The ``--always-copy`` option now skips "system" and "development" eggs

since they can't be reliably copied.  Note that this may cause EasyInstall
to choose an older version of a package than what you expected, or it may
cause downloading and installation of a fresh version of what's already
installed.

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4042260

EasyInstall.txt

@@ -589,6 +589,14 @@ Command-Line Options
     from other sys.path directories to the installation directory, unless you
     explicitly gave the distribution's filename on the command line.
 
+    Note that as of 0.6a10, using this option excludes "system" and
+    "development" eggs from consideration because they can't be reliably
+    copied.  This may cause EasyInstall to choose an older version of a package
+    than what you expected, or it may cause downloading and installation of a
+    fresh copy of something that's already installed.  You will see warning
+    messages for any eggs that EasyInstall skips, before it falls back to an
+    older version or attempts to download a fresh copy.
+
 ``--find-links=URL, -f URL`` (Option renamed in 0.4a2)
     Scan the specified "download pages" for direct links to downloadable eggs
     or source distributions.  Any usable packages will be downloaded if they
@@ -982,6 +990,11 @@ Known Issues
    linking to them (e.g. from within their own PyPI page or download links
    page).
 
+ * The ``--always-copy`` option now skips "system" and "development" eggs since
+   they can't be reliably copied.  Note that this may cause EasyInstall to
+   choose an older version of a package than what you expected, or it may cause
+   downloading and installation of a fresh version of what's already installed.
+
 0.6a9
  * Fixed ``.pth`` file processing picking up nested eggs (i.e. ones inside
    "baskets") when they weren't explicitly listed in the ``.pth`` file.

setuptools/command/easy_install.py

@@ -305,27 +305,27 @@ class easy_install(Command):
                     spec = parse_requirement_arg(spec)
 
             self.check_editable(spec)
-            download = self.package_index.fetch(
-                spec, tmpdir, self.upgrade, self.editable
+            dist = self.package_index.fetch_distribution(
+                spec, tmpdir, self.upgrade, self.editable, not self.always_copy
             )
 
-            if download is None:
-                raise DistutilsError(
-                    "Could not find distribution for %r" % spec
-                )
-
-            return self.install_item(spec, download, tmpdir, deps)
+            if dist is None:
+                msg = "Could not find suitable distribution for %r" % spec
+                if self.always_copy:
+                    msg+=" (--always-copy skips system and development eggs)"
+                raise DistutilsError(msg)
+            elif dist.precedence==DEVELOP_DIST:
+                # .egg-info dists don't need installing, just process deps
+                self.process_distribution(spec, dist, deps, "Using")                
+                return dist
+            else:
+                return self.install_item(spec, dist.location, tmpdir, deps)
 
         finally:
             if os.path.exists(tmpdir):
                 rmtree(tmpdir)
 
 
-
-
-
-
-
     def install_item(self, spec, download, tmpdir, deps, install_needed=False):
 
         # Installation is also needed if file in tmpdir or is not an egg

setuptools/package_index.py

@@ -337,12 +337,12 @@ class PackageIndex(Environment):
         automatically created alongside the downloaded file.
 
         If `spec` is a ``Requirement`` object or a string containing a
-        project/version requirement spec, this method is equivalent to
-        the ``fetch()`` method.  If `spec` is a local, existing file or
-        directory name, it is simply returned unchanged.  If `spec` is a URL,
-        it is downloaded to a subpath of `tmpdir`, and the local filename is
-        returned.  Various errors may be raised if a problem occurs during
-        downloading.
+        project/version requirement spec, this method returns the location of
+        a matching distribution (possibly after downloading it to `tmpdir`).
+        If `spec` is a locally existing file or directory name, it is simply
+        returned unchanged.  If `spec` is a URL, it is downloaded to a subpath
+        of `tmpdir`, and the local filename is returned.  Various errors may be
+        raised if a problem occurs during downloading.
         """
         if not isinstance(spec,Requirement):
             scheme = URL_SCHEME(spec)
@@ -364,31 +364,49 @@ class PackageIndex(Environment):
                         "Not a URL, existing file, or requirement spec: %r" %
                         (spec,)
                     )
-        return self.fetch(spec, tmpdir)
+        return getattr(self.fetch_distribution(spec, tmpdir),'location',None)
 
 
-    def fetch(self, requirement, tmpdir, force_scan=False, source=False):
-        """Obtain a file suitable for fulfilling `requirement`
+    def fetch_distribution(self,
+        requirement, tmpdir, force_scan=False, source=False, develop_ok=False
+    ):
+        """Obtain a distribution suitable for fulfilling `requirement`
 
         `requirement` must be a ``pkg_resources.Requirement`` instance.
         If necessary, or if the `force_scan` flag is set, the requirement is
         searched for in the (online) package index as well as the locally
         installed packages.  If a distribution matching `requirement` is found,
-        the return value is the same as if you had called the ``download()``
-        method with the matching distribution's URL.  If no matching
-        distribution is found, returns ``None``.
+        the returned distribution's ``location`` is the value you would have
+        gotten from calling the ``download()`` method with the matching
+        distribution's URL or filename.  If no matching distribution is found,
+        ``None`` is returned.
 
         If the `source` flag is set, only source distributions and source
-        checkout links will be considered.
+        checkout links will be considered.  Unless the `develop_ok` flag is
+        set, development and system eggs (i.e., those using the ``.egg-info``
+        format) will be ignored.
         """
+
         # process a Requirement
         self.info("Searching for %s", requirement)
+        skipped = {}
 
         def find(req):
+            # Find a matching distribution; may be called more than once
+
             for dist in self[req.key]:
+
+                if dist.precedence==DEVELOP_DIST and not develop_ok:
+                    if dist not in skipped:
+                        self.warn("Skipping development or system egg: %s",dist)
+                        skipped[dist] = 1
+                    continue
+
                 if dist in req and (dist.precedence<=SOURCE_DIST or not source):
                     self.info("Best match: %s", dist)
-                    return self.download(dist.location, tmpdir)
+                    return dist.clone(
+                        location=self.download(dist.location, tmpdir)
+                    )
 
         if force_scan:
             self.find_packages(requirement)
@@ -407,6 +425,29 @@ class PackageIndex(Environment):
             )
         return dist
 
+    def fetch(self, requirement, tmpdir, force_scan=False, source=False):
+        """Obtain a file suitable for fulfilling `requirement`
+
+        DEPRECATED; use the ``fetch_distribution()`` method now instead.  For
+        backward compatibility, this routine is identical but returns the
+        ``location`` of the downloaded distribution instead of a distribution
+        object.
+        """
+        dist = self.fetch_dist(requirement,tmpdir,force_scan,source)
+        if dist is not None:
+            return dist.location
+        return None
+
+
+
+
+
+
+
+
+
+
+
 
     def gen_setup(self, filename, fragment, tmpdir):
         match = EGG_FRAGMENT.match(fragment); #import pdb; pdb.set_trace()