Use a lockfile to persist Pub's installed version constellation.

utils/tests/pub/version_solver_test.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.
 
 #library('pub_update_test');
 
 #import('dart:io');
 #import('dart:isolate');
 
+#import('../../pub/lock_file.dart');
 #import('../../pub/package.dart');
 #import('../../pub/pubspec.dart');
 #import('../../pub/source.dart');
 #import('../../pub/source_registry.dart');
 #import('../../pub/utils.dart');
 #import('../../pub/version.dart');
 #import('../../pub/version_solver.dart');
 #import('../../../lib/unittest/unittest.dart');
 
 final noVersion = 'no version';
@@ skipping 101 matching lines @@
     'foo 1.2.3 from versionless': {
       'bar': '>=1.0.0'
     },
     'bar 1.1.0': {}
   }, result: {
     'myapp': '0.0.0',
     'foo': '1.2.3',
     'bar': '1.1.0'
   });
 
+  testResolve('with compatible locked dependency', {
+    'myapp 0.0.0': {
+      'foo': 'any'
+    },
+    'foo 1.0.0': { 'bar': '1.0.0' },
+    'foo 1.0.1': { 'bar': '1.0.1' },
+    'foo 1.0.2': { 'bar': '1.0.2' },
+    'bar 1.0.0': {},
+    'bar 1.0.1': {},
+    'bar 1.0.2': {}
+  }, lockfile: {
+    'foo': '1.0.1'
+  }, result: {
+    'myapp': '0.0.0',
+    'foo': '1.0.1',
+    'bar': '1.0.1'
+  });
+
+  testResolve('with incompatible locked dependency', {
+    'myapp 0.0.0': {
+      'foo': '>1.0.1'
+    },
+    'foo 1.0.0': { 'bar': '1.0.0' },
+    'foo 1.0.1': { 'bar': '1.0.1' },
+    'foo 1.0.2': { 'bar': '1.0.2' },
+    'bar 1.0.0': {},
+    'bar 1.0.1': {},
+    'bar 1.0.2': {}
+  }, lockfile: {
+    'foo': '1.0.1'
+  }, result: {
+    'myapp': '0.0.0',
+    'foo': '1.0.2',

[Jennifer Messerly, 2012/07/19 18:45:34]

so if the lockfile is incompatible, it just gets upgraded?

[nweiz, 2012/07/19 18:56:54]

Yes. This should only happen when the user modifies the pubspec, which
presumably means they want updated versions of their files.

[Jennifer Messerly, 2012/07/19 19:06:30]

Makes sense

+    'bar': '1.0.2'
+  });
+
+  testResolve('with unrelated locked dependency', {
+    'myapp 0.0.0': {
+      'foo': 'any'
+    },
+    'foo 1.0.0': { 'bar': '1.0.0' },
+    'foo 1.0.1': { 'bar': '1.0.1' },
+    'foo 1.0.2': { 'bar': '1.0.2' },
+    'bar 1.0.0': {},
+    'bar 1.0.1': {},
+    'bar 1.0.2': {},
+    'baz 1.0.0': {}
+  }, lockfile: {
+    'baz': '1.0.0'
+  }, result: {
+    'myapp': '0.0.0',
+    'foo': '1.0.2',
+    'bar': '1.0.2'
+  });
+
   testResolve('dependency back onto root package', {
     'myapp 1.0.0': {
       'foo': '1.0.0'
     },
     'foo 1.0.0': {
       'myapp': '>=1.0.0'
     }
   }, error: sourceMismatch);
 
   testResolve('no version that matches requirement', {
@@ skipping 78 matching lines @@
   }, error: couldNotSolve);
 
 // TODO(rnystrom): More stuff to test:
 // - Two packages depend on the same package, but from different sources. Should
 //   fail.
 // - Depending on a non-existent package.
 // - Test that only a certain number requests are sent to the mock source so we
 //   can keep track of server traffic.
 }
 
-testResolve(description, packages, [result, error]) {
+testResolve(description, packages, [lockfile, result, error]) {
   test(description, () {
     var sources = new SourceRegistry();
     source1 = new MockSource('mock1');
     source2 = new MockSource('mock2');
     versionlessSource = new MockVersionlessSource();
     sources.register(source1);
     sources.register(source2);
     sources.register(versionlessSource);
     sources.setDefault(source1.name);
 
@@ skipping 19 matching lines @@
       }
     });
 
     // Clean up the expectation.
     if (result != null) {
       result.forEach((name, version) {
         result[name] = new Version.parse(version);
       });
     }
 
+    var realLockFile = new LockFile.empty();
+    if (lockfile != null) {
+      lockfile.forEach((name, version) {
+        version = new Version.parse(version);
+        realLockFile.packages[name] = new PackageId(source1, version, name);
+      });
+    }
+
     // Resolve the versions.
-    var future = resolveVersions(sources, root);
+    var future = resolveVersions(sources, root, realLockFile);
 
     if (result != null) {
       expect(future, completion(predicate((actualResult) {
         for (var id in actualResult) {
           if (!result.containsKey(id.description)) return false;
           if (id.version != result.remove(id.description)) return false;
         }
         return result.isEmpty();
       }, description: 'packages to match $result')));
     } else if (error == noVersion) {
@@ skipping 113 matching lines @@
 Pair<String, Source> parseSource(String name) {
   var match = new RegExp(@"(.*) from (.*)").firstMatch(name);
   if (match == null) return new Pair<String, Source>(name, source1);
   switch (match[2]) {
   case 'mock1': return new Pair<String, Source>(match[1], source1);
   case 'mock2': return new Pair<String, Source>(match[1], source2);
   case 'versionless':
     return new Pair<String, Source>(match[1], versionlessSource);
   }
 }