path exists action

pip/basecommand.py

@@ -75,6 +75,9 @@ class Command(object):
         
         if options.no_input:
             os.environ['PIP_NO_INPUT'] = '1'
+            
+        if options.exists_action:
+            os.environ['PIP_EXISTS_ACTION'] = ''.join(options.exists_action)
 
         if options.require_venv:
             # If a venv is required check if it can really be found

pip/baseparser.py

@@ -200,4 +200,20 @@ parser.add_option(
     default='',
     help=optparse.SUPPRESS_HELP)
 
+parser.add_option(
+    # Option when path already exist
+    '--exists-action',
+    dest='exists_action',
+    type='choice',
+    choices=('s', 'i', 'w', 'b'),
+    default=[],
+    action='append',
+    help="Default action when a path already exists."
+    "Use this option more then one time to specify another action when a certain option is not available, choices: "
+    "(s)witch,"
+    "(i)gnore,"
+    "(w)ipe,"
+    "(b)ackup"
+)
+
 parser.disable_interspersed_args()

pip/download.py

@@ -10,7 +10,7 @@ from pip.backwardcompat import (md5, copytree, xmlrpclib, urllib, urllib2,
                                 urlparse, string_types, HTTPError)
 from pip.exceptions import InstallationError
 from pip.util import (splitext, rmtree,
-                      format_size, display_path, backup_dir, ask,
+                      format_size, display_path, backup_dir, ask, path_exists,
                       unpack_file, create_download_cache_folder, cache_download)
 from pip.vcs import vcs
 from pip.log import logger
@@ -388,7 +388,7 @@ def _copy_file(filename, location, content_type, link):
     copy = True
     download_location = os.path.join(location, link.filename)
     if os.path.exists(download_location):
-        response = ask('The file %s exists. (i)gnore, (w)ipe, (b)ackup '
+        response = path_exists('The file %s exists. (i)gnore, (w)ipe, (b)ackup '
                        % display_path(download_location), ('i', 'w', 'b'))
         if response == 'i':
             copy = False

pip/req.py

@@ -10,7 +10,7 @@ from pip.exceptions import InstallationError, UninstallationError
 from pip.vcs import vcs
 from pip.log import logger
 from pip.util import display_path, rmtree
-from pip.util import ask, backup_dir
+from pip.util import ask, path_exists, backup_dir
 from pip.util import is_installable_dir, is_local, dist_is_local
 from pip.util import renames, normalize_path, egg_link_path
 from pip.util import make_path_relative
@@ -502,7 +502,7 @@ exec(compile(open(__file__).read().replace('\\r\\n', '\\n'), __file__, 'exec'))
         archive_name = '%s-%s.zip' % (self.name, self.installed_version)
         archive_path = os.path.join(build_dir, archive_name)
         if os.path.exists(archive_path):
-            response = ask('The file %s exists. (i)gnore, (w)ipe, (b)ackup '
+            response = path_exists('The file %s exists. (i)gnore, (w)ipe, (b)ackup '
                            % display_path(archive_path), ('i', 'w', 'b'))
             if response == 'i':
                 create_archive = False

pip/util.py

@@ -102,6 +102,11 @@ def get_pathext(default_pathext=None):
     pathext = os.environ.get('PATHEXT', default_pathext)
     return pathext
 
+def path_exists(message, options):
+    for action in os.environ.get('PIP_EXISTS_ACTION', ''):
+        if action in options:
+            return action
+    return ask(message, options)
 
 def ask(message, options):
     """Ask the message interactively, with the given possible responses"""

pip/vcs/__init__.py

@@ -5,7 +5,7 @@ import shutil
 
 from pip.backwardcompat import urlparse, urllib
 from pip.log import logger
-from pip.util import display_path, backup_dir, find_command, ask, rmtree
+from pip.util import display_path, backup_dir, find_command, ask, rmtree, path_exists
 
 
 __all__ = ['vcs', 'get_src_requirement']
@@ -198,7 +198,7 @@ class VersionControl(object):
         if prompt:
             logger.warn('The plan is to install the %s repository %s'
                         % (self.name, url))
-            response = ask('What to do?  %s' % prompt[0], prompt[1])
+            response = path_exists('What to do?  %s' % prompt[0], prompt[1])
 
             if response == 's':
                 logger.notify('Switching %s %s to %s%s'