Add recursive and quiet flags to mb lookup.

Change-Id: Ica0e38196c37e00e2503b8674323b64ce6490554
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1576022
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Auto-Submit: Garrett Beaty <gbeaty@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652900}

tools/mb/mb.py

@@ -173,6 +173,12 @@ class MetaBuildWrapper(object):
                             help='look up the command for a given config or '
                                  'builder')
     AddCommonOptions(subp)
+    subp.add_argument('--quiet', default=False, action='store_true',
+                      help='Print out just the arguments, '
+                           'do not emulate the output of the gen subcommand.')
+    subp.add_argument('--recursive', default=False, action='store_true',
+                      help='Lookup arguments from imported files, '
+                           'implies --quiet')
     subp.set_defaults(func=self.CmdLookup)
 
     subp = subps.add_parser(
@@ -330,12 +336,15 @@ class MetaBuildWrapper(object):
 
   def CmdLookup(self):
     vals = self.Lookup()
-    cmd = self.GNCmd('gen', '_path_')
-    gn_args = self.GNArgs(vals)
-    self.Print('\nWriting """\\\n%s""" to _path_/args.gn.\n' % gn_args)
-    env = None
+    gn_args = self.GNArgs(vals, expand_imports=self.args.recursive)
+    if self.args.quiet or self.args.recursive:
+      self.Print(gn_args, end='')
+    else:
+      cmd = self.GNCmd('gen', '_path_')
+      self.Print('\nWriting """\\\n%s""" to _path_/args.gn.\n' % gn_args)
+      env = None
 
-    self.PrintCmd(cmd, env)
+      self.PrintCmd(cmd, env)
     return 0
 
   def CmdRun(self):
@@ -1087,7 +1096,7 @@ class MetaBuildWrapper(object):
     return [gn_path, subcommand, path] + list(args)
 
 
-  def GNArgs(self, vals):
+  def GNArgs(self, vals, expand_imports=False):
     if vals['cros_passthrough']:
       if not 'GN_ARGS' in os.environ:
         raise MBErr('MB is expecting GN_ARGS to be in the environment')
@@ -1111,26 +1120,34 @@ class MetaBuildWrapper(object):
     if android_version_name:
       gn_args += ' android_default_version_name="%s"' % android_version_name
 
-    # Canonicalize the arg string into a sorted, newline-separated list
-    # of key-value pairs, and de-dup the keys if need be so that only
-    # the last instance of each arg is listed.
-    gn_args = gn_helpers.ToGNString(gn_helpers.FromGNArgs(gn_args))
+    args_gn_lines = []
+    parsed_gn_args = {}
 
     # If we're using the Simple Chrome SDK, add a comment at the top that
     # points to the doc. This must happen after the gn_helpers.ToGNString()
     # call above since gn_helpers strips comments.
     if vals['cros_passthrough']:
-      simplechrome_comment = [
+      args_gn_lines.extend([
           '# These args are generated via the Simple Chrome SDK. See the link',
           '# below for more details:',
           '# https://chromium.googlesource.com/chromiumos/docs/+/master/simple_chrome_workflow.md',  # pylint: disable=line-too-long
-      ]
-      gn_args = '%s\n%s' % ('\n'.join(simplechrome_comment), gn_args)
+      ])
 
     args_file = vals.get('args_file', None)
     if args_file:
-      gn_args = ('import("%s")\n' % vals['args_file']) + gn_args
-    return gn_args
+      if expand_imports:
+        content = self.ReadFile(self.ToAbsPath(args_file))
+        parsed_gn_args = gn_helpers.FromGNArgs(content)
+      else:
+        args_gn_lines.append('import("%s")' % args_file)
+
+    # Canonicalize the arg string into a sorted, newline-separated list
+    # of key-value pairs, and de-dup the keys if need be so that only
+    # the last instance of each arg is listed.
+    parsed_gn_args.update(gn_helpers.FromGNArgs(gn_args))
+    args_gn_lines.append(gn_helpers.ToGNString(parsed_gn_args))
+
+    return '\n'.join(args_gn_lines)
 
   def GetIsolateCommand(self, target, vals):
     isolate_map = self.ReadIsolateMap()

tools/mb/mb_unittest.py

@@ -657,7 +657,18 @@ class UnitTest(unittest.TestCase):
                 '//out/Default', 'base_unittests'], mbw=mbw, ret=0)
 
   def test_lookup(self):
-    self.check(['lookup', '-c', 'debug_goma'], ret=0)
+    self.check(['lookup', '-c', 'debug_goma'], ret=0,
+               out=('\n'
+                    'Writing """\\\n'
+                    'is_debug = true\n'
+                    'use_goma = true\n'
+                    '""" to _path_/args.gn.\n\n'
+                    '/fake_src/buildtools/linux64/gn gen _path_\n'))
+
+  def test_quiet_lookup(self):
+    self.check(['lookup', '-c', 'debug_goma', '--quiet'], ret=0,
+               out=('is_debug = true\n'
+                    'use_goma = true\n'))
 
   def test_lookup_goma_dir_expansion(self):
     self.check(['lookup', '-c', 'rel_bot', '-g', '/foo'], ret=0,
@@ -711,6 +722,19 @@ class UnitTest(unittest.TestCase):
                       '--phase', 'phase_2'], ret=0)
     self.assertIn('phase = 2', mbw.out)
 
+  def test_recursive_lookup(self):
+    files = {
+        '/fake_src/build/args/fake.gn': (
+          'enable_doom_melon = true\n'
+          'enable_antidoom_banana = true\n'
+        )
+    }
+    self.check(['lookup', '-m', 'fake_master', '-b', 'fake_args_file',
+                '--recursive'], files=files, ret=0,
+               out=('enable_antidoom_banana = true\n'
+                    'enable_doom_melon = true\n'
+                    'use_goma = true\n'))
+
   def test_validate(self):
     mbw = self.fake_mbw()
     self.check(['validate'], mbw=mbw, ret=0)