Fix --upgrade to leave already up-to-date packages alone. Add --force…

…-reinstall to force reinstallation even of up-to-date packages, as was the prior behavior.

pip/commands/install.py

@@ -106,6 +106,12 @@ def __init__(self):
             dest='upgrade',
             action='store_true',
             help='Upgrade all packages to the newest available version')
+        self.parser.add_option(
+            '--force-reinstall',
+            dest='force_reinstall',
+            action='store_true',
+            help='When upgrading, reinstall all packages even if they are '
+                 'already up-to-date.')
         self.parser.add_option(
             '-I', '--ignore-installed',
             dest='ignore_installed',
@@ -190,7 +196,8 @@ def run(self, options, args):
             download_cache=options.download_cache,
             upgrade=options.upgrade,
             ignore_installed=options.ignore_installed,
-            ignore_dependencies=options.ignore_dependencies)
+            ignore_dependencies=options.ignore_dependencies,
+            force_reinstall=options.force_reinstall)
         for name in args:
             requirement_set.add_requirement(
                 InstallRequirement.from_line(name, None))

pip/exceptions.py

@@ -13,6 +13,11 @@ class DistributionNotFound(InstallationError):
     """Raised when a distribution cannot be found to satisfy a requirement"""
 
 
+class BestVersionAlreadyInstalled(Exception):
+    """Raised when the most up-to-date version of a package is already
+    installed.
+    """
+
 class BadCommand(Exception):
     """Raised when virtualenv or a command is not found"""
 

pip/index.py

@@ -15,7 +15,7 @@
 from pip.log import logger
 from pip.util import Inf
 from pip.util import normalize_name, splitext
-from pip.exceptions import DistributionNotFound
+from pip.exceptions import DistributionNotFound, BestVersionAlreadyInstalled
 from pip.backwardcompat import (WindowsError, BytesIO,
                                 Queue, httplib, urlparse,
                                 URLError, HTTPError, u,
@@ -172,6 +172,7 @@ def mkurl_pypi_url(url):
             if applicable_versions[0][1] is Inf:
                 logger.info('Existing installed version (%s) is most up-to-date and satisfies requirement'
                             % req.satisfied_by.version)
+                raise BestVersionAlreadyInstalled
             else:
                 logger.info('Existing installed version (%s) satisfies requirement (most up-to-date version is %s)'
                             % (req.satisfied_by.version, applicable_versions[0][1]))
@@ -184,7 +185,7 @@ def mkurl_pypi_url(url):
             # We have an existing version, and its the best version
             logger.info('Installed version (%s) is most up-to-date (past versions: %s)'
                         % (req.satisfied_by.version, ', '.join([version for link, version in applicable_versions[1:]]) or 'none'))
-            return None
+            raise BestVersionAlreadyInstalled
         if len(applicable_versions) > 1:
             logger.info('Using version %s (newest of versions: %s)' %
                         (applicable_versions[0][1], ', '.join([version for link, version in applicable_versions])))

pip/req.py

@@ -6,7 +6,8 @@
 import pkg_resources
 import tempfile
 from pip.locations import bin_py, running_under_virtualenv
-from pip.exceptions import InstallationError, UninstallationError
+from pip.exceptions import (InstallationError, UninstallationError,
+                            BestVersionAlreadyInstalled)
 from pip.vcs import vcs
 from pip.log import logger
 from pip.util import display_path, rmtree
@@ -776,13 +777,14 @@ class RequirementSet(object):
 
     def __init__(self, build_dir, src_dir, download_dir, download_cache=None,
                  upgrade=False, ignore_installed=False,
-                 ignore_dependencies=False):
+                 ignore_dependencies=False, force_reinstall=False):
         self.build_dir = build_dir
         self.src_dir = src_dir
         self.download_dir = download_dir
         self.download_cache = download_cache
         self.upgrade = upgrade
         self.ignore_installed = ignore_installed
+        self.force_reinstall = force_reinstall
         self.requirements = Requirements()
         # Mapping of alias: real_name
         self.requirement_aliases = {}
@@ -903,18 +905,35 @@ def prepare_files(self, finder, force_root_egg_info=False, bundle=False):
             else:
                 req_to_install = reqs.pop(0)
             install = True
+            best_installed = False
             if not self.ignore_installed and not req_to_install.editable:
                 req_to_install.check_if_exists()
                 if req_to_install.satisfied_by:
                     if self.upgrade:
-                        req_to_install.conflicts_with = req_to_install.satisfied_by
-                        req_to_install.satisfied_by = None
+                        if not self.force_reinstall:
+                            try:
+                                finder.find_requirement(req_to_install,
+                                                        self.uninstall)
+                            except BestVersionAlreadyInstalled:
+                                best_installed = True
+                                install = False
+                            except:
+                                # Ignore DistributionNotFound for now
+                                pass
+
+                        if self.force_reinstall or not best_installed:
+                            req_to_install.conflicts_with = req_to_install.satisfied_by
+                            req_to_install.satisfied_by = None
                     else:
                         install = False
                 if req_to_install.satisfied_by:
-                    logger.notify('Requirement already satisfied '
-                                  '(use --upgrade to upgrade): %s'
-                                  % req_to_install)
+                    if best_installed:
+                        logger.notify('Requirement already up-to-date: %s'
+                                      % req_to_install)
+                    else:
+                        logger.notify('Requirement already satisfied '
+                                      '(use --upgrade to upgrade): %s'
+                                      % req_to_install)
             if req_to_install.editable:
                 logger.notify('Obtaining %s' % req_to_install)
             elif install:
@@ -1081,7 +1100,7 @@ def unpack_url(self, link, location, only_download=False):
     def install(self, install_options, global_options=()):
         """Install everything in this set (after having downloaded and unpacked the packages)"""
         to_install = [r for r in self.requirements.values()
-                      if self.upgrade or not r.satisfied_by]
+                      if (self.upgrade and not r.satisfied_by) or not r.satisfied_by]
 
         if to_install:
             logger.notify('Installing collected packages: %s' % ', '.join([req.name for req in to_install]))