Bug 965789 - Check if a clobber is needed before invoking make install-tests, r=gps

python/mozbuild/mozbuild/base.py

@@ -19,6 +19,7 @@ from mach.mixin.process import ProcessExecutionMixin
 from mozfile.mozfile import rmtree
 
 from .backend.configenvironment import ConfigEnvironment
+from .controller.clobber import Clobberer
 from .mozconfig import (
     MozconfigFindException,
     MozconfigLoadException,
@@ -281,6 +282,11 @@ class MozbuildObject(ProcessExecutionMixin):
     def statedir(self):
         return os.path.join(self.topobjdir, '.mozbuild')
 
+    def is_clobber_needed(self):
+        if not os.path.exists(self.topobjdir):
+            return False
+        return Clobberer(self.topsrcdir, self.topobjdir).clobber_needed()
+
     def remove_objdir(self):
         """Remove the entire object directory."""
 

python/mozbuild/mozbuild/controller/building.py

@@ -30,6 +30,26 @@ from ..compilation.warnings import (
     WarningsDatabase,
 )
 
+from textwrap import TextWrapper
+
+INSTALL_TESTS_CLOBBER = ''.join([TextWrapper().fill(line) + '\n' for line in
+'''
+The build system was unable to install tests because the CLOBBER file has \
+been updated. This means if you edited any test files, your changes may not \
+be picked up until a full/clobber build is performed.
+
+The easiest and fastest way to perform a clobber build is to run:
+
+ $ mach clobber
+ $ mach build
+
+If you did not modify any test files, it is safe to ignore this message \
+and proceed with running tests. To do this run:
+
+ $ touch {clobber_file}
+'''.splitlines()])
+
+
 
 BuildOutputResult = namedtuple('BuildOutputResult',
     ('warning', 'state_changed', 'for_display'))
@@ -575,6 +595,11 @@ class BuildDriver(MozbuildObject):
     def install_tests(self, remove=True):
         """Install test files (through manifest)."""
 
+        if self.is_clobber_needed():
+            print(INSTALL_TESTS_CLOBBER.format(
+                  clobber_file=os.path.join(self.topobjdir, 'CLOBBER')))
+            sys.exit(1)
+
         env = {}
         if not remove:
             env[b'NO_REMOVE'] = b'1'