Backjump on a source or description mismatch.

sdk/lib/_internal/pub/test/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:async';
 import 'dart:io';
 
 import 'package:unittest/unittest.dart';
 
 import '../lib/src/lock_file.dart';
+import '../lib/src/log.dart' as log;
 import '../lib/src/package.dart';
 import '../lib/src/pubspec.dart';
 import '../lib/src/sdk.dart' as sdk;
 import '../lib/src/source.dart';
 import '../lib/src/source_registry.dart';
 import '../lib/src/system_cache.dart';
 import '../lib/src/utils.dart';
 import '../lib/src/version.dart';
 import '../lib/src/solver/version_solver.dart';
 import 'test_pub.dart';
 
 MockSource source1;
 MockSource source2;
 
 main() {
   initConfig();
 
+  // Uncomment this to debug failing tests.
+  // log.showSolver();
+
   // Since this test isn't run from the SDK, it can't find the "version" file
   // to load. Instead, just manually inject a version.
   sdk.version = new Version(1, 2, 3);
 
   group('basic graph', basicGraph);
   group('with lockfile', withLockFile);
   group('root dependency', rootDependency);
   group('dev dependency', devDependency);
   group('unsolvable', unsolvable);
   group('backtracking', backtracking);
@@ skipping 437 matching lines @@
     'b 2.0.0': {},
     'b 3.0.0': {},
     'c 1.0.0': {},
   }, result: {
     'myapp from root': '0.0.0',
     'a': '1.0.0',
     'b': '3.0.0',
     'c': '1.0.0'
   }, maxTries: 2);
 
+  // Tests that the backjumper will jump past unrelated selections when a
+  // source conflict occurs. This test selects, in order:
+  // - myapp -> a
+  // - myapp -> b
+  // - myapp -> c (1 of 5)
+  // - b -> a
+  // It selects a and b first because they have fewer versions than c. It
+  // traverses b's dependency on a after selecting a version of c because
+  // dependencies are traversed breadth-first (all of myapps's immediate deps
+  // before any other their deps).
+  //
+  // This means it doesn't discover the source conflict until after selecting
+  // c. When that happens, it should backjump past c instead of trying older
+  // versions of it since they aren't related to the conflict.
+  testResolve('backjump to conflicting source', {
+    'myapp 0.0.0': {
+      'a': 'any',
+      'b': 'any',
+      'c': 'any'
+    },
+    'a 1.0.0': {},
+    'a 1.0.0 from mock2': {},
+    'b 1.0.0': {
+      'a from mock2': 'any'
+    },
+    'c 1.0.0': {},
+    'c 2.0.0': {},
+    'c 3.0.0': {},
+    'c 4.0.0': {},
+    'c 5.0.0': {},
+  }, error: sourceMismatch('myapp', 'b'), maxTries: 1);
+
+  // Like the above test, but for a conflicting description.
+  testResolve('backjump to conflicting description', {
+    'myapp 0.0.0': {
+      'a-x': 'any',
+      'b': 'any',
+      'c': 'any'
+    },
+    'a-x 1.0.0': {},
+    'a-y 1.0.0': {},
+    'b 1.0.0': {
+      'a-y': 'any'
+    },
+    'c 1.0.0': {},
+    'c 2.0.0': {},
+    'c 3.0.0': {},
+    'c 4.0.0': {},
+    'c 5.0.0': {},
+  }, error: descriptionMismatch('myapp', 'b'), maxTries: 1);
+
   // Dependencies are ordered so that packages with fewer versions are tried
   // first. Here, there are two valid solutions (either a or b must be
   // downgraded once). The chosen one depends on which dep is traversed first.
   // Since b has fewer versions, it will be traversed first, which means a will
   // come later. Since later selections are revised first, a gets downgraded.
   testResolve('traverse into package with fewer versions first', {
     'myapp 0.0.0': {
       'a': 'any',
       'b': 'any'
     },
@@ skipping 115 matching lines @@
     'bar': '2.0.0'
   }, maxTries: 3);
 
   testResolve('ignores SDK constraints on bleeding edge', {
     'myapp 0.0.0': {'sdk': badVersion }
   }, result: {
     'myapp from root': '0.0.0'
   }, useBleedingEdgeSdkVersion: true);
 }
 
-testResolve(description, packages,
-            {lockfile, result, FailMatcherBuilder error, int maxTries,
+testResolve(description, packages, {
+             lockfile, result, FailMatcherBuilder error, int maxTries,
+             bool useBleedingEdgeSdkVersion}) {
+  _testResolve(test, description, packages, lockfile: lockfile, result: result,
+      error: error, maxTries: maxTries,
+      useBleedingEdgeSdkVersion: useBleedingEdgeSdkVersion);
+}
+
+solo_testResolve(description, packages, {
+             lockfile, result, FailMatcherBuilder error, int maxTries,
+             bool useBleedingEdgeSdkVersion}) {
+  log.showSolver();
+  _testResolve(solo_test, description, packages, lockfile: lockfile,
+      result: result, error: error, maxTries: maxTries,
+      useBleedingEdgeSdkVersion: useBleedingEdgeSdkVersion);
+}
+
+_testResolve(void testFn(String description, Function body),
+             description, packages, {
+             lockfile, result, FailMatcherBuilder error, int maxTries,
              bool useBleedingEdgeSdkVersion}) {
   if (maxTries == null) maxTries = 1;
   if (useBleedingEdgeSdkVersion == null) useBleedingEdgeSdkVersion = false;
 
-  test(description, () {
+  testFn(description, () {
     var cache = new SystemCache('.');
     source1 = new MockSource('mock1');
     source2 = new MockSource('mock2');
     cache.register(source1);
     cache.register(source2);
     cache.sources.setDefault(source1.name);
 
     // Build the test package graph.
     var root;
     packages.forEach((nameVersion, dependencies) {
@@ skipping 350 matching lines @@
   };
 
   var match = new RegExp(r"(.*) from (.*)").firstMatch(description);
   if (match != null) {
     name = match[1];
     source = sourceNames[match[2]];
   }
 
   callback(isDev, name, source);
 }