fix(preprocess): restrict DWH root claims to writers

harness/tests/test_dwh_preprocess_job.py

@@ -6,6 +6,7 @@ from typer.testing import CliRunner
 
 from tht.cli import app
 from tht.jobs.dwh_pipeline import DwhPreprocessPipeline
+from tht.jobs.dwh_pipeline import active_generation_dir, config_dwh_binding
 from tht.jobs.dwh_pipeline import resolve_dwh_snapshot
 from tht.jobs.dwh_pipeline import lease_dwh_snapshot
 from tht.jobs.locking import _lock_name
@@ -30,6 +31,94 @@ def test_dwh_and_evidence_jobs_have_distinct_lock_names():
     assert _lock_name("demo", "dwh") != _lock_name("demo", "evidence")
 
 
+def test_unowned_reads_fail_closed_without_creating_any_files(tmp_path):
+    import pytest
+
+    cfg = snapshot_config(tmp_path)
+    with pytest.raises(Exception, match="not initialized"):
+        resolve_dwh_snapshot(cfg)
+    with pytest.raises(Exception, match="not initialized"):
+        with lease_dwh_snapshot(cfg):
+            pass
+    assert not (tmp_path / ".tht-dwh").exists()
+
+
+def test_writer_claim_allows_only_lock_and_empty_generations(tmp_path):
+    import pytest
+
+    for name, make_entry in (
+        ("unexpected", lambda root: (root / "unexpected").write_text("x")),
+        ("stale-temp", lambda root: (root / ".OWNER.json.stale.tmp").write_text("x")),
+        ("unexpected-dir", lambda root: (root / "other").mkdir()),
+    ):
+        root = tmp_path / name / ".tht-dwh"
+        root.mkdir(parents=True, mode=0o700)
+        make_entry(root)
+        calls = []
+        pipeline = DwhPreprocessPipeline(
+            workspace_id="demo", workspace_root=root.parent,
+            config_fingerprint=FP, input_fingerprint=FP,
+            introspect=lambda output: calls.append("called"),
+            build_lsh=lambda physical, output: None,
+        )
+        with pytest.raises(Exception, match="unbound"):
+            pipeline.run()
+        assert calls == []
+        assert not (root / "OWNER.json").exists()
+
+    allowed = tmp_path / "allowed"
+    (allowed / ".tht-dwh" / "generations").mkdir(parents=True, mode=0o700)
+    report = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=allowed,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=lambda output: output.write_text("catalog"),
+        build_lsh=lambda physical, output: _write_lsh([], physical, output),
+    ).run()
+    assert report.status == "succeeded"
+
+
+def test_writer_rejects_unbound_legacy_artifacts_before_building(tmp_path):
+    import pytest
+
+    legacy = tmp_path / "artifacts" / "mschema" / "physical.yaml"
+    legacy.parent.mkdir(parents=True)
+    legacy.write_text("legacy")
+    calls = []
+    pipeline = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=tmp_path,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=lambda output: calls.append("called"),
+        build_lsh=lambda physical, output: None,
+        current_physical=legacy,
+    )
+    with pytest.raises(Exception, match="legacy artifacts are unbound"):
+        pipeline.run()
+    assert calls == []
+    assert not (tmp_path / ".tht-dwh" / "OWNER.json").exists()
+
+
+def test_owner_requires_exact_read_only_owner_mode_and_active_requires_binding(tmp_path):
+    import pytest
+
+    pipeline = DwhPreprocessPipeline(
+        workspace_id="demo", workspace_root=tmp_path,
+        config_fingerprint=FP, input_fingerprint=FP,
+        introspect=lambda output: output.write_text("catalog"),
+        build_lsh=lambda physical, output: _write_lsh([], physical, output),
+    )
+    pipeline.run()
+    cfg = snapshot_config(tmp_path)
+    binding = config_dwh_binding(cfg)
+    assert active_generation_dir(tmp_path, binding) is not None
+    with pytest.raises(Exception, match="different workspace configuration"):
+        active_generation_dir(tmp_path, {**binding, "workspace_id": "other"})
+
+    marker = tmp_path / ".tht-dwh" / "OWNER.json"
+    marker.chmod(0o440)
+    with pytest.raises(Exception, match="ownership marker"):
+        resolve_dwh_snapshot(cfg)
+
+
 def test_selected_dwh_stages_run_in_declared_order(tmp_path):
     calls = []
     pipeline = DwhPreprocessPipeline(

harness/tests/test_search_pack.py

@@ -5,6 +5,8 @@ from types import SimpleNamespace
 from typer.testing import CliRunner
 
 from tht.cli import app
+from tht.config import load_config
+from tht.jobs.dwh_pipeline import DwhPreprocessPipeline, config_dwh_binding
 from tht.mschema.models import ColumnPhysical, PhysicalSchema, TablePhysical
 from tht.vectorstore.embeddings import EmbeddingsError
 
@@ -43,11 +45,11 @@ class _FakeSearcher:
 
 
 def _workspace(tmp_path, with_session=None):
-    PhysicalSchema(
+    physical = PhysicalSchema(
         database="d", schema="s", introspected_at=datetime(2026, 1, 1),
         tables={"fact_ablazione": TablePhysical(
             comment="Ablazioni", columns={"cod_paz": ColumnPhysical(type="bigint")})},
-    ).to_yaml(tmp_path / "artifacts" / "mschema" / "physical.yaml")
+    )
     cfg = tmp_path / "workspace.yaml"
     cfg.write_text(
         "database: {database: d, schema: s, user: u, password: p, transport: direct}\n"
@@ -56,6 +58,18 @@ def _workspace(tmp_path, with_session=None):
         f"paths: {{artifacts: {tmp_path/'artifacts'}, indexes: {tmp_path/'i'}, "
         f"sessions: {tmp_path/'sessions'}}}\n"
     )
+    binding = config_dwh_binding(load_config(cfg))
+    DwhPreprocessPipeline(
+        workspace_id=binding["workspace_id"], workspace_root=tmp_path,
+        config_fingerprint=binding["config_fingerprint"],
+        input_fingerprint=binding["input_fingerprint"],
+        introspect=lambda output: physical.to_yaml(output),
+        build_lsh=lambda _physical, output: [
+            (output / name).write_text("index")
+            for name in ("s_lsh.pkl", "s_minhashes.pkl", "s_meta.json")
+        ],
+        lsh_filenames=("s_lsh.pkl", "s_minhashes.pkl", "s_meta.json"),
+    ).run()
     if with_session:
         sdir = tmp_path / "sessions" / with_session
         sdir.mkdir(parents=True)

harness/tht/cli/lsh_cmd.py

@@ -77,9 +77,9 @@ def build_cmd(config: Path = CONFIG_OPT) -> None:
         )
         raise typer.Exit(code=1)
     typer.echo("Estrazione valori (i più frequenti) dalle colonne testuali eligible...")
-    from tht.jobs.dwh_pipeline import active_generation_dir
+    from tht.jobs.dwh_pipeline import resolve_dwh_snapshot
 
-    if active_generation_dir(cfg.paths.artifacts.parent) is None:
+    if resolve_dwh_snapshot(cfg).generation is None:
         minhashes, skipped, truncated, values = build_lsh_artifacts(cfg, verbose=True)
         n_values = sum(len(v) for table in values.values() for v in table.values())
         n_columns = sum(len(table) for table in values.values())

harness/tht/cli/preprocess_cmd.py

@@ -19,15 +19,14 @@ def run_dwh_from_config(
     config: Path, *, steps: tuple[str, ...], resume: str | None = None,
 ):
     from tht.cli.lsh_cmd import build_lsh_artifacts
-    from tht.cli.schema_cmd import _load_config_or_exit, physical_path, refresh_catalog
+    from tht.cli.schema_cmd import _load_config_or_exit, refresh_catalog
     from tht.jobs.dwh_pipeline import (
-        DwhPreprocessPipeline, active_generation_dir, config_dwh_binding,
+        DwhPreprocessPipeline, config_dwh_binding,
     )
 
     cfg = _load_config_or_exit(config)
     binding = config_dwh_binding(cfg)
     workspace_root = cfg.paths.artifacts.parent
-    active = active_generation_dir(workspace_root)
     lsh_names = (
         f"{cfg.database.db_schema}_lsh.pkl",
         f"{cfg.database.db_schema}_minhashes.pkl",
@@ -43,8 +42,8 @@ def run_dwh_from_config(
             cfg, physical_file=physical, output_dir=output
         ),
         lsh_filenames=lsh_names,
-        current_physical=physical_path(cfg),
+        current_physical=cfg.paths.artifacts / "mschema" / "physical.yaml",
-        current_lsh_dir=active if active is not None else cfg.paths.indexes / "lsh",
+        current_lsh_dir=cfg.paths.indexes / "lsh",
     )
     return pipeline.run(steps, resume_run_id=resume)
 

harness/tht/cli/schema_cmd.py

@@ -39,6 +39,8 @@ def _load_config_or_exit(config: Path):
 def physical_path(cfg) -> Path:
     from tht.jobs.dwh_pipeline import resolve_dwh_snapshot
 
+    if not (cfg.paths.artifacts.parent / ".tht-dwh").exists():
+        return cfg.paths.artifacts / "mschema" / "physical.yaml"
     return resolve_dwh_snapshot(cfg).physical
 
 
@@ -92,9 +94,9 @@ def introspect_cmd(
             )
             return
     try:
-        from tht.jobs.dwh_pipeline import active_generation_dir
+        from tht.jobs.dwh_pipeline import resolve_dwh_snapshot
 
-        if active_generation_dir(cfg.paths.artifacts.parent) is None:
+        if resolve_dwh_snapshot(cfg).generation is None:
             phys = refresh_catalog(cfg)
         else:
             from tht.cli.preprocess_cmd import run_dwh_from_config

harness/tht/jobs/dwh_pipeline.py

@@ -51,7 +51,22 @@ def _binding_digest(binding: dict[str, str]) -> str:
 def _read_root_binding(workspace_root: Path) -> dict[str, str]:
     marker = workspace_root / ".tht-dwh" / OWNER_MARKER
     try:
-        payload = json.loads(_read_owned(marker, readonly=True).decode("utf-8"))
+        fd = os.open(marker, os.O_RDONLY | os.O_NOFOLLOW)
+        try:
+            info = os.fstat(fd)
+            if (
+                not stat.S_ISREG(info.st_mode)
+                or info.st_uid != os.getuid()
+                or info.st_nlink != 1
+                or stat.S_IMODE(info.st_mode) != 0o400
+            ):
+                raise OSError("unsafe DWH ownership marker")
+            chunks = []
+            while chunk := os.read(fd, 1024 * 1024):
+                chunks.append(chunk)
+        finally:
+            os.close(fd)
+        payload = json.loads(b"".join(chunks).decode("utf-8"))
         binding = payload["binding"]
         if (
             payload.get("schema_version") != 1
@@ -81,6 +96,9 @@ def _validate_root_binding(workspace_root: Path, expected: dict[str, str]) -> No
         raise CorruptCheckpointError("DWH generations directory is invalid") from error
     else:
         try:
+            info = os.fstat(generations_fd)
+            if info.st_uid != os.getuid() or stat.S_IMODE(info.st_mode) != 0o700:
+                raise OSError("unsafe DWH generations directory")
             generation_entries = os.listdir(generations_fd)
         finally:
             os.close(generations_fd)
@@ -94,25 +112,31 @@ def _claim_or_validate_root_binding(workspace_root: Path, binding: dict[str, str
     if marker.exists() or marker.is_symlink():
         _validate_root_binding(workspace_root, binding)
         return
-    generations = root / "generations"
+    root_fd = os.open(root, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW)
-    generations_nonempty = False
     try:
-        generations_fd = os.open(
+        entries = set(os.listdir(root_fd))
-            generations, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW
+        if not entries <= {"generation.lock", "generations"} or "generation.lock" not in entries:
-        )
+            raise CorruptCheckpointError(
-    except FileNotFoundError:
+                "DWH artifacts are unbound; migrate them explicitly or use an empty root"
-        pass
+            )
+        if "generations" in entries:
+            generations_fd = os.open(
+                "generations", os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW, dir_fd=root_fd
+            )
+            try:
+                info = os.fstat(generations_fd)
+                if info.st_uid != os.getuid() or stat.S_IMODE(info.st_mode) != 0o700:
+                    raise OSError("unsafe DWH generations directory")
+                if os.listdir(generations_fd):
+                    raise CorruptCheckpointError(
+                        "DWH artifacts are unbound; migrate them explicitly or use an empty root"
+                    )
+            finally:
+                os.close(generations_fd)
     except OSError as error:
-        raise CorruptCheckpointError("DWH generations directory is invalid") from error
+        raise CorruptCheckpointError("DWH workspace root is invalid") from error
-    else:
+    finally:
-        try:
+        os.close(root_fd)
-            generations_nonempty = bool(os.listdir(generations_fd))
-        finally:
-            os.close(generations_fd)
-    if (root / "ACTIVE").exists() or generations_nonempty:
-        raise CorruptCheckpointError(
-            "DWH artifacts are unbound; migrate them explicitly or use an empty root"
-        )
     payload = {
         "schema_version": 1,
         "binding": binding,
@@ -148,13 +172,9 @@ class DwhSnapshotLease:
 
     def __enter__(self) -> DwhArtifactSnapshot:
         binding = config_dwh_binding(self.cfg)
-        claim_fd = _acquire_generation_lock(self.cfg.paths.artifacts.parent, exclusive=True)
+        self._fd = _acquire_existing_generation_lock(
-        try:
+            self.cfg.paths.artifacts.parent, exclusive=False
-            _claim_or_validate_root_binding(self.cfg.paths.artifacts.parent, binding)
+        )
-        finally:
-            fcntl.flock(claim_fd, fcntl.LOCK_UN)
-            os.close(claim_fd)
-        self._fd = _acquire_generation_lock(self.cfg.paths.artifacts.parent, exclusive=False)
         try:
             self.snapshot = _resolve_dwh_snapshot_locked(self.cfg, binding)
             return self.snapshot
@@ -179,7 +199,12 @@ def _acquire_generation_lock(workspace_root: Path, *, exclusive: bool) -> int:
     fd = os.open(root / "generation.lock", os.O_RDWR | os.O_CREAT | os.O_NOFOLLOW, 0o600)
     try:
         info = os.fstat(fd)
-        if not stat.S_ISREG(info.st_mode) or info.st_uid != os.getuid() or info.st_nlink != 1:
+        if (
+            not stat.S_ISREG(info.st_mode)
+            or info.st_uid != os.getuid()
+            or info.st_nlink != 1
+            or stat.S_IMODE(info.st_mode) != 0o600
+        ):
             raise OSError("unsafe DWH generation lock")
         fcntl.flock(fd, fcntl.LOCK_EX if exclusive else fcntl.LOCK_SH)
         return fd
@@ -188,6 +213,37 @@ def _acquire_generation_lock(workspace_root: Path, *, exclusive: bool) -> int:
         raise
 
 
+def _acquire_existing_generation_lock(workspace_root: Path, *, exclusive: bool) -> int:
+    root = workspace_root / ".tht-dwh"
+    try:
+        root_fd = os.open(root, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW)
+        try:
+            root_info = os.fstat(root_fd)
+            if root_info.st_uid != os.getuid() or stat.S_IMODE(root_info.st_mode) != 0o700:
+                raise OSError("unsafe DWH workspace root")
+            fd = os.open("generation.lock", os.O_RDWR | os.O_NOFOLLOW, dir_fd=root_fd)
+        finally:
+            os.close(root_fd)
+        try:
+            info = os.fstat(fd)
+            if (
+                not stat.S_ISREG(info.st_mode)
+                or info.st_uid != os.getuid()
+                or info.st_nlink != 1
+                or stat.S_IMODE(info.st_mode) != 0o600
+            ):
+                raise OSError("unsafe DWH generation lock")
+            fcntl.flock(fd, fcntl.LOCK_EX if exclusive else fcntl.LOCK_SH)
+            return fd
+        except BaseException:
+            os.close(fd)
+            raise
+    except OSError as error:
+        raise CorruptCheckpointError(
+            "DWH workspace ownership is not initialized; run preprocessing first"
+        ) from error
+
+
 def _digest(path: Path) -> str:
     return hashlib.sha256(path.read_bytes()).hexdigest()
 
@@ -289,13 +345,9 @@ def validate_generation(
 
 def resolve_dwh_snapshot(cfg) -> DwhArtifactSnapshot:
     binding = config_dwh_binding(cfg)
-    claim_fd = _acquire_generation_lock(cfg.paths.artifacts.parent, exclusive=True)
+    lease_fd = _acquire_existing_generation_lock(
-    try:
+        cfg.paths.artifacts.parent, exclusive=False
-        _claim_or_validate_root_binding(cfg.paths.artifacts.parent, binding)
+    )
-    finally:
-        fcntl.flock(claim_fd, fcntl.LOCK_UN)
-        os.close(claim_fd)
-    lease_fd = _acquire_generation_lock(cfg.paths.artifacts.parent, exclusive=False)
     try:
         return _resolve_dwh_snapshot_locked(cfg, binding)
     finally:
@@ -307,7 +359,7 @@ def _resolve_dwh_snapshot_locked(
     cfg, binding: dict[str, str],
 ) -> DwhArtifactSnapshot:
     _validate_root_binding(cfg.paths.artifacts.parent, binding)
-    target = active_generation_dir(cfg.paths.artifacts.parent)
+    target = _active_generation_dir_locked(cfg.paths.artifacts.parent, binding)
     if target is None:
         return DwhArtifactSnapshot(
             None, cfg.paths.artifacts / "mschema" / "physical.yaml", cfg.paths.indexes / "lsh"
@@ -316,7 +368,21 @@ def _resolve_dwh_snapshot_locked(
     return DwhArtifactSnapshot(target.name, target / "physical.yaml", target)
 
 
-def active_generation_dir(workspace_root: Path) -> Path | None:
+def active_generation_dir(
+    workspace_root: Path, expected_binding: dict[str, str]
+) -> Path | None:
+    lease_fd = _acquire_existing_generation_lock(workspace_root, exclusive=False)
+    try:
+        return _active_generation_dir_locked(workspace_root, expected_binding)
+    finally:
+        fcntl.flock(lease_fd, fcntl.LOCK_UN)
+        os.close(lease_fd)
+
+
+def _active_generation_dir_locked(
+    workspace_root: Path, expected_binding: dict[str, str]
+) -> Path | None:
+    _validate_root_binding(workspace_root, expected_binding)
     pointer = workspace_root / ".tht-dwh" / "ACTIVE"
     try:
         generation = _read_owned(pointer, readonly=False).decode("utf-8").strip()
@@ -329,6 +395,7 @@ def active_generation_dir(workspace_root: Path) -> Path | None:
     target = pointer.parent / "generations" / generation
     if not target.is_dir() or target.is_symlink():
         raise CorruptCheckpointError("active DWH generation is missing")
+    validate_generation(target, expected_binding)
     return target
 
 
@@ -381,7 +448,7 @@ class DwhPreprocessPipeline:
 
     def _assert_active_binding(self) -> None:
         _validate_root_binding(self.workspace_root, self.binding)
-        active = active_generation_dir(self.workspace_root)
+        active = _active_generation_dir_locked(self.workspace_root, self.binding)
         if active is not None:
             validate_generation(active, self.binding)
 
@@ -391,8 +458,13 @@ class DwhPreprocessPipeline:
         self._validate_steps(steps)
         lease_fd = _acquire_generation_lock(self.workspace_root, exclusive=True)
         try:
+            self._assert_no_legacy_artifacts()
             _claim_or_validate_root_binding(self.workspace_root, self.binding)
             self._assert_active_binding()
+            active = _active_generation_dir_locked(self.workspace_root, self.binding)
+            if active is not None:
+                self.current_physical = active / "physical.yaml"
+                self.current_lsh_dir = active
         finally:
             fcntl.flock(lease_fd, fcntl.LOCK_UN)
             os.close(lease_fd)
@@ -454,7 +526,7 @@ class DwhPreprocessPipeline:
             return set()
         target = self.workspace_root / ".tht-dwh" / "generations" / source.run_id
         validate_generation(target, self.binding)
-        active = active_generation_dir(self.workspace_root)
+        active = active_generation_dir(self.workspace_root, self.binding)
         if active != target:
             raise CorruptCheckpointError("sealed DWH publication is not ACTIVE")
         self._validate_published(target, run_dir / "artifacts", running.artifact_files)
@@ -484,6 +556,19 @@ class DwhPreprocessPipeline:
             raise CorruptCheckpointError("resume artifact manifest is invalid") from error
         self._validate_published(target, run_dir / "artifacts", required)
 
+    def _assert_no_legacy_artifacts(self) -> None:
+        marker = self.workspace_root / ".tht-dwh" / OWNER_MARKER
+        if marker.exists() or marker.is_symlink():
+            return
+        legacy_physical = self.current_physical is not None and self.current_physical.exists()
+        legacy_lsh = self.current_lsh_dir is not None and any(
+            (self.current_lsh_dir / name).exists() for name in self.lsh_filenames
+        )
+        if legacy_physical or legacy_lsh:
+            raise CorruptCheckpointError(
+                "DWH legacy artifacts are unbound; migrate them explicitly or use an empty root"
+            )
+
     @staticmethod
     def _artifacts(context: JobContext) -> Path:
         root = context.run_dir / "artifacts"
@@ -630,7 +715,7 @@ class DwhPreprocessPipeline:
         if not root.exists():
             return
         _validate_root_binding(self.workspace_root, self.binding)
-        active = active_generation_dir(self.workspace_root)
+        active = _active_generation_dir_locked(self.workspace_root, self.binding)
         if active is not None:
             validate_generation(active, self.binding)
         active_name = active.name if active else None