Implicitly constrain barback to versions pub supports.

Implicitly constrain barback to versions pub supports.

BUG=https://code.google.com/p/dart/issues/detail?id=15345
R=nweiz@google.com

Committed: https://code.google.com/p/dart/source/detail?r=30923

[Bob Nystrom, 2013-12-04 20:50:03]

After this goes in and is released to the wild, I think it means we can start
publishing barback independently of the SDK.

[nweiz, 2013-12-04 22:30:42]

We should also be sure that pub doesn't consider the lockfile to be up-to-date
if it has a version of barback that doesn't match pub's internal constraint.

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
File sdk/lib/_internal/pub/lib/src/barback.dart (right):

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/barback.dart:43: final supportedVersion = new
Version(0, 10, 2);
As discussed offline, the patch version here should always be zero since patch
releases will maintain wire compatibility.

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
File sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart (right):

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart:604: if (name ==
"barback") {
We should probably only do this if the dependencies on the package are hosted
dependencies.

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart:608: }
Log a message about adding this constraint.

[Bob Nystrom, 2013-12-05 19:32:05]

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
File sdk/lib/_internal/pub/lib/src/barback.dart (right):

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/barback.dart:43: final supportedVersion = new
Version(0, 10, 2);
On 2013/12/04 22:30:42, nweiz wrote:
> As discussed offline, the patch version here should always be zero since patch
> releases will maintain wire compatibility.

Done.

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
File sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart (right):

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart:604: if (name ==
"barback") {
On 2013/12/04 22:30:42, nweiz wrote:
> We should probably only do this if the dependencies on the package are hosted
> dependencies.

I think it's useful to at least support path dependencies. Added a comment
explaining.

https://codereview.chromium.org/105473002/diff/20001/sdk/lib/_internal/pub/li...
sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart:608: }
On 2013/12/04 22:30:42, nweiz wrote:
> Log a message about adding this constraint.

Done.

[nweiz, 2013-12-05 20:32:38]

lgtm

[Bob Nystrom, 2013-12-05 23:39:12]

Committed patchset #3 manually as r30923 (presubmit successful).