Test historical build fingerprints with their pinned renderer

tests/validation/taylor_green/test_projected_pairs.py

@@ -249,35 +249,41 @@ class ProjectedPairsTests(unittest.TestCase):
         self.assertFalse(assess(incomplete)["comparisons"][3]["passed"])
 
     def test_pinned_build_sources_match_host_generated_inputs(self):
-        """The pinned fingerprints are what today's compiler generates from the qualified
+        """Check the pinned fingerprints using NUMERICAL_REVISION's renderer and kernels.
-        NUMERICAL_REVISION kernels; the current kernels may legitimately differ."""
+        The imported LBMConfig is unchanged from that revision; this is a host
+        build-input check, not a reconstruction of the historical CUDA toolchain."""
+        import importlib.util
         import tarfile
-        from CelerisLab.cuda import compiler_v2
 
         kernels = "src/CelerisLab/lbm/kernels"
+        renderer = "src/CelerisLab/cuda/compiler_v2.py"
         if subprocess.run(["git", "-C", str(REPO), "cat-file", "-e",
                            f"{NUMERICAL_REVISION}^{{commit}}"], capture_output=True).returncode:
             self.fail(f"{NUMERICAL_REVISION} is not in this clone; the pinned build "
                       "sources cannot be checked")
         archive = subprocess.run(["git", "-C", str(REPO), "archive", "--format=tar",
-                                  NUMERICAL_REVISION, kernels],
+                                  NUMERICAL_REVISION, kernels, renderer],
                                  capture_output=True, check=True).stdout
         with tempfile.TemporaryDirectory() as snapshot:
             with tarfile.open(fileobj=io.BytesIO(archive)) as tar:
                 tar.extractall(snapshot)
-            with patch.object(compiler_v2, "_KERNEL_DIR", str(Path(snapshot) / kernels)):
+            spec = importlib.util.spec_from_file_location(
+                "CelerisLab.cuda._compiler_a135252", Path(snapshot) / renderer)
+            compiler = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(compiler)
+            with patch.object(compiler, "_KERNEL_DIR", str(Path(snapshot) / kernels)):
                 for size in (128, 256):
                     with self.subTest(size=size):
                         cfg = replace(run_case.config(size, 100), nx=10, ny=10)
                         cfg.validate()
-                        root = compiler_v2.generate_config(cfg)
+                        root = compiler.generate_config(cfg)
                         try:
                             actual = json.loads((Path(root) / ".celeris-build").read_text())
                             expected = build_metadata(size)
                             self.assertEqual(actual, {key: expected[key] for key in
                                                       ("source_sha256", "config", "n_objects")})
                         finally:
-                            compiler_v2.cleanup_build_dir(root)
+                            compiler.cleanup_build_dir(root)
 
     def test_source_preflight_requires_clean_exact_revision_and_tree(self):
         import oracle