Handle long relative path dependencies better.

sdk/lib/_internal/pub/test/build/handles_long_paths_test.dart

+// Copyright (c) 2013, 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 'package:scheduled_test/scheduled_test.dart';
+
+import 'package:path/path.dart' as path;
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+
+main() {
+  initConfig();
+
+  // This is a regression test for dartbug.com/14442.
+  //
+  // If you have a long chain of path dependencies with long relative paths,
+  // you can end up with a combined path that is longer than the OS can handle.
+  // For example, the path that revealed this bug was:
+  //
+  // C:\jenkins-slave\workspace\mSEE-Dev\ozone\dart\portfolio-manager\src\main\
+  // portfolio-manager\..\..\..\..\portfolio-common\src\main\portfolio-common\
+  // ../../../../dart-visualization/src/main/dart-visualization\lib\src\vega\
+  // data\transform\visual
+  //
+  // This test ensures that we're normalizing at some point before we throw the
+  // path at the OS to choke on.
+
+  integration("handles long relative paths", () {
+    // Dart2js can take a long time to compile dart code, so we increase the
+    // timeout to cope with that.
+    currentSchedule.timeout *= 3;
+
+    d.dir("some_long_dependency_name", [
+      d.libPubspec("foo", "0.0.1"),
+      d.dir("asset", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
+
+    // Build a 2,800 character (non-canonicalized) path.
+    var longPath = "";
+    for (var i = 0; i < 100; i++)
+    {
+      longPath = path.join(longPath, "..", "some_long_dependency_name");
+    }
+
+    d.dir(appPath, [
+      d.appPubspec({
+        "foo": {"path": longPath}
+      }),
+      d.dir("web", [
+        d.file("index.html", "html"),
+      ])
+    ]).create();
+
+    schedulePub(args: ["build"],
+        output: new RegExp(r"Built 2 files!"),
+        exitCode: 0);
+
+    d.dir(appPath, [
+      d.dir('build', [
+        d.file("index.html", "html"),
+        d.dir('assets', [
+          d.dir('foo', [
+            d.file('foo.txt', 'foo')
+          ])
+        ])
+      ])
+    ]).validate();
+  });
+}