Allow installation directly into environments

bootstrap_dev.py

@@ -7,6 +7,8 @@
 
 from pathlib import Path
 from flit.install import Installer
+from flit.log import enable_colourful_output
 
+enable_colourful_output()
 p = Path('flit.ini')
 Installer(p, symlink=True).install()

flit/__init__.py

@@ -32,6 +32,12 @@ def main(argv=None):
     parser_install.add_argument('--symlink', action='store_true',
         help="Symlink the module/package into site packages instead of copying it"
     )
+    parser_install.add_argument('--user', action='store_true', default=None,
+        help="Do a user-local install (default if site.ENABLE_USER_SITE is True)"
+    )
+    parser_install.add_argument('--env', action='store_false', dest='user',
+        help="Install into sys.prefix (default if site.ENABLE_USER_SITE is False, i.e. in virtualenvs)"
+    )
 
     args = ap.parse_args(argv)
 
@@ -43,7 +49,7 @@ def main(argv=None):
                      verify_metadata=args.verify_metadata).build()
     elif args.subcmd == 'install':
         from .install import Installer
-        Installer(args.ini_file, symlink=args.symlink).install()
+        Installer(args.ini_file, user=args.user, symlink=args.symlink).install()
     else:
         sys.exit('No command specified')
 

flit/install.py

@@ -45,15 +45,27 @@ def get_dirs(user=True):
         'purelib': purelib.format_map(_interpolation_vars),
     }
 
+class RootInstallError(Exception):
+    def __str__(self):
+        return ("Installing packages as root is not recommended. "
+            "To allow this, set FLIT_ROOT_INSTALL=1 and try again.")
+
 class Installer(object):
-    def __init__(self, ini_path, user=True, symlink=False):
+    def __init__(self, ini_path, user=None, symlink=False):
         self.ini_path = ini_path
         self.ini_info = inifile.read_pkg_ini(ini_path)
         self.module = common.Module(self.ini_info['module'],
                                     ini_path.parent)
         self.metadata = common.make_metadata(self.module, self.ini_info)
 
-        self.user = user
+        print(user, site.ENABLE_USER_SITE)
+        if user is None:
+            self.user = site.ENABLE_USER_SITE
+        else:
+            self.user = user
+        if (os.getuid() == 0) and (not os.environ.get('FLIT_ROOT_INSTALL')):
+            raise RootInstallError
+
         self.symlink = symlink
         self.installed_files = []