fix(vector_store): carry weaviate offset fallback across pages, raise on truncation

VectorStore cannot actually migrate to or from qdrant yet. _init_backend_store constructs QdrantStore without connecting or selecting a collection, so reads raise a Collection not initialized error, and the facade store_vectors dispatches only to add/add_vectors while QdrantStore exposes insert_vectors, so writes raise NotImplementedError.

Both are pre-existing facade gaps that nothing had exposed, since migrate previously only allowed faiss/sqlite/pgvector. Adding qdrant to the allowlist claimed support that does not work end to end, so it is removed along with the dimension inference that only fires for backends missing a .dimension attribute. Tracked separately; this PR keeps just the iter_all primitive.

semantica/vector_store/qdrant_store.py

@@ -604,6 +604,62 @@ class QdrantStore:
             self.logger.warning(f"Failed to scroll Qdrant points by metadata filter: {e}")
             return []
 
+    def iter_all(self, batch_size: int = 500):
+        """
+        Iterate over every stored point using Qdrant's native scroll cursor.
+
+        Qdrant paginates by point-ID cursor, not by row offset, so this is
+        exposed instead of scan_vectors(offset, limit). An integer passed to
+        scroll()'s offset is a point ID rather than a rank, so there is no way
+        to seek to "the Nth record" without walking from the start.
+        VectorStore.iter_vectors() prefers this method when it is present.
+
+        Assumes a single unnamed vector per point, matching how insert_vectors()
+        writes them and how get_vector() reads them back. Collections configured
+        with named or multi-vectors are not handled here.
+
+        Args:
+            batch_size: Points to request per scroll call
+
+        Yields:
+            Result dicts with 'id', 'metadata', and 'vector', in scroll order
+
+        Raises:
+            ProcessingError: If the collection or client is not initialized.
+                Errors are raised rather than swallowed because a scan that
+                silently yields nothing is indistinguishable from an empty
+                source, which would let a caller such as `store migrate`
+                report success having copied nothing (issue #1083).
+        """
+        if self.collection is None or self.client is None or not QDRANT_AVAILABLE:
+            raise ProcessingError(
+                "Collection not initialized. Call create_collection() or get_collection() first."
+            )
+
+        next_offset = None
+        while True:
+            records, next_offset = self.client.scroll(
+                collection_name=self.collection.collection_name,
+                limit=batch_size,
+                offset=next_offset,
+                with_payload=True,
+                with_vectors=True,
+            )
+
+            for rec in records:
+                yield {
+                    "id": str(rec.id),
+                    "metadata": rec.payload or {},
+                    "vector": np.array(rec.vector) if rec.vector is not None else None,
+                }
+
+            # The final page can carry records while already reporting no next
+            # cursor, so those records are yielded above before stopping here.
+            # Calling scroll() again with offset=None would restart from the
+            # beginning rather than continue past the end.
+            if next_offset is None or not records:
+                return
+
     def delete_vectors(
         self, point_ids: List[Union[str, int]], **options
     ) -> Dict[str, Any]:

semantica/vector_store/vector_store.py

@@ -867,12 +867,25 @@ class VectorStore:
         """
         Iterate over every stored vector, one page at a time.
 
+        Backends whose native pagination is cursor based (Qdrant, Pinecone,
+        Milvus, Weaviate) cannot honestly implement the positional
+        scan_vectors(offset, limit) contract, so they expose iter_all()
+        instead and it is preferred here when present. Backends with real
+        positional access (inmemory, FAISS, SQLite-vec, PgVector) fall
+        through to the offset loop below.
+
         Args:
-            batch_size: Number of vectors to fetch per underlying scan_vectors() call
+            batch_size: Number of vectors to fetch per underlying call
 
         Yields:
             Result dicts with 'id', 'metadata', and 'vector', in scan order
         """
+        if self.backend != "inmemory" and self._backend_store is not None:
+            iter_all = getattr(self._backend_store, "iter_all", None)
+            if callable(iter_all):
+                yield from iter_all(batch_size=batch_size)
+                return
+
         offset = 0
         while True:
             page = self.scan_vectors(offset=offset, limit=batch_size)

semantica/vector_store/weaviate_store.py

@@ -611,6 +611,115 @@ class WeaviateStore:
             self.logger.warning(f"Failed to fetch Weaviate objects by metadata filter: {e}")
             return results if results else []
 
+    def iter_all(self, batch_size: int = 500):
+        """
+        Iterate over every stored object using Weaviate's UUID cursor.
+
+        Paginates by the last object's UUID rather than a row offset, which is
+        why this exists instead of scan_vectors(offset, limit).
+
+        Assumes a single unnamed vector per object, as get_vector() and
+        filter_by_metadata() already do. Named-vector collections return a
+        mapping and are not handled.
+
+        Args:
+            batch_size: Objects to request per fetch_objects() call
+
+        Yields:
+            Result dicts with 'id', 'metadata', and 'vector', in cursor order
+
+        Raises:
+            ProcessingError: If the collection is not initialized, or if the
+                scan cannot advance past a full page.
+        """
+        if self.collection is None or not WEAVIATE_AVAILABLE:
+            raise ProcessingError(
+                "Collection not initialized. Call get_collection() first."
+            )
+
+        after_cursor = None
+        scanned_count = 0
+        # Degrades cursor -> offset -> single_page as the client rejects each
+        # form. Tracked across iterations, not just inside the except branch,
+        # or later pages go out with no pagination argument at all.
+        mode = "cursor"
+
+        while True:
+            kwargs = {"limit": batch_size, "include_vector": True}
+            if mode == "cursor" and after_cursor is not None:
+                kwargs["after"] = after_cursor
+            elif mode == "offset":
+                kwargs["offset"] = scanned_count
+
+            try:
+                objs = self.collection.query.fetch_objects(**kwargs)
+            except TypeError:
+                if mode == "cursor" and "after" in kwargs:
+                    mode = "offset"
+                    kwargs.pop("after", None)
+                    kwargs["offset"] = scanned_count
+                    try:
+                        objs = self.collection.query.fetch_objects(**kwargs)
+                    except TypeError:
+                        mode = "single_page"
+                        kwargs.pop("offset", None)
+                        objs = self.collection.query.fetch_objects(**kwargs)
+                elif mode == "offset":
+                    mode = "single_page"
+                    kwargs.pop("offset", None)
+                    objs = self.collection.query.fetch_objects(**kwargs)
+                else:
+                    raise
+
+            batch_objects = getattr(objs, "objects", None) if objs else None
+            if not batch_objects:
+                return
+
+            for obj in batch_objects:
+                obj_uuid = getattr(obj, "uuid", None)
+                raw_vector = getattr(obj, "vector", None)
+                yield {
+                    "id": str(obj_uuid) if obj_uuid is not None else None,
+                    "metadata": getattr(obj, "properties", None) or {},
+                    "vector": (
+                        np.array(raw_vector)
+                        if raw_vector is not None and len(raw_vector) > 0
+                        else None
+                    ),
+                }
+
+            scanned_count += len(batch_objects)
+
+            # Past this point the page was full, so failing to advance is
+            # truncation rather than completion.
+            if len(batch_objects) < batch_size:
+                return
+
+            if mode == "single_page":
+                raise ProcessingError(
+                    "This Weaviate client accepts neither an `after` cursor nor a "
+                    "numeric offset, so the scan cannot advance past the first "
+                    "page. Refusing to return a truncated scan."
+                )
+
+            if mode == "offset":
+                continue
+
+            last_uuid = getattr(batch_objects[-1], "uuid", None)
+            if last_uuid is None:
+                raise ProcessingError(
+                    "The last object of a full Weaviate page has no uuid, so the "
+                    "cursor cannot advance. Refusing to return a truncated scan."
+                )
+
+            next_cursor = str(last_uuid)
+            if next_cursor == after_cursor:
+                raise ProcessingError(
+                    "The Weaviate cursor stopped advancing, so the listing is "
+                    "repeating a page. Refusing to return a truncated scan."
+                )
+            after_cursor = next_cursor
+
 
     def query_vectors(
         self,

tests/vector_store/test_qdrant_store.py

@@ -0,0 +1,152 @@
+"""Tests for QdrantStore.iter_all() cursor enumeration.
+
+Qdrant is not installed in this environment, so these drive the real
+QdrantStore against a MagicMock standing in for the qdrant_client, following
+the pattern already used for qdrant in test_backend_metadata_filtering.py.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import numpy as np
+import pytest
+
+from semantica.utils.exceptions import ProcessingError
+from semantica.vector_store.qdrant_store import QdrantStore
+
+
+def _record(point_id, payload=None, vector=None):
+    """Build a stand-in for a qdrant_client Record."""
+    rec = MagicMock()
+    rec.id = point_id
+    rec.payload = payload
+    rec.vector = vector
+    return rec
+
+
+def _store_with_scroll(*pages):
+    """QdrantStore whose client.scroll() returns the given (records, cursor) pages."""
+    store = QdrantStore()
+    store.client = MagicMock()
+    store.client.scroll.side_effect = list(pages)
+    store.collection = MagicMock()
+    store.collection.collection_name = "test_collection"
+    return store
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_threads_cursor_across_pages():
+    """The next call must continue from the previous page's next_page_offset."""
+    store = _store_with_scroll(
+        ([_record(1), _record(2)], "cursor-1"),
+        ([_record(3)], None),
+    )
+
+    result = list(store.iter_all(batch_size=2))
+
+    assert [item["id"] for item in result] == ["1", "2", "3"]
+    calls = store.client.scroll.call_args_list
+    assert len(calls) == 2
+    assert calls[0][1]["offset"] is None
+    assert calls[0][1]["limit"] == 2
+    assert calls[1][1]["offset"] == "cursor-1"
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_yields_final_page_that_reports_no_next_cursor():
+    """Qdrant can return records and a null cursor on the same page.
+
+    Those records must still be yielded. Treating a null cursor as "stop
+    before this page" would silently drop the tail of every scan.
+    """
+    store = _store_with_scroll(([_record(1), _record(2)], None))
+
+    result = list(store.iter_all(batch_size=10))
+
+    assert [item["id"] for item in result] == ["1", "2"]
+    assert store.client.scroll.call_count == 1
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_converts_records_to_the_shared_result_shape():
+    store = _store_with_scroll(
+        ([_record(7, payload={"tag": "x"}, vector=[0.1, 0.2, 0.3])], None),
+    )
+
+    item = list(store.iter_all())[0]
+
+    assert item["id"] == "7"
+    assert item["metadata"] == {"tag": "x"}
+    np.testing.assert_allclose(item["vector"], np.array([0.1, 0.2, 0.3]))
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_handles_missing_payload_and_vector():
+    store = _store_with_scroll(([_record(1, payload=None, vector=None)], None))
+
+    item = list(store.iter_all())[0]
+
+    assert item["metadata"] == {}
+    assert item["vector"] is None
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_empty_collection_yields_nothing():
+    store = _store_with_scroll(([], None))
+
+    assert list(store.iter_all()) == []
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_stops_on_empty_page_even_with_a_cursor():
+    """Defensive: an empty page ends the scan rather than looping forever."""
+    store = _store_with_scroll(([], "cursor-that-never-clears"))
+
+    assert list(store.iter_all()) == []
+    assert store.client.scroll.call_count == 1
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_raises_when_collection_not_initialized():
+    """Must fail loudly, not yield nothing.
+
+    An empty scan is indistinguishable from an empty source, which would let
+    `store migrate` report success having copied nothing (issue #1083).
+    """
+    store = QdrantStore()
+
+    with pytest.raises(ProcessingError, match="Collection not initialized"):
+        list(store.iter_all())
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", False)
+def test_iter_all_raises_when_qdrant_unavailable():
+    store = QdrantStore()
+    store.client = MagicMock()
+    store.collection = MagicMock()
+
+    with pytest.raises(ProcessingError):
+        list(store.iter_all())
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_propagates_scroll_errors():
+    store = QdrantStore()
+    store.client = MagicMock()
+    store.client.scroll.side_effect = RuntimeError("connection reset")
+    store.collection = MagicMock()
+    store.collection.collection_name = "test_collection"
+
+    with pytest.raises(RuntimeError, match="connection reset"):
+        list(store.iter_all())
+
+
+@patch("semantica.vector_store.qdrant_store.QDRANT_AVAILABLE", True)
+def test_iter_all_requests_payload_and_vectors():
+    store = _store_with_scroll(([], None))
+
+    list(store.iter_all())
+
+    kwargs = store.client.scroll.call_args[1]
+    assert kwargs["with_payload"] is True
+    assert kwargs["with_vectors"] is True
+    assert kwargs["collection_name"] == "test_collection"

tests/vector_store/test_vector_manager_persistent.py

@@ -26,6 +26,7 @@ from unittest.mock import MagicMock, patch
 
 import numpy as np
 
+from semantica.utils.exceptions import ProcessingError
 from semantica.vector_store.vector_store import VectorStore, VectorManager
 
 
@@ -138,6 +139,38 @@ class _NonScanningBackendStore:
     """Fake persistent backend store without any scan capability."""
 
 
+class _IterAllBackendStore:
+    """Fake cursor-based backend store exposing iter_all() but not scan_vectors().
+
+    Mirrors qdrant/pinecone/milvus/weaviate, which cannot honour a positional
+    offset and therefore expose native iteration instead.
+    """
+
+    def __init__(self, items):
+        self._items = items
+        self.batch_sizes = []
+
+    def iter_all(self, batch_size=500):
+        self.batch_sizes.append(batch_size)
+        for item in self._items:
+            yield item
+
+    def scan_vectors(self, offset=0, limit=100):
+        raise AssertionError("scan_vectors() must not be called when iter_all() exists")
+
+
+class _MisShapedIterAllBackendStore:
+    """Backend store whose ``iter_all`` attribute is not callable."""
+
+    iter_all = 42  # plain attribute, not a method
+
+    def __init__(self, items):
+        self._items = items
+
+    def scan_vectors(self, offset=0, limit=100):
+        return self._items[offset:offset + limit]
+
+
 class VectorStoreScanVectorsTests(unittest.TestCase):
     """VectorStore.scan_vectors() / iter_vectors() backend-agnostic accessors."""
 
@@ -192,6 +225,81 @@ class VectorStoreScanVectorsTests(unittest.TestCase):
         self.assertEqual(list(store.iter_vectors(batch_size=2)), [])
 
 
+# ---------------------------------------------------------------------------
+# VectorStore.iter_vectors() preference for a native iter_all()
+# ---------------------------------------------------------------------------
+
+class VectorStoreIterAllDispatchTests(unittest.TestCase):
+    """iter_vectors() prefers a backend's native iter_all() when present.
+
+    Cursor-based backends cannot implement scan_vectors(offset, limit)
+    honestly, so they expose iter_all() instead and iter_vectors() routes to
+    it rather than walking offsets.
+    """
+
+    def _persistent_store(self, backend_store, backend_name="qdrant"):
+        store = VectorStore(backend="inmemory", dimension=2)
+        store.backend = backend_name
+        store._backend_store = backend_store
+        return store
+
+    def test_iter_vectors_uses_iter_all_when_available(self):
+        items = [
+            {"id": "a", "vector": None, "metadata": {"n": 1}},
+            {"id": "b", "vector": None, "metadata": {"n": 2}},
+        ]
+        backend = _IterAllBackendStore(items)
+        store = self._persistent_store(backend)
+
+        self.assertEqual(list(store.iter_vectors(batch_size=7)), items)
+
+    def test_iter_vectors_forwards_batch_size_to_iter_all(self):
+        backend = _IterAllBackendStore([])
+        store = self._persistent_store(backend)
+
+        list(store.iter_vectors(batch_size=32))
+
+        self.assertEqual(backend.batch_sizes, [32])
+
+    def test_iter_vectors_falls_back_to_scan_vectors_without_iter_all(self):
+        items = [{"id": "a", "vector": None, "metadata": {}}]
+        store = self._persistent_store(_ScanningBackendStore(items))
+
+        self.assertEqual(list(store.iter_vectors(batch_size=2)), items)
+
+    def test_iter_vectors_falls_back_when_iter_all_not_callable(self):
+        # A mis-shaped adapter exposing a non-callable ``iter_all`` must not be
+        # invoked; the offset path still has to work. Mirrors the count()
+        # precedent in _MisShapedBackendStore.
+        items = [{"id": "a", "vector": None, "metadata": {}}]
+        store = self._persistent_store(_MisShapedIterAllBackendStore(items))
+
+        self.assertEqual(list(store.iter_vectors(batch_size=2)), items)
+
+    def test_iter_vectors_inmemory_ignores_iter_all(self):
+        store = VectorStore(backend="inmemory", dimension=2)
+        store.store_vectors([np.array([1.0, 0.0])], [{"type": "a"}])
+        store._backend_store = _IterAllBackendStore([{"id": "wrong"}])
+
+        collected = list(store.iter_vectors(batch_size=2))
+
+        self.assertEqual([item["metadata"] for item in collected], [{"type": "a"}])
+
+    def test_iter_vectors_propagates_iter_all_errors(self):
+        # A scan that silently yields nothing is indistinguishable from an
+        # empty source, which would let `store migrate` report success having
+        # copied nothing (issue #1083).
+        class _FailingIterAll:
+            def iter_all(self, batch_size=500):
+                raise ProcessingError("backend unreachable")
+                yield  # pragma: no cover - makes this a generator
+
+        store = self._persistent_store(_FailingIterAll())
+
+        with self.assertRaises(ProcessingError):
+            list(store.iter_vectors(batch_size=2))
+
+
 # ---------------------------------------------------------------------------
 # VectorManager tests — inmemory backend
 # ---------------------------------------------------------------------------

tests/vector_store/test_weaviate_store.py

@@ -0,0 +1,231 @@
+"""Tests for WeaviateStore.iter_all() cursor enumeration.
+
+weaviate-client is not installed in this environment, so these drive the real
+WeaviateStore against MagicMocks, following the pattern already used for
+weaviate in test_backend_metadata_filtering.py.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import numpy as np
+import pytest
+
+from semantica.utils.exceptions import ProcessingError
+from semantica.vector_store.weaviate_store import WeaviateStore
+
+
+def _obj(uuid, properties=None, vector=None):
+    """Stand-in for a weaviate v4 returned object."""
+    obj = MagicMock()
+    obj.uuid = uuid
+    obj.properties = properties
+    obj.vector = vector
+    return obj
+
+
+def _page(objects):
+    """Stand-in for a fetch_objects() response."""
+    response = MagicMock()
+    response.objects = objects
+    return response
+
+
+def _store_with_pages(*pages):
+    store = WeaviateStore()
+    store.collection = MagicMock()
+    store.collection.query.fetch_objects.side_effect = list(pages)
+    return store
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_threads_uuid_cursor_across_pages():
+    """The next page must continue after the last object's UUID."""
+    store = _store_with_pages(
+        _page([_obj("uuid-1"), _obj("uuid-2")]),
+        _page([_obj("uuid-3")]),
+    )
+
+    result = list(store.iter_all(batch_size=2))
+
+    assert [item["id"] for item in result] == ["uuid-1", "uuid-2", "uuid-3"]
+    calls = store.collection.query.fetch_objects.call_args_list
+    assert "after" not in calls[0][1]
+    assert calls[1][1]["after"] == "uuid-2"
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_stops_on_short_page():
+    """A page smaller than batch_size means the collection is exhausted."""
+    store = _store_with_pages(_page([_obj("uuid-1")]))
+
+    result = list(store.iter_all(batch_size=5))
+
+    assert [item["id"] for item in result] == ["uuid-1"]
+    assert store.collection.query.fetch_objects.call_count == 1
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_raises_when_cursor_stops_advancing():
+    """A stalled cursor must terminate, but not quietly: a partial scan reads
+    as a complete one."""
+    store = WeaviateStore()
+    store.collection = MagicMock()
+    store.collection.query.fetch_objects.return_value = _page(
+        [_obj("same-uuid"), _obj("same-uuid")]
+    )
+
+    with pytest.raises(ProcessingError, match="stopped advancing"):
+        list(store.iter_all(batch_size=2))
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_offset_fallback_advances_across_pages():
+    """Regression: the offset was only set inside the except branch, so pages
+    after the fallback went out with no pagination at all and the scan
+    restarted from page one."""
+    store = WeaviateStore()
+    store.collection = MagicMock()
+    calls = []
+
+    def _fetch(**kwargs):
+        calls.append(dict(kwargs))
+        if "after" in kwargs:
+            raise TypeError("unexpected keyword argument 'after'")
+        page_number = len(calls)
+        if page_number < 4:
+            return _page([_obj(f"u{page_number}a"), _obj(f"u{page_number}b")])
+        return _page([_obj("last")])
+
+    store.collection.query.fetch_objects.side_effect = _fetch
+
+    ids = [item["id"] for item in store.iter_all(batch_size=2)]
+
+    assert len(set(ids)) == len(ids), f"duplicate ids means the scan restarted: {ids}"
+    assert [c.get("offset") for c in calls] == [None, None, 2, 4]
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_raises_when_no_pagination_is_supported():
+    """A client rejecting both `after` and `offset` cannot page past the first
+    result."""
+    store = WeaviateStore()
+    store.collection = MagicMock()
+
+    def _fetch(**kwargs):
+        if "after" in kwargs or "offset" in kwargs:
+            raise TypeError("unsupported")
+        return _page([_obj("a"), _obj("b")])
+
+    store.collection.query.fetch_objects.side_effect = _fetch
+
+    with pytest.raises(ProcessingError, match="neither an .after. cursor nor a"):
+        list(store.iter_all(batch_size=2))
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_empty_collection_yields_nothing():
+    store = _store_with_pages(_page([]))
+
+    assert list(store.iter_all()) == []
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_converts_objects_to_the_shared_result_shape():
+    store = _store_with_pages(
+        _page([_obj("uuid-7", properties={"tag": "x"}, vector=[0.1, 0.2, 0.3])]),
+    )
+
+    item = list(store.iter_all())[0]
+
+    assert item["id"] == "uuid-7"
+    assert item["metadata"] == {"tag": "x"}
+    np.testing.assert_allclose(item["vector"], np.array([0.1, 0.2, 0.3]))
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_handles_missing_properties_and_vector():
+    store = _store_with_pages(_page([_obj("uuid-1", properties=None, vector=None)]))
+
+    item = list(store.iter_all())[0]
+
+    assert item["metadata"] == {}
+    assert item["vector"] is None
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_treats_empty_vector_as_none():
+    store = _store_with_pages(_page([_obj("uuid-1", vector=[])]))
+
+    assert list(store.iter_all())[0]["vector"] is None
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_requests_vectors():
+    """Weaviate omits vectors unless include_vector is set."""
+    store = _store_with_pages(_page([]))
+
+    list(store.iter_all(batch_size=64))
+
+    kwargs = store.collection.query.fetch_objects.call_args[1]
+    assert kwargs["include_vector"] is True
+    assert kwargs["limit"] == 64
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_falls_back_to_offset_when_after_unsupported():
+    """Older clients reject `after`; the scan degrades to numeric offset."""
+    store = WeaviateStore()
+    store.collection = MagicMock()
+    seen = {"calls": 0}
+
+    def _fetch(**kwargs):
+        if "after" in kwargs:
+            raise TypeError("unexpected keyword argument 'after'")
+        seen["calls"] += 1
+        if seen["calls"] == 1:
+            return _page([_obj("uuid-1"), _obj("uuid-2")])
+        return _page([_obj("uuid-3")])
+
+    store.collection.query.fetch_objects.side_effect = _fetch
+
+    result = list(store.iter_all(batch_size=2))
+
+    assert [item["id"] for item in result] == ["uuid-1", "uuid-2", "uuid-3"]
+    offsets = [
+        c[1]["offset"]
+        for c in store.collection.query.fetch_objects.call_args_list
+        if "offset" in c[1]
+    ]
+    assert offsets == [2]
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_raises_when_collection_not_initialized():
+    """Must fail loudly, not yield nothing.
+
+    An empty scan is indistinguishable from an empty source, which would let
+    `store migrate` report success having copied nothing (issue #1083).
+    """
+    store = WeaviateStore()
+
+    with pytest.raises(ProcessingError, match="Collection not initialized"):
+        list(store.iter_all())
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", False)
+def test_iter_all_raises_when_weaviate_unavailable():
+    store = WeaviateStore()
+    store.collection = MagicMock()
+
+    with pytest.raises(ProcessingError):
+        list(store.iter_all())
+
+
+@patch("semantica.vector_store.weaviate_store.WEAVIATE_AVAILABLE", True)
+def test_iter_all_propagates_fetch_errors():
+    store = WeaviateStore()
+    store.collection = MagicMock()
+    store.collection.query.fetch_objects.side_effect = RuntimeError("connection reset")
+
+    with pytest.raises(RuntimeError, match="connection reset"):
+        list(store.iter_all())