Add completion of locals to spack python (#29702)

lib/spack/spack/cmd/python.py

@@ -118,6 +118,10 @@ def python_interpreter(args):
     else:
         # Provides readline support, allowing user to use arrow keys
         console.push('import readline')
+        # Provide tabcompletion
+        console.push('from rlcompleter import Completer')
+        console.push('readline.set_completer(Completer(locals()).complete)')
+        console.push('readline.parse_and_bind("tab: complete")')
 
         console.interact("Spack version %s\nPython %s, %s %s"
                          % (spack.spack_version, platform.python_version(),