Bug 1512487 - Part 1: Allow lints to inspect part of the build environment. r=ahal

This allows lints to "condition" themselves on having a build
environment or a specific build application.  It also adds the "name"
parameter, so that setup functions can be shared across lints.

`MozbuildObject` cannot be used as parameters to functions distributed
via multiprocessing, since they cannot be pickled (due, currently, to
internal terminal handles).  Therefore we extract just a few key
parts of the environment to expose.

Differential Revision: https://phabricator.services.mozilla.com/D35274

--HG--
extra : moz-landing-system : lando

python/mozlint/mozlint/roller.py

@@ -4,6 +4,7 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
+import copy
 import os
 import signal
 import sys
@@ -134,7 +135,9 @@ class LintRoller(object):
                 continue
 
             try:
-                res = findobject(linter['setup'])(**self.lintargs)
+                setupargs = copy.deepcopy(self.lintargs)
+                setupargs['name'] = linter['name']
+                res = findobject(linter['setup'])(**setupargs)
             except Exception:
                 traceback.print_exc()
                 res = 1

tools/lint/mach_commands.py

@@ -5,9 +5,11 @@
 from __future__ import absolute_import, print_function, unicode_literals
 
 import argparse
+import copy
 import os
 
 from mozbuild.base import (
+    BuildEnvironmentNotFoundException,
     MachCommandBase,
 )
 
@@ -58,6 +60,15 @@ class MachCommands(MachCommandBase):
         self._activate_virtualenv()
         from mozlint import cli, parser
 
+        try:
+            buildargs = {}
+            buildargs['substs'] = copy.deepcopy(dict(self.substs))
+            buildargs['defines'] = copy.deepcopy(dict(self.defines))
+            buildargs['topobjdir'] = self.topobjdir
+            lintargs.update(buildargs)
+        except BuildEnvironmentNotFoundException:
+            pass
+
         lintargs.setdefault('root', self.topsrcdir)
         lintargs['exclude'] = get_global_excludes(lintargs['root'])
         cli.SEARCH_PATHS.append(here)