Don't propagate version-specific URL overrides to newer versions (#8565)

When a user specifies a URL for a specific version of a package, Spack originally
would use that URL for all newer versions of the package. This behavior has
proven to be generally more harmful than useful, so this PR removes the feature
such that a version-specific URL override affects only that version.

lib/spack/spack/package.py

@@ -766,22 +766,6 @@ def version_urls(self):
                 version_urls[v] = args['url']
         return version_urls
 
-    def nearest_url(self, version):
-        """Finds the URL for the next lowest version with a URL.
-           If there is no lower version with a URL, uses the
-           package url property. If that isn't there, uses a
-           *higher* URL, and if that isn't there raises an error.
-        """
-        version_urls = self.version_urls()
-        url = getattr(self.__class__, 'url', None)
-
-        for v in version_urls:
-            if v > version and url:
-                break
-            if version_urls[v]:
-                url = version_urls[v]
-        return url
-
     # TODO: move this out of here and into some URL extrapolation module?
     def url_for_version(self, version):
         """Returns a URL from which the specified version of this package
@@ -804,9 +788,10 @@ def url_for_version(self, version):
         if version in version_urls:
             return version_urls[version]
 
-        # If we have no idea, try to substitute the version.
+        # If we have no idea, substitute the version into the default URL.
+        default_url = getattr(self.__class__, 'url', None)
         return spack.url.substitute_version(
-            self.nearest_url(version), self.url_version(version))
+            default_url, self.url_version(version))
 
     def _make_resource_stage(self, root_stage, fetcher, resource):
         resource_stage_folder = self._resource_stage(resource)

lib/spack/spack/test/packages.py

@@ -165,3 +165,18 @@ def test_import_namespace_container_modules(self):
         import spack.pkg.builtin.mock                   # noqa
         import spack.pkg.builtin.mock as m              # noqa
         from spack.pkg.builtin import mock              # noqa
+
+    @pytest.mark.regression('2737')
+    def test_urls_for_versions(self):
+        # Checks that a version directive without a 'url' argument
+        # specified uses the default url
+        for spec_str in ('url_override@0.9.0', 'url_override@1.0.0'):
+            s = Spec(spec_str).concretized()
+            url = s.package.url_for_version('0.9.0')
+            assert url == 'http://www.anothersite.org/uo-0.9.0.tgz'
+
+            url = s.package.url_for_version('1.0.0')
+            assert url == 'http://www.doesnotexist.org/url_override-1.0.0.tar.gz'
+
+            url = s.package.url_for_version('0.8.1')
+            assert url == 'http://www.doesnotexist.org/url_override-0.8.1.tar.gz'

var/spack/repos/builtin.mock/packages/url_override/package.py

@@ -0,0 +1,34 @@
+##############################################################################
+# Copyright (c) 2013-2018, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/spack/spack
+# Please also see the NOTICE and LICENSE files for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+
+
+class UrlOverride(Package):
+    homepage = 'http://www.doesnotexist.org'
+    url      = 'http://www.doesnotexist.org/url_override-1.0.0.tar.gz'
+
+    version('1.0.0', 'cxyzab')
+    version('0.9.0', 'bcxyza', url='http://www.anothersite.org/uo-0.9.0.tgz')
+    version('0.8.1', 'cxyzab')