fix(python): preserve pylance distribution variant

docs/src/python/python.md

@@ -17,6 +17,25 @@ The general flow of using the API is:
 pip install lancedb
 ```
 
+The core package does not require PyLance. When you need access to the underlying
+Lance dataset or GPU-accelerated indexing, add the `pylance` extra to the
+distribution you already installed.
+
+For the standard distribution:
+
+```shell
+pip install "lancedb[pylance]"
+```
+
+For the pre-Haswell compatibility distribution:
+
+```shell
+pip install "lancedb-compat[pylance]"
+```
+
+Use only the extra matching your installed distribution. Do not install both
+distributions because they share the `lancedb` namespace.
+
 The following methods describe the synchronous API client. There
 is also an [asynchronous API client](#connections-asynchronous).
 

python/README.md

@@ -8,6 +8,25 @@ A Python library for [LanceDB](https://github.com/lancedb/lancedb).
 pip install lancedb
 ```
 
+The core package does not require PyLance. When you need access to the underlying
+Lance dataset or GPU-accelerated indexing, add the `pylance` extra to the
+distribution you already installed.
+
+For the standard distribution:
+
+```bash
+pip install "lancedb[pylance]"
+```
+
+For the pre-Haswell compatibility distribution:
+
+```bash
+pip install "lancedb-compat[pylance]"
+```
+
+Use only the extra matching your installed distribution. Do not install both
+distributions because they share the `lancedb` namespace.
+
 ### Pre-Haswell x86_64 hosts: `lancedb-compat`
 
 The default `lancedb` wheel targets `x86-64-haswell` (AVX2 + FMA + F16C) for full performance on modern hardware. Pre-Haswell hosts — Intel Sandy Bridge / Ivy Bridge / Westmere; AMD Bulldozer / Piledriver / Steamroller — don't have AVX2 and crash with `Illegal instruction` at `import lancedb`.

python/python/lancedb/embeddings/instructor.py

@@ -3,7 +3,6 @@
 
 
 from typing import List
-from urllib.parse import unquote, urlparse
 
 import numpy as np
 
@@ -126,20 +125,9 @@ class InstructorEmbeddingFunction(TextEmbeddingFunction):
 
     @weak_lru(maxsize=1)
     def get_model(self):
-        huggingface_hub = attempt_import_or_raise("huggingface_hub", "huggingface-hub")
-        missing = object()
-        original_cached_download = getattr(huggingface_hub, "cached_download", missing)
-        if original_cached_download is missing:
-            huggingface_hub.cached_download = _cached_download(huggingface_hub)
-
-        try:
-            instructor_embedding = attempt_import_or_raise(
-                "InstructorEmbedding", "InstructorEmbedding"
-            )
-        finally:
-            if original_cached_download is missing:
-                del huggingface_hub.cached_download
-
+        instructor_embedding = attempt_import_or_raise(
+            "InstructorEmbedding", "InstructorEmbedding"
+        )
         torch = attempt_import_or_raise("torch", "torch")
 
         model = instructor_embedding.INSTRUCTOR(self.name)
@@ -152,44 +140,3 @@ class InstructorEmbeddingFunction(TextEmbeddingFunction):
                 model, {torch.nn.Linear}, dtype=torch.qint8
             )
         return model
-
-
-def _cached_download(huggingface_hub):
-    """Provide the legacy download API used by sentence-transformers 2.2.x."""
-
-    def cached_download(
-        *,
-        url,
-        cache_dir=None,
-        force_filename=None,
-        library_name=None,
-        library_version=None,
-        user_agent=None,
-        use_auth_token=None,
-        **_,
-    ):
-        path = urlparse(url).path.lstrip("/")
-        try:
-            repo_id, resolved_path = path.split("/resolve/", maxsplit=1)
-            revision, filename = resolved_path.split("/", maxsplit=1)
-        except ValueError as err:
-            raise ValueError(f"Unsupported Hugging Face Hub URL: {url}") from err
-
-        repo_id = unquote(repo_id)
-        revision = unquote(revision)
-        filename = unquote(filename)
-        # sentence-transformers derives force_filename from this Hub path with
-        # os.path.join. Using the URL path beneath local_dir produces the same
-        # local destination without sending Windows separators to the Hub.
-        return huggingface_hub.hf_hub_download(
-            repo_id=repo_id,
-            filename=filename,
-            revision=revision,
-            local_dir=cache_dir,
-            library_name=library_name,
-            library_version=library_version,
-            user_agent=user_agent,
-            token=use_auth_token,
-        )
-
-    return cached_download

python/python/lancedb/table.py

@@ -117,6 +117,14 @@ _MODEL_BACKED_TOKENIZER_ERRORS = (
     "Failed to initialize default tokenizer",
 )
 
+_PYLANCE_INSTALL_ERROR = (
+    "The lance library is required to use this function. Install the PyLance "
+    "extra for the distribution already installed: "
+    '`pip install "lancedb[pylance]"` for `lancedb`, or '
+    '`pip install "lancedb-compat[pylance]"` for `lancedb-compat`. '
+    "Do not install both distributions because they share the `lancedb` namespace."
+)
+
 
 def _add_unique_note(exception: BaseException, note: str) -> None:
     existing_notes = getattr(exception, "__notes__", ()) or ()
@@ -2249,10 +2257,7 @@ class LanceTable(Table):
         try:
             import lance
         except ImportError:
-            raise ImportError(
-                "The lance library is required to use this function. "
-                "Please install with `pip install pylance`."
-            )
+            raise ImportError(_PYLANCE_INSTALL_ERROR)
 
         branch = self.current_branch()
         version = None if branch is not None else self.version
@@ -4757,10 +4762,7 @@ class AsyncTable:
         try:
             import lance
         except ImportError:
-            raise ImportError(
-                "The lance library is required to use this function. "
-                "Please install with `pip install pylance`."
-            )
+            raise ImportError(_PYLANCE_INSTALL_ERROR)
 
         # lance.dataset() can't open a branch directly, so open the base table
         # and check out the branch ref (a None branch resolves to main).

python/python/tests/test_embeddings.py

@@ -1,11 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright The LanceDB Authors
 
-import ntpath
 import os
 import pickle
-import sys
-from types import ModuleType
 from typing import List, Optional, Union
 from unittest.mock import MagicMock, patch
 
@@ -525,59 +522,6 @@ def test_embedding_function_safe_model_dump(embedding_type):
             )
 
 
-def test_instructor_embedding_supports_huggingface_hub_without_cached_download(
-    tmp_path, monkeypatch
-):
-    from lancedb.embeddings.instructor import InstructorEmbeddingFunction
-
-    hub_download = MagicMock(return_value="/cache/1_Pooling/config.json")
-    huggingface_hub = ModuleType("huggingface_hub")
-    huggingface_hub.hf_hub_download = hub_download
-    torch = ModuleType("torch")
-    monkeypatch.setitem(sys.modules, "huggingface_hub", huggingface_hub)
-    monkeypatch.setitem(sys.modules, "torch", torch)
-    monkeypatch.delitem(sys.modules, "InstructorEmbedding", raising=False)
-    monkeypatch.syspath_prepend(str(tmp_path))
-
-    (tmp_path / "InstructorEmbedding.py").write_text(
-        "from huggingface_hub import cached_download\n\n"
-        "class INSTRUCTOR:\n"
-        "    def __init__(self, name):\n"
-        "        self.name = name\n"
-    )
-
-    embedding = InstructorEmbeddingFunction.create(show_progress_bar=False)
-    instructor_model = embedding.get_model()
-
-    assert instructor_model.name == "hkunlp/instructor-base"
-    assert not hasattr(huggingface_hub, "cached_download")
-
-    instructor_embedding = sys.modules["InstructorEmbedding"]
-    path = instructor_embedding.cached_download(
-        url=(
-            "https://huggingface.co/hkunlp/instructor-base/resolve/abc123/"
-            "1_Pooling/config.json"
-        ),
-        cache_dir="/cache",
-        force_filename=ntpath.join("1_Pooling", "config.json"),
-        library_name="sentence-transformers",
-        library_version="2.2.2",
-        use_auth_token="token",
-    )
-
-    assert path == "/cache/1_Pooling/config.json"
-    hub_download.assert_called_once_with(
-        repo_id="hkunlp/instructor-base",
-        filename="1_Pooling/config.json",
-        revision="abc123",
-        local_dir="/cache",
-        library_name="sentence-transformers",
-        library_version="2.2.2",
-        user_agent=None,
-        token="token",
-    )
-
-
 @patch("time.sleep")
 def test_retry(mock_sleep):
     test_function = MagicMock(side_effect=[Exception] * 9 + ["result"])

python/python/tests/test_import.py

@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright The LanceDB Authors
+
+import subprocess
+import sys
+
+
+def test_import_lancedb_without_pylance():
+    script = """
+import sys
+
+
+class BlockLanceImports:
+    def find_spec(self, fullname, path=None, target=None):
+        if fullname == "lance" or fullname.startswith("lance."):
+            raise ModuleNotFoundError(f"blocked optional dependency: {fullname}")
+        return None
+
+
+sys.meta_path.insert(0, BlockLanceImports())
+import lancedb
+"""
+
+    result = subprocess.run(
+        [sys.executable, "-c", script],
+        capture_output=True,
+        text=True,
+    )
+
+    assert result.returncode == 0, result.stderr

python/python/tests/test_table.py

@@ -1258,6 +1258,24 @@ def test_branch_to_lance_targets_branch(tmp_path):
     assert table.to_lance().count_rows() == 1
 
 
+def _assert_pylance_install_error(error: ImportError):
+    message = str(error)
+    assert 'pip install "lancedb[pylance]"' in message
+    assert 'pip install "lancedb-compat[pylance]"' in message
+    assert "distribution already installed" in message
+    assert "Do not install both distributions" in message
+
+
+def test_to_lance_recommends_pylance_extra(tmp_db):
+    table = tmp_db.create_table("t", [{"i": 1}])
+
+    with patch("builtins.__import__", side_effect=ImportError):
+        with pytest.raises(ImportError) as exc_info:
+            table.to_lance()
+
+    _assert_pylance_install_error(exc_info.value)
+
+
 @pytest.mark.asyncio
 async def test_async_to_lance(tmp_path):
     pytest.importorskip("lance")
@@ -1269,6 +1287,18 @@ async def test_async_to_lance(tmp_path):
     assert dataset.count_rows() == 1
 
 
+@pytest.mark.asyncio
+async def test_async_to_lance_recommends_pylance_extra(tmp_path):
+    db = await lancedb.connect_async(tmp_path)
+    table = await db.create_table("t", [{"i": 1}])
+
+    with patch("builtins.__import__", side_effect=ImportError):
+        with pytest.raises(ImportError) as exc_info:
+            await table.to_lance()
+
+    _assert_pylance_install_error(exc_info.value)
+
+
 @pytest.mark.asyncio
 async def test_async_branch_to_lance_targets_branch(tmp_path):
     pytest.importorskip("lance")