# HG changeset patch
# User Chris Manchester <cmanchester@mozilla.com>
# Date 1535134400 0
# Node ID 3b000def0382fee7a4cd9bd7def3a13d8a3cc67b
# Parent  9a9256844c3d545e70ed5e89004a093ace3894d4
Bug 1485174 - Prevent using an objdir to build with tup that was previously used to build with make. r=firefox-build-system-reviewers,froydnj

Differential Revision: https://phabricator.services.mozilla.com/D4154

diff --git a/python/mozbuild/mozbuild/controller/building.py b/python/mozbuild/mozbuild/controller/building.py
--- a/python/mozbuild/mozbuild/controller/building.py
+++ b/python/mozbuild/mozbuild/controller/building.py
@@ -1,16 +1,17 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import absolute_import, unicode_literals
 
 import errno
 import getpass
+import glob
 import io
 import json
 import logging
 import os
 import subprocess
 import sys
 import time
 import which
@@ -1044,16 +1045,26 @@ class BuildDriver(MozbuildObject):
                 if config_rc != 0:
                     return config_rc
 
                 config = self.config_environment
 
             status = None
             active_backend = config.substs.get('BUILD_BACKENDS', [None])[0]
             if active_backend and 'Make' not in active_backend:
+                for backend_file in glob.iglob(mozpath.join(self.topobjdir,
+                                                            'backend.*Backend')):
+                    if 'Make' in backend_file:
+                        self.log(logging.ERROR, 'backend',
+                                 {'objdir': self.topobjdir},
+                                 "The active objdir, {objdir}, was previously "
+                                 "used to build with a Make-based backend. "
+                                 "Change objdirs (by setting MOZ_OBJDIR in "
+                                 "your mozconfig) to continue.\n")
+                        return 1
                 # Record whether a clobber was requested so we can print
                 # a special message later if the build fails.
                 clobber_requested = False
                 # Write out any changes to the current mozconfig in case
                 # they should invalidate configure.
                 self._write_mozconfig_json()
                 # Even if we have a config object, it may be out of date
                 # if something that influences its result has changed.