Overhaul Spack's URL parsing (#2972)

* Remove fake URLs from Spack

* Ignore long lines for URLs that start with ftp:

* Preliminary changes to version regexes

* New redesign of version regexes

* Allow letters in version-only

* Fix detection of versions that end in Final

* Rearrange a few regexes and add examples

* Add tests for common download repositories

* Add test cases for common tarball naming schemes

* Finalize version regexes

* spack url test -> spack url summary

* Clean up comments

* Rearrange suffix checks

* Use query strings for name detection

* Remove no longer necessary url_for_version functions

* Strip off extraneous information after package name

* Add one more test

* Dot in square brackets does not need to be escaped

* Move renaming outside of parse_name_offset

* Fix versions for a couple more packages

* Fix flake8 and doc tests

* Correctly parse Python, Lua, and Bio++ package names

* Use effective URLs for mfem

* Add checksummed version to mitos

* Remove url_for_version from STAR-CCM+ package

* Revert changes to version numbers with underscores and dashes

* Fix name detection for tbb

* Correctly parse Ruby gems

* Reverted mfem back to shortened URLs.

* Updated instructions for better security

* Remove preferred=True from newest version

* Add tests for new `spack url list` flags

* Add tests for strip_name_suffixes

* Add unit tests for version separators

* Fix bugs related to parseable name but in parseable version

* Remove dead code, update docstring

* Ignore 'binary' at end of version string

* Remove platform from version

* Flip libedit version numbers

* Re-support weird NCO alpha/beta versions

* Rebase and remove one new fake URL

* Add / to beginning of regex to avoid picking up similarly named packages

* Ignore weird tar versions

* Fix bug in url parse --spider when no versions found

* Less strict version matching for spack versions

* Don't rename Python packages

* Be a little more selective, version must begin with a digit

* Re-add fake URLs

* Fix up several other packages

* Ignore more file endings

* Add parsing support for Miniconda

* Update tab completion

* XFAILS are now PASSES for 2 web tests

var/spack/repos/builtin/packages/metis/package.py

@@ -37,7 +37,8 @@ class Metis(Package):
        partitioning schemes."""
 
     homepage = "http://glaros.dtc.umn.edu/gkhome/metis/metis/overview"
-    base_url = "http://glaros.dtc.umn.edu/gkhome/fetch/sw/metis"
+    url      = "http://glaros.dtc.umn.edu/gkhome/fetch/sw/metis/metis-5.1.0.tar.gz"
+    list_url = "http://glaros.dtc.umn.edu/gkhome/fetch/sw/metis/OLD"
 
     version('5.1.0', '5465e67079419a69e0116de24fce58fe')
     version('5.0.2', 'acb521a4e8c2e6dd559a7f9abd0468c5')
@@ -55,12 +56,11 @@ class Metis(Package):
     patch('install_gklib_defs_rename.patch', when='@5:')
 
     def url_for_version(self, version):
-        verdir = 'OLD/' if version < Version('4.0.3') else ''
-        return '%s/%smetis-%s.tar.gz' % (Metis.base_url, verdir, version)
-
-    @when('@:4')
-    def patch(self):
-        pass
+        url = "http://glaros.dtc.umn.edu/gkhome/fetch/sw/metis"
+        if version < Version('4.0.3'):
+            url += "/OLD"
+        url += "/metis-{0}.tar.gz".format(version)
+        return url
 
     @when('@5:')
     def patch(self):
@@ -84,7 +84,7 @@ def patch(self):
             filter_file('#define MAX_JBUFS 128', '#define MAX_JBUFS 24',
                         join_path(source_path, 'GKlib', 'error.c'))
 
-    @when('@:4')
+    @when('@:4')  # noqa: F811
     def install(self, spec, prefix):
         # Process library spec and options
         if any('+{0}'.format(v) in spec for v in ['gdb', 'int64', 'real64']):
@@ -175,7 +175,7 @@ def install(self, spec, prefix):
             Executable(test_bin('mesh2dual'))(test_graph('metis.mesh'))
             """
 
-    @when('@5:')
+    @when('@5:')  # noqa: F811
     def install(self, spec, prefix):
         source_directory = self.stage.source_path
         build_directory = join_path(source_directory, 'build')
@@ -187,7 +187,7 @@ def install(self, spec, prefix):
         if '+shared' in spec:
             options.append('-DSHARED:BOOL=ON')
         else:
-            # Remove all RPATH options 
+            # Remove all RPATH options
             # (RPATHxxx options somehow trigger cmake to link dynamically)
             rpath_options = []
             for o in options: