sed: make package discoverable (#25481)

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

@@ -3,6 +3,8 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+import re
+
 from spack import *
 
 
@@ -12,3 +14,12 @@ class Sed(AutotoolsPackage, GNUMirrorPackage):
     gnu_mirror_path = "sed/sed-4.2.2.tar.bz2"
 
     version('4.2.2', sha256='f048d1838da284c8bc9753e4506b85a1e0cc1ea8999d36f6995bcb9460cddbd7')
+
+    executables = ['^sed$']
+
+    @classmethod
+    def determine_version(cls, exe):
+        output = Executable(exe)('--version', output=str, error=str)
+        version_regexp = r'{:s} \(GNU sed\) (\S+)'.format(exe)
+        match = re.search(version_regexp, output)
+        return match.group(1) if match else None