }, "touching $path");
 }