Establish Milestone 0 compatibility and quality gates

tests/test_adapter_contract.py

@@ -47,6 +47,7 @@ from docforge.models import (
     RenderConfig,
     RenderView,
 )
+from docforge.viewer_manager import ViewerManagerClient
 from docforge.visualization import VisualizationIndexSnapshot
 
 
@@ -236,6 +237,13 @@ class OverlappingIncrementalLoader(IncrementalLoader):
         return self.assemble_projection(manifest, contributions).projection
 
 
+class NonLogicIncrementalLoader(IncrementalLoader):
+    """Exercise non-AST incremental caching without publishing function Logic."""
+
+    def extract_source(self, source: AdapterSource) -> AdapterSourceProjection:
+        return replace(super().extract_source(source), logic=())
+
+
 class AdapterContractTests(unittest.TestCase):
     def projection(self, root: Path) -> AdapterProjection:
         foundation = Node(
@@ -561,6 +569,60 @@ class AdapterContractTests(unittest.TestCase):
             self.assertEqual("adapter_policy_forbids_logic", captured.exception.code)
             self.assertFalse(project.descriptor.index_path.exists())
 
+    def test_no_ast_index_accepts_legacy_and_non_logic_incremental_adapters(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory).resolve()
+            legacy = AdapterProject(
+                Loader(self.projection(root)),
+                cache_root=root / ".cache" / "legacy-no-ast",
+            )
+            legacy_index = ProjectIndex(legacy, allow_logic=False)
+            self.assertEqual(2, legacy_index.build()["node_count"])
+            self.assertEqual(
+                "guide.workflow",
+                legacy_index.get_node("guide.workflow")["node"]["node_id"],
+            )
+
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory).resolve()
+            loader = NonLogicIncrementalLoader(root)
+            project = AdapterProject(
+                loader,
+                cache_root=root / ".cache" / "incremental-no-ast",
+            )
+            index = ProjectIndex(project, allow_logic=False)
+            first = index.build()
+            self.assertEqual(2, first["build"]["reparsed_sources"])
+            loader.extract_calls.clear()
+
+            second = index.build()
+
+            self.assertEqual([], loader.extract_calls)
+            self.assertEqual(2, second["build"]["cache_hits"])
+            self.assertEqual(0, second["build"]["reparsed_sources"])
+            self.assertEqual(0, second["logic_projection_count"])
+
+    def test_no_ast_rejects_preexisting_logic_index_and_viewer_snapshot(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory).resolve()
+            project = AdapterProject(
+                IncrementalLoader(root),
+                cache_root=root / ".cache" / "preexisting-logic",
+            )
+            ProjectIndex(project).build()
+            preserved = ProjectIndex(project, allow_logic=False)
+
+            with self.assertRaises(DocForgeError) as checked:
+                preserved.check(verify_rows=False)
+            self.assertEqual("adapter_policy_forbids_logic", checked.exception.code)
+
+            with self.assertRaises(DocForgeError) as viewed:
+                ViewerManagerClient(
+                    preserved,
+                    state_path=root / ".cache" / "viewer-state.json",
+                ).start()
+            self.assertEqual("adapter_policy_forbids_logic", viewed.exception.code)
+
     def test_fast_incremental_reads_reverify_a_changed_index_file(self) -> None:
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory).resolve()