spack.package: re-export PackageBase, register_builder and Builder (#50547)

lib/spack/spack/builder.py

@@ -23,7 +23,7 @@
 _BUILDERS: Dict[int, "Builder"] = {}
 
 
-def builder(build_system_name: str):
+def register_builder(build_system_name: str):
     """Class decorator used to register the default builder
     for a given build-system.
 

lib/spack/spack/package.py

@@ -49,7 +49,7 @@
 from llnl.util.symlink import symlink
 
 from spack.build_environment import MakeExecutable
-from spack.builder import BaseBuilder
+from spack.builder import BaseBuilder, Builder, register_builder
 from spack.config import determine_number_of_jobs
 from spack.deptypes import ALL_TYPES as all_deptypes
 from spack.directives import (
@@ -81,7 +81,13 @@
 )
 from spack.mixins import filter_compiler_wrappers
 from spack.multimethod import default_args, when
-from spack.package_base import build_system_flags, env_flags, inject_flags, on_package_attributes
+from spack.package_base import (
+    PackageBase,
+    build_system_flags,
+    env_flags,
+    inject_flags,
+    on_package_attributes,
+)
 from spack.package_completions import (
     bash_completion_path,
     fish_completion_path,
@@ -216,6 +222,9 @@ class tty:
     "cd",
     "pwd",
     "tty",
+    "Builder",
+    "PackageBase",
+    "register_builder",
 ]
 
 # These are just here for editor support; they may be set when the build env is set up.