Prefer Mercurial and Git over Subversion in discovering repository

Summary: `svn info` is the slowest command for discovering repository (up to 300 ms) and Subversion is probably the least used repository type with Arcanist. Let's discover it last.

Test Plan:
  $ arc lint --trace

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4039
Provide a method for getting Git SVN revision

Summary: I plan to use it in `save_lint.php`.

Test Plan:
  $api->getUnderlyingWorkingCopyRevision(); // In Git SVN repo

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4054
Improve getting Git author

Summary:
It has one more than source, see http://www.kernel.org/pub/software/scm/git/docs/git-commit-tree.html#_commit_information.
Also 'user.name' may not be set at all.
Also `git config` returns non-zero for non-existing value.

Test Plan:
  var_dump($api->getAuthor());

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4053
Add a very basic Scala (SBT) linter.

Summary:
SBT is the most common Scala buildsystem. This adds an extremely basic and
slightly horrible linter to check SBT's output for warnings and errors.

Test Plan:
Tested this with a Scala project I've been working on for some time.
It seemed relatively sane.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4064
Break arc land run() into smaller functions

Summary:
Refactor the arc land code into several
functions so it's easier to maintain. This is in
preparation for adding hg support to arc land
in my next commit.

Without this refactor, adding hg support makes the run()
function too big.

Test Plan:
Set up a git repo and clone with a branch scenario.
Example: https://secure.phabricator.com/P614
Ran and verified:
arc land
arc land --keep-branch
arc land --merge
arc land --merge --keep-branch
arc land --hold
arc land --revision <another phabricator rev>

Reviewers: epriestley

Reviewed By: epriestley

CC: dschleimer, sid0, aran, Korvin

Differential Revision: https://secure.phabricator.com/D4056
canRun should return false on scala linter instead of raising an exception

Summary:
This was causing the following error in environments that didnt have scala configured:

Some linters failed:
   - ArcanistScalaSBTLinter: ArcanistUsageException: This directory does not appear to be maintained by SBT, as we can't seem to find a working build file (project/Build.scala or build.sbt).

Test Plan: .

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4070
Allow setting lint cache granularity

Summary:
We can add `GRANULARITY_DIRECTORY` and `GRANULARITY_REPOSITORY` later.
Repository granularity may use current commit + changes.
Directory would need to use hashes of all files in dir which would be quite expensive.

Test Plan:
  $ echo '<?php class A extends B {}' > A.php
  $ arc lint --cache 1
  $ arc lint --cache 1
  $ echo '<?php class B {}' > B.php
  $ arc lint --cache 1
  $ arc lint --cache 1
  $ rm B.php
  $ arc lint --cache 1
  $ arc lint --cache 1

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4021
Restore order of operations after D4056

Summary:
See discussion in D4056. In `findRevision()` we call `loadWorkingCopyDifferentialRevisions()`. However, this method depends upon the state of the working copy, because the end of the commit range it examines is HEAD. Prior to D4056 we checked out the target branch before calling `findRevision()`; after D4056 we call it earlier.

This isn't problematic in the `arc land` case, but in the `arc land <branch>` case it means we may fail to identify a revision, or identify the wrong revision, because HEAD isn't where we expect it to be.

Instead, unconditionally check out the target branch before finding the revision.

See <http://dl.dropbox.com/u/116385/Slingshot/Pictures/Screen%20Shot%202012-12-03%20at%203.43.45%20PM.png> for a transcript of the issue.

Test Plan: Reproduced issue as per link above. Ran `arc land --keep-branch --hold somebranch` successfully after this patch.

Reviewers: DurhamGoode, zeeg

Reviewed By: DurhamGoode

CC: aran

Differential Revision: https://secure.phabricator.com/D4072
Introduce `arc lint --only-new 1`

Test Plan:
  $ arc lint src/workflow/ArcanistLintWorkflow.php
  $ arc lint --only-new 1 src/workflow/ArcanistLintWorkflow.php

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2038

Differential Revision: https://secure.phabricator.com/D3934
Add hg support for arc land

Summary:
Makes arc land support hg repositories. Both bookmarks and named branches can be landed.  For the most part all the arc land options work, but there are a few caveats:

- bookmarks can only be landed on bookmarks
- branches can only be landed on branches
- landing a named branch with --merge creates a commit to close the branch before the merge.
- since mercurial doesn't start with a default master bookmark, landing a bookmark requires specifying --onto or setting arc.land.onto.default

Test Plan:
Tested arc land with all permutations of --merge, --keep-branch on both bookmark branches and named branches.  Also tested --hold, --revision, --onto, --remote.

See https://secure.phabricator.com/P619

Also tested git arc land with --merge and --keep-branch.

Reviewers: dschleimer, sid0, epriestley, bos

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4068
Bump Conduit client version number

Summary: Should have been part of D3934.

Test Plan:
  $ arc diff

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4076
Fix a fatal for git uncommitted changes in new arc projects

Summary:
If you run `arc diff` in a repository which:

  - has uncommitted or untracked changes; and
  - has a .arcconfig with a never-before-seen project ID;
  - we fatal: http://pastebin.com/raw.php?i=ykpfr4MT

This patch is a bit iffy, open to alternatives. The "right" patch is probably an `arcanistproject.query` which behaves more sensibly.

I return array() directly since we'll later create the project.

Test Plan: Ran `arc diff` in a repository with untracked files or uncommitted changes and a new project ID.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4057
Introduce "arc diff --plan-changes"

Summary:
Allow authors to publish a new or updated revision to Phabricator
without requesting code reviews. The revision will have status
"Needs Revision" instead of "Needs Review".

In order to avoid a change of Conduit API, this is done by adding
a comment with the "plan changes" action immediately after the
revision is published.

Test Plan:
Using my local repository, run "./bin/arc diff --plan-changes"
Check the resulting diff in Phabricator.

Reviewers: vrana

Reviewed By: vrana

CC: aran, epriestley

Maniphest Tasks: T2024

Differential Revision: https://secure.phabricator.com/D4084
Quote author parameter

Summary:
Fixes the exception:

  Exception
  Command 'git commit -a --author=Whatever Long Name <whatever@email.com> -F -' failed with error #1

Test Plan: Tested with full git name

Reviewers: epriestley, aurelijus

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3979
Remove ArcanistSubversionAPI::hasMergeConflicts()

Summary: No callsites, redundant with getMergeConflicts().

Test Plan: Grepped for callsites.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4093