This folds the distinction between "resolved" and "unresolved"
descriptions into the distinction between PackageIds and PackageRefs. In
other words, all PackageIds now have resolved descriptions and all
PackageRefs now have unresolved descriptions. This makes it easier to
track which descriptions are resolved and express resolution constraints
via the type system.

This also restricts the creation of PackageRefs and PackageIds to source
classes, which helps ensure that the description format—which is an
implementation detail—doesn't leak into surrounding code.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1528523003 .

Previously these names were only disallowed when publishing, but now the
package config format requires that we be more stringent about them.

Closes #1361

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1493463002 .

We didn't properly check for no sources in a dependency, which caused a
crash for some invalid pubspecs.

Closes #1348

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1417993002 .

* Normalize paths before they're passed to dart2js. It handles "." and
  ".." path components poorly.

* Ensure that paths emitted by list-package-dirs are always absolute and
  normalized for backwards-compatibility with the existing protocol.

* Make Package.listFiles work for an in-memory package.

* Fix an error message expectation in packages_file_test.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1228683003 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1101343004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@45508 260f80e4-7a28-3924-810f-c04153c831b5

We were validating that the dependencies and dev_dependencies had no overlap
whenever we accessed [Pubspec.dependencies], but this meant that we had to parse
the dev_dependencies even if they were going unused. If that parse failed, it
could stop an entire "pub get" from working. Now we only do this validation when
[Pubspec.devDependencies] is accessed.

This also fixes a bug in where, if a pubspec from outside the filesystem (e.g. a
hosted dependency) has a relative path dependency, [PathSource.parseDescription]
would crash. Although this shouldn't happen since we don't parse the dev
dependencies anymore, [PathSource] will now handle it more gracefully if it
does.

Finally, this also works around an async_await bug that was causing stack traces
to be truncated.

R=rnystrom@google.com
BUG=22194

Review URL: https://codereview.chromium.org//887483002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@43267 260f80e4-7a28-3924-810f-c04153c831b5

BUG= https://code.google.com/p/dart/issues/detail?id=21229

Example:
$ cat pubspec.yaml
name: Name
description: A sample command-line application
version: 1.0

$ pub get
Resolving dependencies...
Error on line 3, column 10 of pubspec.yaml: "version" field must have three numeric components: major, minor, and patch. Instead of "1.0", consider "1.0.0".
version: 1.0
         ^^^

also

$ cat pubspec.yaml
name: Name
description: A sample command-line application
version: 1

$ pub get
Resolving dependencies...
Error on line 3, column 10 of pubspec.yaml: "version" field must have three numeric components: major, minor, and patch. Instead of "1", consider "1.0.0".
version: 1
         ^

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//632483002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@40971 260f80e4-7a28-3924-810f-c04153c831b5

R=nweiz@google.com

Review URL: https://codereview.chromium.org//602253002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@40849 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=18539
R=nweiz@google.com

Review URL: https://codereview.chromium.org//566093003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@40471 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=20287

Review URL: https://codereview.chromium.org//494803003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39429 260f80e4-7a28-3924-810f-c04153c831b5

R=nweiz@google.com

Review URL: https://codereview.chromium.org//463203002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39183 260f80e4-7a28-3924-810f-c04153c831b5

RELNOTE=Pubspecs can have a "publishTo" field which is either a URL to
  specify the default server that publishing should use or "none" to
  specify that the package is private and cannot be published.
BUG=https://code.google.com/p/dart/issues/detail?id=20046
R=nweiz@google.com

Review URL: https://codereview.chromium.org//417043005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38880 260f80e4-7a28-3924-810f-c04153c831b5

BUG=20103
R=blois@google.com

Review URL: https://codereview.chromium.org//417023002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38565 260f80e4-7a28-3924-810f-c04153c831b5

R=efortuna@google.com, rnystrom@google.com, sigmund@google.com
BUG=19930

Review URL: https://codereview.chromium.org//401753002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38526 260f80e4-7a28-3924-810f-c04153c831b5

I also cleaned up a bunch of unused imports.

BUG=https://code.google.com/p/dart/issues/detail?id=20067
R=nweiz@google.com

Review URL: https://codereview.chromium.org//391363004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38352 260f80e4-7a28-3924-810f-c04153c831b5

This change does three things:
* Splits out a WrappedException class from ApplicationException.
* Uses fail() pervasively rather than new ApplicationException() everywhere.
* Moves exception classes from utils.dart to exceptions.dart.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//354663008

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37713 260f80e4-7a28-3924-810f-c04153c831b5

This uses the source spans exposed by the yaml package to associate pubspec
errors visually with the section of the pubspec that caused them.

R=rnystrom@google.com
BUG=14999

Review URL: https://codereview.chromium.org//351703004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37675 260f80e4-7a28-3924-810f-c04153c831b5

Previously, two transformers from the same library but with different
configuration was considered completely different from one another. This was not
only inefficient but incorrect: it meant that a transformer could be loaded with
the wrong code.

R=rnystrom@google.com
BUG=19261

Review URL: https://codereview.chromium.org//344673002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37511 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=10582
R=nweiz@google.com

Review URL: https://codereview.chromium.org//344493003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37464 260f80e4-7a28-3924-810f-c04153c831b5

Also release yaml 1.0.0.

R=efortuna@google.com, rnystrom@google.com, sigmund@google.com

Review URL: https://codereview.chromium.org//302313007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@36937 260f80e4-7a28-3924-810f-c04153c831b5

R=nweiz@google.com

Review URL: https://codereview.chromium.org//243683002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@35344 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=18278

Review URL: https://codereview.chromium.org//241403002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@35149 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
TBR

Review URL: https://codereview.chromium.org//199583004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@33681 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=17213

Review URL: https://codereview.chromium.org//197463010

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@33677 260f80e4-7a28-3924-810f-c04153c831b5

* missing returns
* unused imports

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//184823012

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@33298 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=14594
R=nweiz@google.com

Review URL: https://codereview.chromium.org//169223010

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@33089 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=15841
R=nweiz@google.com

Review URL: https://codereview.chromium.org//164753002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@32681 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=14664

Review URL: https://codereview.chromium.org//133843006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@31755 260f80e4-7a28-3924-810f-c04153c831b5

- Parse them in pubspec.
- Pass them to solver.
- Warn when they are used.
- Error on publish.

BUG=https://code.google.com/p/dart/issues/detail?id=8566
R=nweiz@google.com

Review URL: https://codereview.chromium.org//74013007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@30376 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=14636

Review URL: https://codereview.chromium.org//59383009

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@30007 260f80e4-7a28-3924-810f-c04153c831b5

If the user specifies a transformer named "package_name", pub will now prefer
"lib/transformer.dart" (if it exists) to "lib/package_name.dart".

BUG=13256
R=alanknight@google.com

Review URL: https://codereview.chromium.org//29603004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@29035 260f80e4-7a28-3924-810f-c04153c831b5

BUG=
R=nweiz@google.com

Review URL: https://codereview.chromium.org//23702061

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@27977 260f80e4-7a28-3924-810f-c04153c831b5

The user-visible effect of this is to make operations that only look at part of
a pubspec work if other parts of the pubspec are somehow invalid. This is
particularly important for the following scenario:

1. We release a version of pub in SDK 1.0.0 that parses pubspec field "foo" as
   an integer.

2. Sally uploads version 0.1.0 of her package, libsally.

3. We release a new version of pub in SDK 1.1.0 that supports strings in "foo".

4. Sally uploads libsally 0.2.0, which uses a string in "foo". The new version
   of libsally has an SDK constraint of ">= 1.1.0", since it uses the new "foo"
   feature.

5. Tom is using SDK 1.0.0 and runs "pub install" in a package that depends on
   libsally.

Everyone's done everything right here; we made a backwards-compatible pubspec
change, Sally chose the correct SDK constraint, and Tom has a dependency on a
package that has a compatible version available.

However, prior to this change, Tom's "pub install" would crash. His outdated
version of pub would try and fail to parse libsally 0.2.0's "foo" field, and his
version resolution would crash. With this change, it will only attempt to parse
the SDK constraint portion of Sally's pubspec, and ignore anything else it
doesn't understand.

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//24246002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@27784 260f80e4-7a28-3924-810f-c04153c831b5

This also requires that transformer plugins define an [asPlugin] named
constructor in order to be loaded as plugins.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//23522029

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@27444 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//23924006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@27355 260f80e4-7a28-3924-810f-c04153c831b5

This is still missing some functionality, most notably the ability for
a transformer to import transformed code.

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//23625002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@27085 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=12300
R=nweiz@google.com

Review URL: https://codereview.chromium.org//22825024

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@26543 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=11046
R=nweiz@google.com

Review URL: https://codereview.chromium.org//23295025

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@26541 260f80e4-7a28-3924-810f-c04153c831b5

R=ajohnsen@google.com

Review URL: https://codereview.chromium.org//18356011

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@24964 260f80e4-7a28-3924-810f-c04153c831b5

R=nweiz@google.com

Review URL: https://codereview.chromium.org//18143002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@24555 260f80e4-7a28-3924-810f-c04153c831b5