Try harder to detect an existing checkout before 'fetch'ing.

fetch.py

 #!/usr/bin/env python
 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Tool to perform checkouts in one easy command line!
 
 Usage:
   fetch <recipe> [--property=value [--property2=value2 ...]]
@@ skipping 45 matching lines @@
   def init(self):
     pass
 
   def sync(self):
     pass
 
   def run(self, cmd, **kwargs):
     print 'Running: %s' % (' '.join(pipes.quote(x) for x in cmd))
     if self.options.dry_run:
       return 0
-    return subprocess.check_call(cmd, **kwargs)
+    return subprocess.check_output(cmd, **kwargs)
 
 
 class GclientCheckout(Checkout):
 
   def run_gclient(self, *cmd, **kwargs):
     if not spawn.find_executable('gclient'):
       cmd_prefix = (sys.executable, os.path.join(SCRIPT_PATH, 'gclient.py'))
     else:
       cmd_prefix = ('gclient',)
     return self.run(cmd_prefix + cmd, **kwargs)
@@ skipping 36 matching lines @@
     for soln in self.spec['solutions']:
       soln_string= '\n'.join('    "%s": %s,' % (key, _format_literal(value))
                              for key, value in soln.iteritems())
       soln_strings.append('  {\n%s\n  },' % soln_string)
     gclient_spec = 'solutions = [\n%s\n]\n' % '\n'.join(soln_strings)
     extra_keys = ['target_os', 'target_os_only']
     gclient_spec += ''.join('%s = %s\n' % (key, _format_literal(self.spec[key]))
                              for key in extra_keys if key in self.spec)
     return gclient_spec
 
   def exists(self):

[agable, 2015/06/10 17:54:28]

Rather than doing this, I would define exists() on the top-level GclientCheckout
and run self.run_gclient('root') to see if it finds a .gclient file. wdyt?

[Michael Moss, 2015/06/10 18:10:47]

Yeah, I wasn't sure how strict we wanted to be, so I was just trying to exclude
"redundant" checkouts, as opposed to "any checkout within any checkout" (though
I don't know why anybody would want to do that). I'm not opposed to the latter
if you think that's better.

[agable, 2015/06/10 18:22:16]

We don't have any GclientSVN-based fetch recipes anymore (and should probably
delete that code because screw svn). So doing it here is probably fine. But the
purist in me really wants to make sure we cover all the cases. And since there's
a base class that understands gclient anyway...

Not necessary. But I think it would be way more elegant and less likely to
surprise someone later down the line.

+    solution_urls = [s.get('url') for s in self.spec.get('solutions', [])]
+    try:
+      current_remote = self.run_git('config', '--get', 'remote.origin.url')
+      if current_remote.strip() in solution_urls:
+        return True
+    except subprocess.CalledProcessError:
+      pass
     return os.path.exists(os.path.join(os.getcwd(), self.root))
 
   def init(self):
     # Configure and do the gclient checkout.
     self.run_gclient('config', '--spec', self._format_spec())
     sync_cmd = ['sync']
     if self.options.nohooks:
       sync_cmd.append('--nohooks')
     if self.options.no_history:
       sync_cmd.append('--no-history')
@@ skipping 174 matching lines @@
       root: The directory into which the repo expects to be checkout out.
   """
   assert 'type' in spec
   checkout_type = spec['type']
   checkout_spec = spec['%s_spec' % checkout_type]
   try:
     checkout = CheckoutFactory(checkout_type, options, checkout_spec, root)
   except KeyError:
     return 1
   if checkout.exists():
-    print 'You appear to already have a checkout. "fetch" is used only'
-    print 'to get new checkouts. Use "gclient sync" to update the checkout.'
+    print 'Your current directory appears to already contain, or be part of, '
+    print 'a checkout. "fetch" is used only to get new checkouts. Use '
+    print '"gclient sync" to update existing checkouts.'
     print
     print 'Fetch also does not yet deal with partial checkouts, so if fetch'
     print 'failed, delete the checkout and start over (crbug.com/230691).'
     return 1
   return checkout.init()
 
 
 def main():
   options, recipe, props = handle_args(sys.argv)
   spec, root = run_recipe_fetch(recipe, props)
   return run(options, spec, root)
 
 
 if __name__ == '__main__':
   try:
     sys.exit(main())
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)