Dispatch event after collecting changes in diff

Summary:
FB currently starts Sandcastle push before starting the diff workflow.
If `arc diff` commits something then we need to restart the push.
I want to avoid this by starting the push after commit.

Test Plan: Will test after implementing the listener.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4785
Lint dynamic string usage in parameters treated as safe

Summary:
This disallows code like this:

  $cmd = 'ls';
  execx($cmd);

But I guess it's not that big deal?

Test Plan: Linted whole Arcanist and Phabricator codebases, most parts looks fixable.

Reviewers: epriestley

CC: nh, aran, Korvin

Differential Revision: https://secure.phabricator.com/D4794
Fix dynamic string usage as safe input

Summary: This fixes some real issues.

Test Plan:
  $ arc lint

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin, btrahan

Differential Revision: https://secure.phabricator.com/D4795
Fix dynamic string usage as safe input

Summary: I somehow missed it.

Test Plan: Sent this diff by different copy of Arcanist.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4800
Fix dynamic string usage as safe input

Test Plan: Copied the code in a script, changed `phutil_passthru()` to `echo csprintf()` and ran it.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4805
Allow `arc diff` and similar to run on systems with no `git`

Summary:
We assume `git` is available now, but should not. Specifically, if a user runs a working copy operation like `arc list` in an SVN working copy without `git` available, they get this error: P707

We interpret git errors very narrowly; be more liberal in how we interpret them. This assumes users working with `git` will have a functional `git`, but this seems like a reasonable assumption and lets us remove some error text matching code.

Test Plan: Changed `git` to `girt`, ran `arc list`, saw a reasonable exception. Changed back to `git`, saw git detected.

Reviewers: btrahan, vrana

Reviewed By: vrana

CC: svemir, aran

Differential Revision: https://secure.phabricator.com/D4804
Implement hook for checking switch lint

Summary:
We want to use it for `yield` and `invariant_violation()` which throws.
Having node instead of token would be better but this would be enough.

Test Plan: Implemented a hook in FB repo and added a test case there.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4821
Record commit email information from `arc`

Summary:
Record author email information in `arc diff`, so we can recreate it in `arc patch` and elsewhere without creating any kind of email exposure issues.

In Mercurial, we currently store the whole string ("username <email@domain.com>"). Make this consistent with Git.

Test Plan: Created git and hg diffs, saw authorEmail populated.

Reviewers: btrahan, edward, vrana

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D4825
Make "arc patch" read `authorName` and `authorEmail`

Summary: If provided, have `arc patch` use `authorName` / `authorEmail`. This simplifies handling and makes patches more portable between version control systems (previously, information was generated in the diff's VCS, regardless of which VCS it was being applied to).

Test Plan: Created a diff with author `derp <derp@derp.com>`, ran `arc patch --diff x`, got a local commit with that author.

Reviewers: btrahan, edward, vrana

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D4827
Improve error message for phutil missing symbols

Summary: This is fairly confusing. Make the error message suggest the common remedy (update libphutil).

Test Plan: Eyeballed it.

Reviewers: Afaque_Hussain, btrahan, vrana

Reviewed By: Afaque_Hussain

CC: aran

Differential Revision: https://secure.phabricator.com/D4834
Restore kept branch after landing

Test Plan: Ran it separately.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4846
Upload binary files diffs in parallel

Summary: Makes sense after D2471.

Test Plan:
Swapped two binary files, ran `arc diff --only`.
Saw time 3.797 s instead of 4.361 s.

Changed `file.upload` to `file.uploa`, saw proper error.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4847
Improve performance of mercurial arc diff

Summary:
arc diff on large mercurial repos was taking 14 seconds just to get
to the commit message prompt.  With these optimizations it takes 4.

- "ancestor(.) - ancestor(XYZ)" is expensive because it has to build the
entire 400000+ revision history for both.  "XYZ::. - XYZ" is much cheaper
because it only looks at the revisions between XYZ and the working directory.

- "hg outgoing" has to talk to the server, which is slow.  "hg log -r draft()"
gives us the same information and is much cheaper.  We fall back to 'outgoing'
on older versions of mercurial.

Of the remaining 4 seconds, 2.5 are spent in 'hg status', which is a bit harder
improve.

Test Plan: Ran arc diff on our hg repo. Verified it ran faster and the diff was created.

Reviewers: epriestley, sid0, bos, dschleimer

Reviewed By: epriestley

CC: aran, Korvin, tido

Differential Revision: https://secure.phabricator.com/D4838
Make 'arc diff X' in mercurial match git by using the GCA of X as the base

Summary:
Previously 'arc diff X' with mercurial meant to use X as the base
to diff against.  Now it means use gca(X,working directory) as the base to
diff against.  This matches the git behavior.

Test Plan:
Ran 'arc diff master' on a repo where master was ahead of the feature branch.
Verified that the diff result included only the diffs in the feature branch.

Reviewers: epriestley, sid0, bos, dschleimer

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4865
Display other locations of Reused lint errors

Summary: It's not trivial to find them inside 700+ lines long functions.

Test Plan:
Linted `reused-iterators.lint-test` renamed to `_.php`, saw other locations.
Repeated for `reused-local.lint-test`.
Repeated for `duplicate-key-in-array.lint-test`.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4871
Add lint warnings about use of phutil_render_tag and javelin_render_tag

Summary: Raise deprecation warnings for these methods. I won't commit this until the phutil_tag branch merges.

Test Plan: Unit tests.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4770
Support arc diff --edit under hg

Summary: T1571

Test Plan: epriestley says it works

Reviewers: epriestley

Reviewed By: epriestley

CC: kwadwon, aran, Korvin

Differential Revision: https://secure.phabricator.com/D4883
Deprecate phutil_escape_html()

Summary:
My original idea was to return safe HTML from this function.
But we are down to 20 occurrences in Phabricator and you shouldn't need this function in safe HTML world at all.

Test Plan:
  $ arc lint src/applications/audit/controller/PhabricatorAuditListController.php

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4890
Minor, fix an exception variable.

Auditors: DurhamGoode
Delete license linters.

Summary: Remove all references to ArcanistLicenseLinter and ArcanistApacheLicenseLinter.

Test Plan: Rerun the linter and ensure nothing is broken.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4901