fix(preprocess): publish DWH artifacts atomically

harness/tests/test_dwh_preprocess_job.py

@@ -1,5 +1,6 @@
 import hashlib
 import json
+from pathlib import Path
 
 from typer.testing import CliRunner
 
@@ -22,8 +23,8 @@ def test_selected_dwh_stages_run_in_declared_order(tmp_path):
         workspace_root=tmp_path,
         config_fingerprint=FP,
         input_fingerprint=FP,
-        introspect=lambda: calls.append("introspect"),
-        build_lsh=lambda: calls.append("lsh"),
+        introspect=lambda output: (calls.append("introspect"), output.write_text("catalog")),
+        build_lsh=lambda physical, output: _write_lsh(calls, physical, output),
     )
 
     report = pipeline.run(("introspect", "lsh"))
@@ -31,6 +32,19 @@ def test_selected_dwh_stages_run_in_declared_order(tmp_path):
     assert report.status == "succeeded"
     assert calls == ["introspect", "lsh"]
     assert [stage.name for stage in report.stages] == ["introspect", "lsh"]
+    active = (tmp_path / ".tht-dwh" / "ACTIVE").read_text().strip()
+    published = tmp_path / ".tht-dwh" / "generations" / active
+    assert (published / "physical.yaml").read_text() == "catalog"
+    assert sorted(path.name for path in published.iterdir()) == [
+        "demo_lsh.pkl", "demo_meta.json", "demo_minhashes.pkl", "physical.yaml"
+    ]
+
+
+def _write_lsh(calls, physical: Path, output: Path):
+    calls.append("lsh")
+    assert physical.read_text() == "catalog"
+    for name in ("demo_lsh.pkl", "demo_minhashes.pkl", "demo_meta.json"):
+        (output / name).write_text(name)
 
 
 def test_preprocess_dwh_json_is_pristine(monkeypatch, tmp_path):
@@ -81,3 +95,47 @@ def test_preprocess_dwh_rejects_unknown_or_duplicate_steps(monkeypatch, tmp_path
         assert response.exit_code == 2
         assert json.loads(response.output)["status"] == "failed"
     assert called is False
+
+
+def test_failed_multi_file_build_never_replaces_active_generation(tmp_path):
+    def catalog(output):
+        output.write_text("old-catalog")
+
+    first = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=tmp_path,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=catalog,
+        build_lsh=lambda physical, output: [
+            (output / name).write_text(name)
+            for name in ("demo_lsh.pkl", "demo_minhashes.pkl", "demo_meta.json")
+        ],
+    ).run(("introspect", "lsh"))
+    assert first.status == "succeeded"
+    old_active = (tmp_path / ".tht-dwh" / "ACTIVE").read_text()
+
+    def partial_lsh(physical, output):
+        (output / "demo_lsh.pkl").write_text("new-but-partial")
+        raise RuntimeError("crash between LSH files")
+
+    failed = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=tmp_path,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=lambda output: output.write_text("new-catalog"),
+        build_lsh=partial_lsh,
+    ).run(("introspect", "lsh"))
+
+    assert failed.status == "failed"
+    assert (tmp_path / ".tht-dwh" / "ACTIVE").read_text() == old_active
+
+    resumed = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=tmp_path,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=lambda output: (_ for _ in ()).throw(
+            AssertionError("completed introspection must not repeat")
+        ),
+        build_lsh=lambda physical, output: [
+            (output / name).write_text("recovered")
+            for name in ("demo_lsh.pkl", "demo_minhashes.pkl", "demo_meta.json")
+        ],
+    ).run(("introspect", "lsh"), resume_run_id=failed.run_id)
+    assert resumed.status == "succeeded"