Bug 1670039 - Always call virtualenv with python -S. r=firefox-build-system-reviewers,perftest-reviewers,mhentges

It disables site modules from the caller python, which are irrelevant
anyways as virtualenv is self-contained.

Differential Revision: https://phabricator.services.mozilla.com/D93064

python/mozbuild/mozbuild/virtualenv.py

@@ -250,7 +250,7 @@ class VirtualenvManager(VirtualenvHelper):
         if os.path.exists(self.virtualenv_root):
             shutil.rmtree(self.virtualenv_root)
 
-        args = [python, self.virtualenv_script_path,
+        args = [python, '-S', self.virtualenv_script_path,
                 # Without this, virtualenv.py may attempt to contact the outside
                 # world and search for or download a newer version of pip,
                 # setuptools, or wheel. This is bad for security, reproducibility,

testing/mozharness/mozharness/base/python.py

@@ -381,6 +381,7 @@ class VirtualenvMixin(object):
 
         virtualenv = [
             sys.executable,
+            '-S',
             venv_py_path,
         ]
         virtualenv_options = c.get('virtualenv_options', [])

testing/raptor/mach_commands.py

@@ -154,7 +154,7 @@ class RaptorRunner(MozbuildObject):
             'base_work_dir': self.mozharness_dir,
             'exes': {
                 'python': self.python,
-                'virtualenv': [self.python, self.virtualenv_script],
+                'virtualenv': [self.python, '-S', self.virtualenv_script],
             },
             'title': socket.gethostname(),
             'default_actions': default_actions,

testing/talos/mach_commands.py

@@ -80,7 +80,7 @@ class TalosRunner(MozbuildObject):
             'base_work_dir': self.mozharness_dir,
             'exes': {
                 'python': self.python_interp,
-                'virtualenv': [self.python_interp, self.virtualenv_script]
+                'virtualenv': [self.python_interp, '-S', self.virtualenv_script]
             },
             'title': socket.gethostname(),
             'default_actions': default_actions,

testing/tps/create_venv.py

@@ -75,7 +75,7 @@ def setup_virtualenv(target, python_bin=None):
             f.extractall(here)
 
         print('Creating new virtual environment')
-        cmd_args = [sys.executable, script_path, target]
+        cmd_args = [sys.executable, '-S', script_path, target]
 
         if python_bin:
             cmd_args.extend(['-p', python_bin])