BuildEnvironment: accumulate module changes to poke to all relevant modules (#32340)

Currently, module changes from `setup_dependent_package` are applied only to the module of the package class, but not to any parent classes' modules between the package class module and `spack.package_base`.

In this PR, we create a custom class to accumulate module changes, and apply those changes to each class that requires it. This design allows us to code for a single module, while applying the changes to multiple modules as needed under the hood, without requiring the user to reason about package inheritance.

lib/spack/spack/build_environment.py

@@ -64,6 +64,7 @@
 import spack.subprocess_context
 import spack.user_environment
 import spack.util.path
+import spack.util.pattern
 from spack.error import NoHeadersError, NoLibrariesError
 from spack.installer import InstallError
 from spack.util.cpus import cpus_available
@@ -993,8 +994,24 @@ def add_modifications_for_dep(dep):
             dpkg = dep.package
             if set_package_py_globals:
                 set_module_variables_for_package(dpkg)
+
             # Allow dependencies to modify the module
-            dpkg.setup_dependent_package(spec.package.module, spec)
+            # Get list of modules that may need updating
+            modules = []
+            for cls in inspect.getmro(type(spec.package)):
+                module = cls.module
+                if module == spack.package_base:
+                    break
+                modules.append(module)
+
+            # Execute changes as if on a single module
+            # copy dict to ensure prior changes are available
+            changes = spack.util.pattern.Bunch()
+            dpkg.setup_dependent_package(changes, spec)
+
+            for module in modules:
+                module.__dict__.update(changes.__dict__)
+
             if context == "build":
                 dpkg.setup_dependent_build_environment(env, spec)
             else:

lib/spack/spack/test/build_environment.py

@@ -177,6 +177,14 @@ def _set_wrong_cc(x):
     assert os.environ["ANOTHER_VAR"] == "THIS_IS_SET"
 
 
+def test_setup_dependent_package_inherited_modules(
+    config, working_env, mock_packages, install_mockery, mock_fetch
+):
+    # This will raise on regression
+    s = spack.spec.Spec("cmake-client-inheritor").concretized()
+    s.package.do_install()
+
+
 @pytest.mark.parametrize(
     "initial,modifications,expected",
     [

var/spack/repos/builtin.mock/packages/cmake-client-inheritor/package.py

@@ -0,0 +1,11 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *  # noqa: F401
+from spack.pkg.builtin.mock.cmake_client import CmakeClient
+
+
+class CmakeClientInheritor(CmakeClient):
+    """A dumy package that inherits from one using cmake."""