--- a/contrib/automation/automation.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/automation.py	Sun Oct 06 09:45:02 2019 -0400
@@ -36,8 +36,13 @@
         pip = venv_bin / 'pip'
         python = venv_bin / 'python'
 
-    args = [str(pip), 'install', '-r', str(REQUIREMENTS_TXT),
-            '--disable-pip-version-check']
+    args = [
+        str(pip),
+        'install',
+        '-r',
+        str(REQUIREMENTS_TXT),
+        '--disable-pip-version-check',
+    ]
 
     if not venv_created:
         args.append('-q')
@@ -45,8 +50,7 @@
     subprocess.run(args, check=True)
 
     os.environ['HGAUTOMATION_BOOTSTRAPPED'] = '1'
-    os.environ['PATH'] = '%s%s%s' % (
-        venv_bin, os.pathsep, os.environ['PATH'])
+    os.environ['PATH'] = '%s%s%s' % (venv_bin, os.pathsep, os.environ['PATH'])
 
     subprocess.run([str(python), __file__] + sys.argv[1:], check=True)
 

--- a/contrib/automation/hgautomation/__init__.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/__init__.py	Sun Oct 06 09:45:02 2019 -0400
@@ -10,9 +10,7 @@
 import pathlib
 import secrets
 
-from .aws import (
-    AWSConnection,
-)
+from .aws import AWSConnection
 
 
 class HGAutomation:
@@ -53,7 +51,7 @@
 
         return password
 
-    def aws_connection(self, region: str, ensure_ec2_state: bool=True):
+    def aws_connection(self, region: str, ensure_ec2_state: bool = True):
         """Obtain an AWSConnection instance bound to a specific region."""
 
         return AWSConnection(self, region, ensure_ec2_state=ensure_ec2_state)

--- a/contrib/automation/hgautomation/aws.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/aws.py	Sun Oct 06 09:45:02 2019 -0400
@@ -19,9 +19,7 @@
 import boto3
 import botocore.exceptions
 
-from .linux import (
-    BOOTSTRAP_DEBIAN,
-)
+from .linux import BOOTSTRAP_DEBIAN
 from .ssh import (
     exec_command as ssh_exec_command,
     wait_for_ssh,
@@ -32,10 +30,13 @@
 )
 
 
-SOURCE_ROOT = pathlib.Path(os.path.abspath(__file__)).parent.parent.parent.parent
+SOURCE_ROOT = pathlib.Path(
+    os.path.abspath(__file__)
+).parent.parent.parent.parent
 
-INSTALL_WINDOWS_DEPENDENCIES = (SOURCE_ROOT / 'contrib' /
-                                'install-windows-dependencies.ps1')
+INSTALL_WINDOWS_DEPENDENCIES = (
+    SOURCE_ROOT / 'contrib' / 'install-windows-dependencies.ps1'
+)
 
 
 INSTANCE_TYPES_WITH_STORAGE = {
@@ -107,7 +108,6 @@
                         'Description': 'RDP from entire Internet',
                     },
                 ],
-
             },
             {
                 'FromPort': 5985,
@@ -119,7 +119,7 @@
                         'Description': 'PowerShell Remoting (Windows Remote Management)',
                     },
                 ],
-            }
+            },
         ],
     },
 }
@@ -152,11 +152,7 @@
 
 
 IAM_INSTANCE_PROFILES = {
-    'ephemeral-ec2-1': {
-        'roles': [
-            'ephemeral-ec2-role-1',
-        ],
-    }
+    'ephemeral-ec2-1': {'roles': ['ephemeral-ec2-role-1',],}
 }
 
 
@@ -226,7 +222,7 @@
 class AWSConnection:
     """Manages the state of a connection with AWS."""
 
-    def __init__(self, automation, region: str, ensure_ec2_state: bool=True):
+    def __init__(self, automation, region: str, ensure_ec2_state: bool = True):
         self.automation = automation
         self.local_state_path = automation.state_path
 
@@ -257,10 +253,19 @@
 
     # TODO use rsa package.
     res = subprocess.run(
-        ['openssl', 'pkcs8', '-in', str(p), '-nocrypt', '-topk8',
-         '-outform', 'DER'],
+        [
+            'openssl',
+            'pkcs8',
+            '-in',
+            str(p),
+            '-nocrypt',
+            '-topk8',
+            '-outform',
+            'DER',
+        ],
         capture_output=True,
-        check=True)
+        check=True,
+    )
 
     sha1 = hashlib.sha1(res.stdout).hexdigest()
     return ':'.join(a + b for a, b in zip(sha1[::2], sha1[1::2]))
@@ -271,7 +276,7 @@
 
     for kpi in ec2resource.key_pairs.all():
         if kpi.name.startswith(prefix):
-            remote_existing[kpi.name[len(prefix):]] = kpi.key_fingerprint
+            remote_existing[kpi.name[len(prefix) :]] = kpi.key_fingerprint
 
     # Validate that we have these keys locally.
     key_path = state_path / 'keys'
@@ -297,7 +302,7 @@
         if not f.startswith('keypair-') or not f.endswith('.pub'):
             continue
 
-        name = f[len('keypair-'):-len('.pub')]
+        name = f[len('keypair-') : -len('.pub')]
 
         pub_full = key_path / f
         priv_full = key_path / ('keypair-%s' % name)
@@ -306,8 +311,9 @@
             data = fh.read()
 
         if not data.startswith('ssh-rsa '):
-            print('unexpected format for key pair file: %s; removing' %
-                  pub_full)
+            print(
+                'unexpected format for key pair file: %s; removing' % pub_full
+            )
             pub_full.unlink()
             priv_full.unlink()
             continue
@@ -327,8 +333,10 @@
             del local_existing[name]
 
         elif remote_existing[name] != local_existing[name]:
-            print('key fingerprint mismatch for %s; '
-                  'removing from local and remote' % name)
+            print(
+                'key fingerprint mismatch for %s; '
+                'removing from local and remote' % name
+            )
             remove_local(name)
             remove_remote('%s%s' % (prefix, name))
             del local_existing[name]
@@ -356,15 +364,18 @@
             subprocess.run(
                 ['ssh-keygen', '-y', '-f', str(priv_full)],
                 stdout=fh,
-                check=True)
+                check=True,
+            )
 
         pub_full.chmod(0o0600)
 
 
 def delete_instance_profile(profile):
     for role in profile.roles:
-        print('removing role %s from instance profile %s' % (role.name,
-                                                             profile.name))
+        print(
+            'removing role %s from instance profile %s'
+            % (role.name, profile.name)
+        )
         profile.remove_role(RoleName=role.name)
 
     print('deleting instance profile %s' % profile.name)
@@ -378,7 +389,7 @@
 
     for profile in iamresource.instance_profiles.all():
         if profile.name.startswith(prefix):
-            remote_profiles[profile.name[len(prefix):]] = profile
+            remote_profiles[profile.name[len(prefix) :]] = profile
 
     for name in sorted(set(remote_profiles) - set(IAM_INSTANCE_PROFILES)):
         delete_instance_profile(remote_profiles[name])
@@ -388,7 +399,7 @@
 
     for role in iamresource.roles.all():
         if role.name.startswith(prefix):
-            remote_roles[role.name[len(prefix):]] = role
+            remote_roles[role.name[len(prefix) :]] = role
 
     for name in sorted(set(remote_roles) - set(IAM_ROLES)):
         role = remote_roles[name]
@@ -404,7 +415,8 @@
         print('creating IAM instance profile %s' % actual)
 
         profile = iamresource.create_instance_profile(
-            InstanceProfileName=actual)
+            InstanceProfileName=actual
+        )
         remote_profiles[name] = profile
 
         waiter = iamclient.get_waiter('instance_profile_exists')
@@ -453,23 +465,12 @@
 
     images = ec2resource.images.filter(
         Filters=[
-            {
-                'Name': 'owner-id',
-                'Values': [owner_id],
-            },
-            {
-                'Name': 'state',
-                'Values': ['available'],
-            },
-            {
-                'Name': 'image-type',
-                'Values': ['machine'],
-            },
-            {
-                'Name': 'name',
-                'Values': [name],
-            },
-        ])
+            {'Name': 'owner-id', 'Values': [owner_id],},
+            {'Name': 'state', 'Values': ['available'],},
+            {'Name': 'image-type', 'Values': ['machine'],},
+            {'Name': 'name', 'Values': [name],},
+        ]
+    )
 
     for image in images:
         return image
@@ -487,7 +488,7 @@
 
     for group in ec2resource.security_groups.all():
         if group.group_name.startswith(prefix):
-            existing[group.group_name[len(prefix):]] = group
+            existing[group.group_name[len(prefix) :]] = group
 
     purge = set(existing) - set(SECURITY_GROUPS)
 
@@ -507,13 +508,10 @@
         print('adding security group %s' % actual)
 
         group_res = ec2resource.create_security_group(
-            Description=group['description'],
-            GroupName=actual,
+            Description=group['description'], GroupName=actual,
         )
 
-        group_res.authorize_ingress(
-            IpPermissions=group['ingress'],
-        )
+        group_res.authorize_ingress(IpPermissions=group['ingress'],)
 
         security_groups[name] = group_res
 
@@ -577,8 +575,10 @@
                 instance.reload()
                 continue
 
-            print('public IP address for %s: %s' % (
-                instance.id, instance.public_ip_address))
+            print(
+                'public IP address for %s: %s'
+                % (instance.id, instance.public_ip_address)
+            )
             break
 
 
@@ -603,10 +603,7 @@
     while True:
         res = ssmclient.describe_instance_information(
             Filters=[
-                {
-                    'Key': 'InstanceIds',
-                    'Values': [i.id for i in instances],
-                },
+                {'Key': 'InstanceIds', 'Values': [i.id for i in instances],},
             ],
         )
 
@@ -628,9 +625,7 @@
         InstanceIds=[i.id for i in instances],
         DocumentName=document_name,
         Parameters=parameters,
-        CloudWatchOutputConfig={
-            'CloudWatchOutputEnabled': True,
-        },
+        CloudWatchOutputConfig={'CloudWatchOutputEnabled': True,},
     )
 
     command_id = res['Command']['CommandId']
@@ -639,8 +634,7 @@
         while True:
             try:
                 res = ssmclient.get_command_invocation(
-                    CommandId=command_id,
-                    InstanceId=instance.id,
+                    CommandId=command_id, InstanceId=instance.id,
                 )
             except botocore.exceptions.ClientError as e:
                 if e.response['Error']['Code'] == 'InvocationDoesNotExist':
@@ -655,8 +649,9 @@
             elif res['Status'] in ('Pending', 'InProgress', 'Delayed'):
                 time.sleep(2)
             else:
-                raise Exception('command failed on %s: %s' % (
-                    instance.id, res['Status']))
+                raise Exception(
+                    'command failed on %s: %s' % (instance.id, res['Status'])
+                )
 
 
 @contextlib.contextmanager
@@ -711,10 +706,12 @@
     config['IamInstanceProfile'] = {
         'Name': 'hg-ephemeral-ec2-1',
     }
-    config.setdefault('TagSpecifications', []).append({
-        'ResourceType': 'instance',
-        'Tags': [{'Key': 'Name', 'Value': 'hg-temp-windows'}],
-    })
+    config.setdefault('TagSpecifications', []).append(
+        {
+            'ResourceType': 'instance',
+            'Tags': [{'Key': 'Name', 'Value': 'hg-temp-windows'}],
+        }
+    )
     config['UserData'] = WINDOWS_USER_DATA % password
 
     with temporary_ec2_instances(c.ec2resource, config) as instances:
@@ -723,7 +720,9 @@
         print('waiting for Windows Remote Management service...')
 
         for instance in instances:
-            client = wait_for_winrm(instance.public_ip_address, 'Administrator', password)
+            client = wait_for_winrm(
+                instance.public_ip_address, 'Administrator', password
+            )
             print('established WinRM connection to %s' % instance.id)
             instance.winrm_client = client
 
@@ -748,14 +747,17 @@
     # Store a reference to a good image so it can be returned one the
     # image state is reconciled.
     images = ec2resource.images.filter(
-        Filters=[{'Name': 'name', 'Values': [name]}])
+        Filters=[{'Name': 'name', 'Values': [name]}]
+    )
 
     existing_image = None
 
     for image in images:
         if image.tags is None:
-            print('image %s for %s lacks required tags; removing' % (
-                image.id, image.name))
+            print(
+                'image %s for %s lacks required tags; removing'
+                % (image.id, image.name)
+            )
             remove_ami(ec2resource, image)
         else:
             tags = {t['Key']: t['Value'] for t in image.tags}
@@ -763,15 +765,18 @@
             if tags.get('HGIMAGEFINGERPRINT') == fingerprint:
                 existing_image = image
             else:
-                print('image %s for %s has wrong fingerprint; removing' % (
-                      image.id, image.name))
+                print(
+                    'image %s for %s has wrong fingerprint; removing'
+                    % (image.id, image.name)
+                )
                 remove_ami(ec2resource, image)
 
     return existing_image
 
 
-def create_ami_from_instance(ec2client, instance, name, description,
-                             fingerprint):
+def create_ami_from_instance(
+    ec2client, instance, name, description, fingerprint
+):
     """Create an AMI from a running instance.
 
     Returns the ``ec2resource.Image`` representing the created AMI.
@@ -779,29 +784,19 @@
     instance.stop()
 
     ec2client.get_waiter('instance_stopped').wait(
-        InstanceIds=[instance.id],
-        WaiterConfig={
-            'Delay': 5,
-        })
+        InstanceIds=[instance.id], WaiterConfig={'Delay': 5,}
+    )
     print('%s is stopped' % instance.id)
 
-    image = instance.create_image(
-        Name=name,
-        Description=description,
-    )
+    image = instance.create_image(Name=name, Description=description,)
 
-    image.create_tags(Tags=[
-        {
-            'Key': 'HGIMAGEFINGERPRINT',
-            'Value': fingerprint,
-        },
-    ])
+    image.create_tags(
+        Tags=[{'Key': 'HGIMAGEFINGERPRINT', 'Value': fingerprint,},]
+    )
 
     print('waiting for image %s' % image.id)
 
-    ec2client.get_waiter('image_available').wait(
-        ImageIds=[image.id],
-    )
+    ec2client.get_waiter('image_available').wait(ImageIds=[image.id],)
 
     print('image %s available as %s' % (image.id, image.name))
 
@@ -827,9 +822,7 @@
         ssh_username = 'admin'
     elif distro == 'debian10':
         image = find_image(
-            ec2resource,
-            DEBIAN_ACCOUNT_ID_2,
-            'debian-10-amd64-20190909-10',
+            ec2resource, DEBIAN_ACCOUNT_ID_2, 'debian-10-amd64-20190909-10',
         )
         ssh_username = 'admin'
     elif distro == 'ubuntu18.04':
@@ -871,10 +864,12 @@
         'SecurityGroupIds': [c.security_groups['linux-dev-1'].id],
     }
 
-    requirements2_path = (pathlib.Path(__file__).parent.parent /
-                          'linux-requirements-py2.txt')
-    requirements3_path = (pathlib.Path(__file__).parent.parent /
-                          'linux-requirements-py3.txt')
+    requirements2_path = (
+        pathlib.Path(__file__).parent.parent / 'linux-requirements-py2.txt'
+    )
+    requirements3_path = (
+        pathlib.Path(__file__).parent.parent / 'linux-requirements-py3.txt'
+    )
     with requirements2_path.open('r', encoding='utf-8') as fh:
         requirements2 = fh.read()
     with requirements3_path.open('r', encoding='utf-8') as fh:
@@ -882,12 +877,14 @@
 
     # Compute a deterministic fingerprint to determine whether image needs to
     # be regenerated.
-    fingerprint = resolve_fingerprint({
-        'instance_config': config,
-        'bootstrap_script': BOOTSTRAP_DEBIAN,
-        'requirements_py2': requirements2,
-        'requirements_py3': requirements3,
-    })
+    fingerprint = resolve_fingerprint(
+        {
+            'instance_config': config,
+            'bootstrap_script': BOOTSTRAP_DEBIAN,
+            'requirements_py2': requirements2,
+            'requirements_py3': requirements3,
+        }
+    )
 
     existing_image = find_and_reconcile_image(ec2resource, name, fingerprint)
 
@@ -902,9 +899,11 @@
         instance = instances[0]
 
         client = wait_for_ssh(
-            instance.public_ip_address, 22,
+            instance.public_ip_address,
+            22,
             username=ssh_username,
-            key_filename=str(c.key_pair_path_private('automation')))
+            key_filename=str(c.key_pair_path_private('automation')),
+        )
 
         home = '/home/%s' % ssh_username
 
@@ -926,8 +925,9 @@
                 fh.chmod(0o0700)
 
             print('executing bootstrap')
-            chan, stdin, stdout = ssh_exec_command(client,
-                                                   '%s/bootstrap' % home)
+            chan, stdin, stdout = ssh_exec_command(
+                client, '%s/bootstrap' % home
+            )
             stdin.close()
 
             for line in stdout:
@@ -937,17 +937,28 @@
             if res:
                 raise Exception('non-0 exit from bootstrap: %d' % res)
 
-            print('bootstrap completed; stopping %s to create %s' % (
-                  instance.id, name))
+            print(
+                'bootstrap completed; stopping %s to create %s'
+                % (instance.id, name)
+            )
 
-        return create_ami_from_instance(ec2client, instance, name,
-                                        'Mercurial Linux development environment',
-                                        fingerprint)
+        return create_ami_from_instance(
+            ec2client,
+            instance,
+            name,
+            'Mercurial Linux development environment',
+            fingerprint,
+        )
 
 
 @contextlib.contextmanager
-def temporary_linux_dev_instances(c: AWSConnection, image, instance_type,
-                                  prefix='hg-', ensure_extra_volume=False):
+def temporary_linux_dev_instances(
+    c: AWSConnection,
+    image,
+    instance_type,
+    prefix='hg-',
+    ensure_extra_volume=False,
+):
     """Create temporary Linux development EC2 instances.
 
     Context manager resolves to a list of ``ec2.Instance`` that were created
@@ -979,8 +990,9 @@
 
     # This is not an exhaustive list of instance types having instance storage.
     # But
-    if (ensure_extra_volume
-        and not instance_type.startswith(tuple(INSTANCE_TYPES_WITH_STORAGE))):
+    if ensure_extra_volume and not instance_type.startswith(
+        tuple(INSTANCE_TYPES_WITH_STORAGE)
+    ):
         main_device = block_device_mappings[0]['DeviceName']
 
         if main_device == 'xvda':
@@ -988,17 +1000,20 @@
         elif main_device == '/dev/sda1':
             second_device = '/dev/sdb'
         else:
-            raise ValueError('unhandled primary EBS device name: %s' %
-                             main_device)
+            raise ValueError(
+                'unhandled primary EBS device name: %s' % main_device
+            )
 
-        block_device_mappings.append({
-            'DeviceName': second_device,
-            'Ebs': {
-                'DeleteOnTermination': True,
-                'VolumeSize': 8,
-                'VolumeType': 'gp2',
+        block_device_mappings.append(
+            {
+                'DeviceName': second_device,
+                'Ebs': {
+                    'DeleteOnTermination': True,
+                    'VolumeSize': 8,
+                    'VolumeType': 'gp2',
+                },
             }
-        })
+        )
 
     config = {
         'BlockDeviceMappings': block_device_mappings,
@@ -1019,9 +1034,11 @@
 
         for instance in instances:
             client = wait_for_ssh(
-                instance.public_ip_address, 22,
+                instance.public_ip_address,
+                22,
                 username='hg',
-                key_filename=ssh_private_key_path)
+                key_filename=ssh_private_key_path,
+            )
 
             instance.ssh_client = client
             instance.ssh_private_key_path = ssh_private_key_path
@@ -1033,8 +1050,9 @@
                 instance.ssh_client.close()
 
 
-def ensure_windows_dev_ami(c: AWSConnection, prefix='hg-',
-                           base_image_name=WINDOWS_BASE_IMAGE_NAME):
+def ensure_windows_dev_ami(
+    c: AWSConnection, prefix='hg-', base_image_name=WINDOWS_BASE_IMAGE_NAME
+):
     """Ensure Windows Development AMI is available and up-to-date.
 
     If necessary, a modern AMI will be built by starting a temporary EC2
@@ -1100,13 +1118,15 @@
 
     # Compute a deterministic fingerprint to determine whether image needs
     # to be regenerated.
-    fingerprint = resolve_fingerprint({
-        'instance_config': config,
-        'user_data': WINDOWS_USER_DATA,
-        'initial_bootstrap': WINDOWS_BOOTSTRAP_POWERSHELL,
-        'bootstrap_commands': commands,
-        'base_image_name': base_image_name,
-    })
+    fingerprint = resolve_fingerprint(
+        {
+            'instance_config': config,
+            'user_data': WINDOWS_USER_DATA,
+            'initial_bootstrap': WINDOWS_BOOTSTRAP_POWERSHELL,
+            'bootstrap_commands': commands,
+            'base_image_name': base_image_name,
+        }
+    )
 
     existing_image = find_and_reconcile_image(ec2resource, name, fingerprint)
 
@@ -1131,9 +1151,7 @@
             ssmclient,
             [instance],
             'AWS-RunPowerShellScript',
-            {
-                'commands': WINDOWS_BOOTSTRAP_POWERSHELL.split('\n'),
-            },
+            {'commands': WINDOWS_BOOTSTRAP_POWERSHELL.split('\n'),},
         )
 
         # Reboot so all updates are fully applied.
@@ -1145,10 +1163,8 @@
         print('rebooting instance %s' % instance.id)
         instance.stop()
         ec2client.get_waiter('instance_stopped').wait(
-            InstanceIds=[instance.id],
-            WaiterConfig={
-                'Delay': 5,
-            })
+            InstanceIds=[instance.id], WaiterConfig={'Delay': 5,}
+        )
 
         instance.start()
         wait_for_ip_addresses([instance])
@@ -1159,8 +1175,11 @@
         # TODO figure out a workaround.
 
         print('waiting for Windows Remote Management to come back...')
-        client = wait_for_winrm(instance.public_ip_address, 'Administrator',
-                                c.automation.default_password())
+        client = wait_for_winrm(
+            instance.public_ip_address,
+            'Administrator',
+            c.automation.default_password(),
+        )
         print('established WinRM connection to %s' % instance.id)
         instance.winrm_client = client
 
@@ -1168,14 +1187,23 @@
         run_powershell(instance.winrm_client, '\n'.join(commands))
 
         print('bootstrap completed; stopping %s to create image' % instance.id)
-        return create_ami_from_instance(ec2client, instance, name,
-                                        'Mercurial Windows development environment',
-                                        fingerprint)
+        return create_ami_from_instance(
+            ec2client,
+            instance,
+            name,
+            'Mercurial Windows development environment',
+            fingerprint,
+        )
 
 
 @contextlib.contextmanager
-def temporary_windows_dev_instances(c: AWSConnection, image, instance_type,
-                                    prefix='hg-', disable_antivirus=False):
+def temporary_windows_dev_instances(
+    c: AWSConnection,
+    image,
+    instance_type,
+    prefix='hg-',
+    disable_antivirus=False,
+):
     """Create a temporary Windows development EC2 instance.
 
     Context manager resolves to the list of ``EC2.Instance`` that were created.
@@ -1205,6 +1233,7 @@
             for instance in instances:
                 run_powershell(
                     instance.winrm_client,
-                    'Set-MpPreference -DisableRealtimeMonitoring $true')
+                    'Set-MpPreference -DisableRealtimeMonitoring $true',
+                )
 
         yield instances

--- a/contrib/automation/hgautomation/cli.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/cli.py	Sun Oct 06 09:45:02 2019 -0400
@@ -22,12 +22,15 @@
 )
 
 
-SOURCE_ROOT = pathlib.Path(os.path.abspath(__file__)).parent.parent.parent.parent
+SOURCE_ROOT = pathlib.Path(
+    os.path.abspath(__file__)
+).parent.parent.parent.parent
 DIST_PATH = SOURCE_ROOT / 'dist'
 
 
-def bootstrap_linux_dev(hga: HGAutomation, aws_region, distros=None,
-                        parallel=False):
+def bootstrap_linux_dev(
+    hga: HGAutomation, aws_region, distros=None, parallel=False
+):
     c = hga.aws_connection(aws_region)
 
     if distros:
@@ -59,8 +62,9 @@
     print('Windows development AMI available as %s' % image.id)
 
 
-def build_inno(hga: HGAutomation, aws_region, arch, revision, version,
-               base_image_name):
+def build_inno(
+    hga: HGAutomation, aws_region, arch, revision, version, base_image_name
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_windows_dev_ami(c, base_image_name=base_image_name)
     DIST_PATH.mkdir(exist_ok=True)
@@ -71,13 +75,14 @@
         windows.synchronize_hg(SOURCE_ROOT, revision, instance)
 
         for a in arch:
-            windows.build_inno_installer(instance.winrm_client, a,
-                                         DIST_PATH,
-                                         version=version)
+            windows.build_inno_installer(
+                instance.winrm_client, a, DIST_PATH, version=version
+            )
 
 
-def build_wix(hga: HGAutomation, aws_region, arch, revision, version,
-              base_image_name):
+def build_wix(
+    hga: HGAutomation, aws_region, arch, revision, version, base_image_name
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_windows_dev_ami(c, base_image_name=base_image_name)
     DIST_PATH.mkdir(exist_ok=True)
@@ -88,12 +93,14 @@
         windows.synchronize_hg(SOURCE_ROOT, revision, instance)
 
         for a in arch:
-            windows.build_wix_installer(instance.winrm_client, a,
-                                        DIST_PATH, version=version)
+            windows.build_wix_installer(
+                instance.winrm_client, a, DIST_PATH, version=version
+            )
 
 
-def build_windows_wheel(hga: HGAutomation, aws_region, arch, revision,
-                        base_image_name):
+def build_windows_wheel(
+    hga: HGAutomation, aws_region, arch, revision, base_image_name
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_windows_dev_ami(c, base_image_name=base_image_name)
     DIST_PATH.mkdir(exist_ok=True)
@@ -107,8 +114,9 @@
             windows.build_wheel(instance.winrm_client, a, DIST_PATH)
 
 
-def build_all_windows_packages(hga: HGAutomation, aws_region, revision,
-                               version, base_image_name):
+def build_all_windows_packages(
+    hga: HGAutomation, aws_region, revision, version, base_image_name
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_windows_dev_ami(c, base_image_name=base_image_name)
     DIST_PATH.mkdir(exist_ok=True)
@@ -124,11 +132,13 @@
             windows.purge_hg(winrm_client)
             windows.build_wheel(winrm_client, arch, DIST_PATH)
             windows.purge_hg(winrm_client)
-            windows.build_inno_installer(winrm_client, arch, DIST_PATH,
-                                         version=version)
+            windows.build_inno_installer(
+                winrm_client, arch, DIST_PATH, version=version
+            )
             windows.purge_hg(winrm_client)
-            windows.build_wix_installer(winrm_client, arch, DIST_PATH,
-                                        version=version)
+            windows.build_wix_installer(
+                winrm_client, arch, DIST_PATH, version=version
+            )
 
 
 def terminate_ec2_instances(hga: HGAutomation, aws_region):
@@ -141,8 +151,15 @@
     aws.remove_resources(c)
 
 
-def run_tests_linux(hga: HGAutomation, aws_region, instance_type,
-                    python_version, test_flags, distro, filesystem):
+def run_tests_linux(
+    hga: HGAutomation,
+    aws_region,
+    instance_type,
+    python_version,
+    test_flags,
+    distro,
+    filesystem,
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_linux_dev_ami(c, distro=distro)
 
@@ -151,17 +168,17 @@
     ensure_extra_volume = filesystem not in ('default', 'tmpfs')
 
     with aws.temporary_linux_dev_instances(
-        c, image, instance_type,
-        ensure_extra_volume=ensure_extra_volume) as insts:
+        c, image, instance_type, ensure_extra_volume=ensure_extra_volume
+    ) as insts:
 
         instance = insts[0]
 
-        linux.prepare_exec_environment(instance.ssh_client,
-                                       filesystem=filesystem)
+        linux.prepare_exec_environment(
+            instance.ssh_client, filesystem=filesystem
+        )
         linux.synchronize_hg(SOURCE_ROOT, instance, '.')
         t_prepared = time.time()
-        linux.run_tests(instance.ssh_client, python_version,
-                        test_flags)
+        linux.run_tests(instance.ssh_client, python_version, test_flags)
         t_done = time.time()
 
     t_setup = t_prepared - t_start
@@ -169,29 +186,48 @@
 
     print(
         'total time: %.1fs; setup: %.1fs; tests: %.1fs; setup overhead: %.1f%%'
-        % (t_all, t_setup, t_done - t_prepared, t_setup / t_all * 100.0))
+        % (t_all, t_setup, t_done - t_prepared, t_setup / t_all * 100.0)
+    )
 
 
-def run_tests_windows(hga: HGAutomation, aws_region, instance_type,
-                      python_version, arch, test_flags, base_image_name):
+def run_tests_windows(
+    hga: HGAutomation,
+    aws_region,
+    instance_type,
+    python_version,
+    arch,
+    test_flags,
+    base_image_name,
+):
     c = hga.aws_connection(aws_region)
     image = aws.ensure_windows_dev_ami(c, base_image_name=base_image_name)
 
-    with aws.temporary_windows_dev_instances(c, image, instance_type,
-                                             disable_antivirus=True) as insts:
+    with aws.temporary_windows_dev_instances(
+        c, image, instance_type, disable_antivirus=True
+    ) as insts:
         instance = insts[0]
 
         windows.synchronize_hg(SOURCE_ROOT, '.', instance)
-        windows.run_tests(instance.winrm_client, python_version, arch,
-                          test_flags)
+        windows.run_tests(
+            instance.winrm_client, python_version, arch, test_flags
+        )
 
 
-def publish_windows_artifacts(hg: HGAutomation, aws_region, version: str,
-                              pypi: bool, mercurial_scm_org: bool,
-                              ssh_username: str):
-    windows.publish_artifacts(DIST_PATH, version,
-                              pypi=pypi, mercurial_scm_org=mercurial_scm_org,
-                              ssh_username=ssh_username)
+def publish_windows_artifacts(
+    hg: HGAutomation,
+    aws_region,
+    version: str,
+    pypi: bool,
+    mercurial_scm_org: bool,
+    ssh_username: str,
+):
+    windows.publish_artifacts(
+        DIST_PATH,
+        version,
+        pypi=pypi,
+        mercurial_scm_org=mercurial_scm_org,
+        ssh_username=ssh_username,
+    )
 
 
 def run_try(hga: HGAutomation, aws_region: str, rev: str):
@@ -208,25 +244,21 @@
         help='Path for local state files',
     )
     parser.add_argument(
-        '--aws-region',
-        help='AWS region to use',
-        default='us-west-2',
+        '--aws-region', help='AWS region to use', default='us-west-2',
     )
 
     subparsers = parser.add_subparsers()
 
     sp = subparsers.add_parser(
-        'bootstrap-linux-dev',
-        help='Bootstrap Linux development environments',
+        'bootstrap-linux-dev', help='Bootstrap Linux development environments',
     )
     sp.add_argument(
-        '--distros',
-        help='Comma delimited list of distros to bootstrap',
+        '--distros', help='Comma delimited list of distros to bootstrap',
     )
     sp.add_argument(
         '--parallel',
         action='store_true',
-        help='Generate AMIs in parallel (not CTRL-c safe)'
+        help='Generate AMIs in parallel (not CTRL-c safe)',
     )
     sp.set_defaults(func=bootstrap_linux_dev)
 
@@ -242,17 +274,13 @@
     sp.set_defaults(func=bootstrap_windows_dev)
 
     sp = subparsers.add_parser(
-        'build-all-windows-packages',
-        help='Build all Windows packages',
+        'build-all-windows-packages', help='Build all Windows packages',
     )
     sp.add_argument(
-        '--revision',
-        help='Mercurial revision to build',
-        default='.',
+        '--revision', help='Mercurial revision to build', default='.',
     )
     sp.add_argument(
-        '--version',
-        help='Mercurial version string to use',
+        '--version', help='Mercurial version string to use',
     )
     sp.add_argument(
         '--base-image-name',
@@ -262,8 +290,7 @@
     sp.set_defaults(func=build_all_windows_packages)
 
     sp = subparsers.add_parser(
-        'build-inno',
-        help='Build Inno Setup installer(s)',
+        'build-inno', help='Build Inno Setup installer(s)',
     )
     sp.add_argument(
         '--arch',
@@ -273,13 +300,10 @@
         default=['x64'],
     )
     sp.add_argument(
-        '--revision',
-        help='Mercurial revision to build',
-        default='.',
+        '--revision', help='Mercurial revision to build', default='.',
     )
     sp.add_argument(
-        '--version',
-        help='Mercurial version string to use in installer',
+        '--version', help='Mercurial version string to use in installer',
     )
     sp.add_argument(
         '--base-image-name',
@@ -289,8 +313,7 @@
     sp.set_defaults(func=build_inno)
 
     sp = subparsers.add_parser(
-        'build-windows-wheel',
-        help='Build Windows wheel(s)',
+        'build-windows-wheel', help='Build Windows wheel(s)',
     )
     sp.add_argument(
         '--arch',
@@ -300,9 +323,7 @@
         default=['x64'],
     )
     sp.add_argument(
-        '--revision',
-        help='Mercurial revision to build',
-        default='.',
+        '--revision', help='Mercurial revision to build', default='.',
     )
     sp.add_argument(
         '--base-image-name',
@@ -311,10 +332,7 @@
     )
     sp.set_defaults(func=build_windows_wheel)
 
-    sp = subparsers.add_parser(
-        'build-wix',
-        help='Build WiX installer(s)'
-    )
+    sp = subparsers.add_parser('build-wix', help='Build WiX installer(s)')
     sp.add_argument(
         '--arch',
         help='Architecture to build for',
@@ -323,13 +341,10 @@
         default=['x64'],
     )
     sp.add_argument(
-        '--revision',
-        help='Mercurial revision to build',
-        default='.',
+        '--revision', help='Mercurial revision to build', default='.',
     )
     sp.add_argument(
-        '--version',
-        help='Mercurial version string to use in installer',
+        '--version', help='Mercurial version string to use in installer',
     )
     sp.add_argument(
         '--base-image-name',
@@ -345,15 +360,11 @@
     sp.set_defaults(func=terminate_ec2_instances)
 
     sp = subparsers.add_parser(
-        'purge-ec2-resources',
-        help='Purge all EC2 resources managed by us',
+        'purge-ec2-resources', help='Purge all EC2 resources managed by us',
     )
     sp.set_defaults(func=purge_ec2_resources)
 
-    sp = subparsers.add_parser(
-        'run-tests-linux',
-        help='Run tests on Linux',
-    )
+    sp = subparsers.add_parser('run-tests-linux', help='Run tests on Linux',)
     sp.add_argument(
         '--distro',
         help='Linux distribution to run tests on',
@@ -374,8 +385,18 @@
     sp.add_argument(
         '--python-version',
         help='Python version to use',
-        choices={'system2', 'system3', '2.7', '3.5', '3.6', '3.7', '3.8',
-                 'pypy', 'pypy3.5', 'pypy3.6'},
+        choices={
+            'system2',
+            'system3',
+            '2.7',
+            '3.5',
+            '3.6',
+            '3.7',
+            '3.8',
+            'pypy',
+            'pypy3.5',
+            'pypy3.6',
+        },
         default='system2',
     )
     sp.add_argument(
@@ -386,13 +407,10 @@
     sp.set_defaults(func=run_tests_linux)
 
     sp = subparsers.add_parser(
-        'run-tests-windows',
-        help='Run tests on Windows',
+        'run-tests-windows', help='Run tests on Windows',
     )
     sp.add_argument(
-        '--instance-type',
-        help='EC2 instance type to use',
-        default='t3.medium',
+        '--instance-type', help='EC2 instance type to use', default='t3.medium',
     )
     sp.add_argument(
         '--python-version',
@@ -407,8 +425,7 @@
         default='x64',
     )
     sp.add_argument(
-        '--test-flags',
-        help='Extra command line flags to pass to run-tests.py',
+        '--test-flags', help='Extra command line flags to pass to run-tests.py',
     )
     sp.add_argument(
         '--base-image-name',
@@ -419,7 +436,7 @@
 
     sp = subparsers.add_parser(
         'publish-windows-artifacts',
-        help='Publish built Windows artifacts (wheels, installers, etc)'
+        help='Publish built Windows artifacts (wheels, installers, etc)',
     )
     sp.add_argument(
         '--no-pypi',
@@ -436,22 +453,17 @@
         help='Skip uploading to www.mercurial-scm.org',
     )
     sp.add_argument(
-        '--ssh-username',
-        help='SSH username for mercurial-scm.org',
+        '--ssh-username', help='SSH username for mercurial-scm.org',
     )
     sp.add_argument(
-        'version',
-        help='Mercurial version string to locate local packages',
+        'version', help='Mercurial version string to locate local packages',
     )
     sp.set_defaults(func=publish_windows_artifacts)
 
     sp = subparsers.add_parser(
-        'try',
-        help='Run CI automation against a custom changeset'
+        'try', help='Run CI automation against a custom changeset'
     )
-    sp.add_argument('-r', '--rev',
-                    default='.',
-                    help='Revision to run CI on')
+    sp.add_argument('-r', '--rev', default='.', help='Revision to run CI on')
     sp.set_defaults(func=run_try)
 
     return parser

--- a/contrib/automation/hgautomation/linux.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/linux.py	Sun Oct 06 09:45:02 2019 -0400
@@ -13,9 +13,7 @@
 import subprocess
 import tempfile
 
-from .ssh import (
-    exec_command,
-)
+from .ssh import exec_command
 
 
 # Linux distributions that are supported.
@@ -62,7 +60,9 @@
 done
 
 pyenv global ${PYENV2_VERSIONS} ${PYENV3_VERSIONS} system
-'''.lstrip().replace('\r\n', '\n')
+'''.lstrip().replace(
+    '\r\n', '\n'
+)
 
 
 INSTALL_RUST = r'''
@@ -87,10 +87,13 @@
 echo "${HG_SHA256} ${HG_TARBALL}" | sha256sum --check -
 
 /hgdev/venv-bootstrap/bin/pip install ${HG_TARBALL}
-'''.lstrip().replace('\r\n', '\n')
+'''.lstrip().replace(
+    '\r\n', '\n'
+)
 
 
-BOOTSTRAP_DEBIAN = r'''
+BOOTSTRAP_DEBIAN = (
+    r'''
 #!/bin/bash
 
 set -ex
@@ -323,11 +326,14 @@
 EOF
 
 sudo chown -R hg:hg /hgdev
-'''.lstrip().format(
-    install_rust=INSTALL_RUST,
-    install_pythons=INSTALL_PYTHONS,
-    bootstrap_virtualenv=BOOTSTRAP_VIRTUALENV
-).replace('\r\n', '\n')
+'''.lstrip()
+    .format(
+        install_rust=INSTALL_RUST,
+        install_pythons=INSTALL_PYTHONS,
+        bootstrap_virtualenv=BOOTSTRAP_VIRTUALENV,
+    )
+    .replace('\r\n', '\n')
+)
 
 
 # Prepares /hgdev for operations.
@@ -409,7 +415,9 @@
 chown hg:hg /hgwork/tmp
 
 rsync -a /hgdev/src /hgwork/
-'''.lstrip().replace('\r\n', '\n')
+'''.lstrip().replace(
+    '\r\n', '\n'
+)
 
 
 HG_UPDATE_CLEAN = '''
@@ -421,7 +429,9 @@
 ${HG} --config extensions.purge= purge --all
 ${HG} update -C $1
 ${HG} log -r .
-'''.lstrip().replace('\r\n', '\n')
+'''.lstrip().replace(
+    '\r\n', '\n'
+)
 
 
 def prepare_exec_environment(ssh_client, filesystem='default'):
@@ -456,11 +466,12 @@
     res = chan.recv_exit_status()
 
     if res:
-        raise Exception('non-0 exit code updating working directory; %d'
-                        % res)
+        raise Exception('non-0 exit code updating working directory; %d' % res)
 
 
-def synchronize_hg(source_path: pathlib.Path, ec2_instance, revision: str=None):
+def synchronize_hg(
+    source_path: pathlib.Path, ec2_instance, revision: str = None
+):
     """Synchronize a local Mercurial source path to remote EC2 instance."""
 
     with tempfile.TemporaryDirectory() as temp_dir:
@@ -482,8 +493,10 @@
             fh.write('  IdentityFile %s\n' % ec2_instance.ssh_private_key_path)
 
         if not (source_path / '.hg').is_dir():
-            raise Exception('%s is not a Mercurial repository; synchronization '
-                            'not yet supported' % source_path)
+            raise Exception(
+                '%s is not a Mercurial repository; synchronization '
+                'not yet supported' % source_path
+            )
 
         env = dict(os.environ)
         env['HGPLAIN'] = '1'
@@ -493,17 +506,29 @@
 
         res = subprocess.run(
             ['python2.7', str(hg_bin), 'log', '-r', revision, '-T', '{node}'],
-            cwd=str(source_path), env=env, check=True, capture_output=True)
+            cwd=str(source_path),
+            env=env,
+            check=True,
+            capture_output=True,
+        )
 
         full_revision = res.stdout.decode('ascii')
 
         args = [
-            'python2.7', str(hg_bin),
-            '--config', 'ui.ssh=ssh -F %s' % ssh_config,
-            '--config', 'ui.remotecmd=/hgdev/venv-bootstrap/bin/hg',
+            'python2.7',
+            str(hg_bin),
+            '--config',
+            'ui.ssh=ssh -F %s' % ssh_config,
+            '--config',
+            'ui.remotecmd=/hgdev/venv-bootstrap/bin/hg',
             # Also ensure .hgtags changes are present so auto version
             # calculation works.
-            'push', '-f', '-r', full_revision, '-r', 'file(.hgtags)',
+            'push',
+            '-f',
+            '-r',
+            full_revision,
+            '-r',
+            'file(.hgtags)',
             'ssh://%s//hgwork/src' % public_ip,
         ]
 
@@ -522,7 +547,8 @@
             fh.chmod(0o0700)
 
         chan, stdin, stdout = exec_command(
-            ec2_instance.ssh_client, '/hgdev/hgup %s' % full_revision)
+            ec2_instance.ssh_client, '/hgdev/hgup %s' % full_revision
+        )
         stdin.close()
 
         for line in stdout:
@@ -531,8 +557,9 @@
         res = chan.recv_exit_status()
 
         if res:
-            raise Exception('non-0 exit code updating working directory; %d'
-                            % res)
+            raise Exception(
+                'non-0 exit code updating working directory; %d' % res
+            )
 
 
 def run_tests(ssh_client, python_version, test_flags=None):
@@ -554,8 +581,8 @@
 
     command = (
         '/bin/sh -c "export TMPDIR=/hgwork/tmp; '
-        'cd /hgwork/src/tests && %s run-tests.py %s"' % (
-            python, test_flags))
+        'cd /hgwork/src/tests && %s run-tests.py %s"' % (python, test_flags)
+    )
 
     chan, stdin, stdout = exec_command(ssh_client, command)
 

--- a/contrib/automation/hgautomation/pypi.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/pypi.py	Sun Oct 06 09:45:02 2019 -0400
@@ -7,12 +7,8 @@
 
 # no-check-code because Python 3 native.
 
-from twine.commands.upload import (
-    upload as twine_upload,
-)
-from twine.settings import (
-    Settings,
-)
+from twine.commands.upload import upload as twine_upload
+from twine.settings import Settings
 
 
 def upload(paths):

--- a/contrib/automation/hgautomation/ssh.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/ssh.py	Sun Oct 06 09:45:02 2019 -0400
@@ -11,14 +11,13 @@
 import time
 import warnings
 
-from cryptography.utils import (
-    CryptographyDeprecationWarning,
-)
+from cryptography.utils import CryptographyDeprecationWarning
 import paramiko
 
 
 def wait_for_ssh(hostname, port, timeout=60, username=None, key_filename=None):
     """Wait for an SSH server to start on the specified host and port."""
+
     class IgnoreHostKeyPolicy(paramiko.MissingHostKeyPolicy):
         def missing_host_key(self, client, hostname, key):
             return
@@ -28,17 +27,23 @@
     # paramiko triggers a CryptographyDeprecationWarning in the cryptography
     # package. Let's suppress
     with warnings.catch_warnings():
-        warnings.filterwarnings('ignore',
-                                category=CryptographyDeprecationWarning)
+        warnings.filterwarnings(
+            'ignore', category=CryptographyDeprecationWarning
+        )
 
         while True:
             client = paramiko.SSHClient()
             client.set_missing_host_key_policy(IgnoreHostKeyPolicy())
             try:
-                client.connect(hostname, port=port, username=username,
-                               key_filename=key_filename,
-                               timeout=5.0, allow_agent=False,
-                               look_for_keys=False)
+                client.connect(
+                    hostname,
+                    port=port,
+                    username=username,
+                    key_filename=key_filename,
+                    timeout=5.0,
+                    allow_agent=False,
+                    look_for_keys=False,
+                )
 
                 return client
             except socket.error:

--- a/contrib/automation/hgautomation/windows.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/contrib/automation/hgautomation/windows.py	Sun Oct 06 09:45:02 2019 -0400
@@ -15,12 +15,8 @@
 import subprocess
 import tempfile
 
-from .pypi import (
-    upload as pypi_upload,
-)
-from .winrm import (
-    run_powershell,
-)
+from .pypi import upload as pypi_upload
+from .winrm import run_powershell
 
 
 # PowerShell commands to activate a Visual Studio 2008 environment.
@@ -117,14 +113,21 @@
 X86_USER_AGENT_PATTERN = '.*Windows.*'
 X64_USER_AGENT_PATTERN = '.*Windows.*(WOW|x)64.*'
 
-X86_EXE_DESCRIPTION = ('Mercurial {version} Inno Setup installer - x86 Windows '
-                       '- does not require admin rights')
-X64_EXE_DESCRIPTION = ('Mercurial {version} Inno Setup installer - x64 Windows '
-                       '- does not require admin rights')
-X86_MSI_DESCRIPTION = ('Mercurial {version} MSI installer - x86 Windows '
-                       '- requires admin rights')
-X64_MSI_DESCRIPTION = ('Mercurial {version} MSI installer - x64 Windows '
-                       '- requires admin rights')
+X86_EXE_DESCRIPTION = (
+    'Mercurial {version} Inno Setup installer - x86 Windows '
+    '- does not require admin rights'
+)
+X64_EXE_DESCRIPTION = (
+    'Mercurial {version} Inno Setup installer - x64 Windows '
+    '- does not require admin rights'
+)
+X86_MSI_DESCRIPTION = (
+    'Mercurial {version} MSI installer - x86 Windows ' '- requires admin rights'
+)
+X64_MSI_DESCRIPTION = (
+    'Mercurial {version} MSI installer - x64 Windows ' '- requires admin rights'
+)
+
 
 def get_vc_prefix(arch):
     if arch == 'x86':
@@ -158,10 +161,21 @@
         ssh_dir.chmod(0o0700)
 
         # Generate SSH key to use for communication.
-        subprocess.run([
-            'ssh-keygen', '-t', 'rsa', '-b', '4096', '-N', '',
-            '-f', str(ssh_dir / 'id_rsa')],
-            check=True, capture_output=True)
+        subprocess.run(
+            [
+                'ssh-keygen',
+                '-t',
+                'rsa',
+                '-b',
+                '4096',
+                '-N',
+                '',
+                '-f',
+                str(ssh_dir / 'id_rsa'),
+            ],
+            check=True,
+            capture_output=True,
+        )
 
         # Add it to ~/.ssh/authorized_keys on remote.
         # This assumes the file doesn't already exist.
@@ -182,8 +196,10 @@
             fh.write('  IdentityFile %s\n' % (ssh_dir / 'id_rsa'))
 
         if not (hg_repo / '.hg').is_dir():
-            raise Exception('%s is not a Mercurial repository; '
-                            'synchronization not yet supported' % hg_repo)
+            raise Exception(
+                '%s is not a Mercurial repository; '
+                'synchronization not yet supported' % hg_repo
+            )
 
         env = dict(os.environ)
         env['HGPLAIN'] = '1'
@@ -193,17 +209,29 @@
 
         res = subprocess.run(
             ['python2.7', str(hg_bin), 'log', '-r', revision, '-T', '{node}'],
-            cwd=str(hg_repo), env=env, check=True, capture_output=True)
+            cwd=str(hg_repo),
+            env=env,
+            check=True,
+            capture_output=True,
+        )
 
         full_revision = res.stdout.decode('ascii')
 
         args = [
-            'python2.7', hg_bin,
-            '--config', 'ui.ssh=ssh -F %s' % ssh_config,
-            '--config', 'ui.remotecmd=c:/hgdev/venv-bootstrap/Scripts/hg.exe',
+            'python2.7',
+            hg_bin,
+            '--config',
+            'ui.ssh=ssh -F %s' % ssh_config,
+            '--config',
+            'ui.remotecmd=c:/hgdev/venv-bootstrap/Scripts/hg.exe',
             # Also ensure .hgtags changes are present so auto version
             # calculation works.
-            'push', '-f', '-r', full_revision, '-r', 'file(.hgtags)',
+            'push',
+            '-f',
+            '-r',
+            full_revision,
+            '-r',
+            'file(.hgtags)',
             'ssh://%s/c:/hgdev/src' % public_ip,
         ]
 
@@ -213,8 +241,9 @@
         if res.returncode not in (0, 1):
             res.check_returncode()
 
-        run_powershell(winrm_client,
-                       HG_UPDATE_CLEAN.format(revision=full_revision))
+        run_powershell(
+            winrm_client, HG_UPDATE_CLEAN.format(revision=full_revision)
+        )
 
         # TODO detect dirty local working directory and synchronize accordingly.
 
@@ -250,8 +279,9 @@
     winrm_client.fetch(source, str(dest))
 
 
-def build_inno_installer(winrm_client, arch: str, dest_path: pathlib.Path,
-                         version=None):
+def build_inno_installer(
+    winrm_client, arch: str, dest_path: pathlib.Path, version=None
+):
     """Build the Inno Setup installer on a remote machine.
 
     Using a WinRM client, remote commands are executed to build
@@ -263,8 +293,9 @@
     if version:
         extra_args.extend(['--version', version])
 
-    ps = get_vc_prefix(arch) + BUILD_INNO.format(arch=arch,
-                                                 extra_args=' '.join(extra_args))
+    ps = get_vc_prefix(arch) + BUILD_INNO.format(
+        arch=arch, extra_args=' '.join(extra_args)
+    )
     run_powershell(winrm_client, ps)
     copy_latest_dist(winrm_client, '*.exe', dest_path)
 
@@ -281,8 +312,9 @@
     copy_latest_dist(winrm_client, '*.whl', dest_path)
 
 
-def build_wix_installer(winrm_client, arch: str, dest_path: pathlib.Path,
-                        version=None):
+def build_wix_installer(
+    winrm_client, arch: str, dest_path: pathlib.Path, version=None
+):
     """Build the WiX installer on a remote machine.
 
     Using a WinRM client, remote commands are executed to build a WiX installer.
@@ -292,8 +324,9 @@
     if version:
         extra_args.extend(['--version', version])
 
-    ps = get_vc_prefix(arch) + BUILD_WIX.format(arch=arch,
-                                                extra_args=' '.join(extra_args))
+    ps = get_vc_prefix(arch) + BUILD_WIX.format(
+        arch=arch, extra_args=' '.join(extra_args)
+    )
     run_powershell(winrm_client, ps)
     copy_latest_dist(winrm_client, '*.msi', dest_path)
 
@@ -307,18 +340,16 @@
     ``run-tests.py``.
     """
     if not re.match(r'\d\.\d', python_version):
-        raise ValueError(r'python_version must be \d.\d; got %s' %
-                         python_version)
+        raise ValueError(
+            r'python_version must be \d.\d; got %s' % python_version
+        )
 
     if arch not in ('x86', 'x64'):
         raise ValueError('arch must be x86 or x64; got %s' % arch)
 
     python_path = 'python%s-%s' % (python_version.replace('.', ''), arch)
 
-    ps = RUN_TESTS.format(
-        python_path=python_path,
-        test_flags=test_flags or '',
-    )
+    ps = RUN_TESTS.format(python_path=python_path, test_flags=test_flags or '',)
 
     run_powershell(winrm_client, ps)
 
@@ -374,8 +405,8 @@
             version,
             X64_USER_AGENT_PATTERN,
             '%s/%s' % (MERCURIAL_SCM_BASE_URL, x64_msi_filename),
-            X64_MSI_DESCRIPTION.format(version=version)
-        )
+            X64_MSI_DESCRIPTION.format(version=version),
+        ),
     )
 
     lines = ['\t'.join(e) for e in entries]
@@ -396,8 +427,9 @@
     pypi_upload(wheel_paths)
 
 
-def publish_artifacts_mercurial_scm_org(dist_path: pathlib.Path, version: str,
-                                        ssh_username=None):
+def publish_artifacts_mercurial_scm_org(
+    dist_path: pathlib.Path, version: str, ssh_username=None
+):
     """Publish Windows release artifacts to mercurial-scm.org."""
     all_paths = resolve_all_artifacts(dist_path, version)
 
@@ -436,7 +468,8 @@
 
     now = datetime.datetime.utcnow()
     backup_path = dist_path / (
-        'latest-windows-%s.dat' % now.strftime('%Y%m%dT%H%M%S'))
+        'latest-windows-%s.dat' % now.strftime('%Y%m%dT%H%M%S')
+    )
     print('backing up %s to %s' % (latest_dat_path, backup_path))
 
     with sftp.open(latest_dat_path, 'rb') as fh:
@@ -453,9 +486,13 @@
         fh.write(latest_dat_content.encode('ascii'))
 
 
-def publish_artifacts(dist_path: pathlib.Path, version: str,
-                      pypi=True, mercurial_scm_org=True,
-                      ssh_username=None):
+def publish_artifacts(
+    dist_path: pathlib.Path,
+    version: str,
+    pypi=True,
+    mercurial_scm_org=True,
+    ssh_username=None,
+):
     """Publish Windows release artifacts.
 
     Files are found in `dist_path`. We will look for files with version string
@@ -468,5 +505,6 @@
         publish_artifacts_pypi(dist_path, version)
 
     if mercurial_scm_org:
-        publish_artifacts_mercurial_scm_org(dist_path, version,
-                                            ssh_username=ssh_username)
+        publish_artifacts_mercurial_scm_org(
+            dist_path, version, ssh_username=ssh_username
+        )