feat(backcompat): accept legacy pool_threads= kwarg on Pinecone.__init__

## Purpose

Legacy callers pass `pool_threads=N` to tune concurrency. The new SDK uses
httpx connection pooling and has no thread-pool concept, so the kwarg needs
to be silently consumed rather than raising TypeError (BCG-020).

## Solution

Added `**kwargs: Any` to `Pinecone.__init__`, popped `pool_threads` before
forwarding. Emits a single `logger.debug(...)` when the kwarg is supplied so
users with `PINECONE_DEBUG` can confirm it was ignored. All other unknown
kwargs still raise `TypeError`. No `DeprecationWarning` per project policy.

Updated the existing `test_pool_threads_raises` test in `test_client.py` to
reflect the new accepted behavior. Added four new tests in `test_pinecone_class.py`:
accepted silently, emits debug log, no DeprecationWarning, unknown kwarg rejected.

Author: jhamon

pinecone/_client.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import logging
 from dataclasses import replace
 from typing import TYPE_CHECKING, Any, cast
 
@@ -46,6 +47,8 @@
     )
     from pinecone.preview import Preview
 
+logger = logging.getLogger(__name__)
+
 
 class Pinecone:
     """Synchronous Pinecone client for control-plane operations.
@@ -100,7 +103,18 @@ def __init__(
         timeout: float = 30.0,
         connection_pool_maxsize: int = 0,
         retry_config: RetryConfig | None = None,
+        **kwargs: Any,
     ) -> None:
+        legacy_pool_threads = kwargs.pop("pool_threads", None)
+        if kwargs:
+            raise TypeError(f"Pinecone() got unexpected keyword arguments: {sorted(kwargs)!r}")
+        if legacy_pool_threads is not None:
+            logger.debug(
+                "Pinecone(pool_threads=%r) is accepted for backcompat but no "
+                "longer used; the new client uses httpx connection pooling. "
+                "Tune connection_pool_maxsize= instead.",
+                legacy_pool_threads,
+            )
         config = PineconeConfig(
             api_key=api_key or "",
             host=host or "",

tests/unit/test_client.py

@@ -165,9 +165,10 @@ def test_openapi_config_raises(self) -> None:
         with pytest.raises(TypeError, match="unexpected keyword argument"):
             Pinecone(api_key="test-key", openapi_config="something")  # type: ignore[call-arg]
 
-    def test_pool_threads_raises(self) -> None:
-        with pytest.raises(TypeError, match="unexpected keyword argument"):
-            Pinecone(api_key="test-key", pool_threads=4)  # type: ignore[call-arg]
+    def test_pool_threads_accepted(self) -> None:
+        # pool_threads= is a backcompat shim (BCG-020); it is silently consumed.
+        pc = Pinecone(api_key="test-key", pool_threads=4)  # type: ignore[call-arg]
+        assert pc is not None
 
     def test_index_api_raises(self) -> None:
         with pytest.raises(TypeError, match="unexpected keyword argument"):

tests/unit/test_pinecone_class.py

@@ -2,8 +2,12 @@
 
 from __future__ import annotations
 
+import logging
+import warnings
 from unittest.mock import MagicMock, patch
 
+import pytest
+
 from pinecone import Pinecone
 from pinecone.inference.models.index_embed import IndexEmbed
 from pinecone.models.enums import CloudProvider
@@ -473,3 +477,32 @@ def test_restore_jobs_cached_on_second_access(self) -> None:
         pc = Pinecone(api_key="test-key")
         first_access = pc.restore_jobs
         assert pc.restore_jobs is first_access
+
+
+# ---------------------------------------------------------------------------
+# pool_threads= backcompat shim (BCG-020)
+# ---------------------------------------------------------------------------
+
+
+class TestPoolThreadsBackcompat:
+    def test_pool_threads_kwarg_accepted_silently(self) -> None:
+        pc = Pinecone(api_key="x", pool_threads=4)
+        assert pc is not None
+
+    def test_pool_threads_kwarg_emits_debug_log(self, caplog: pytest.LogCaptureFixture) -> None:
+        with caplog.at_level(logging.DEBUG, logger="pinecone._client"):
+            Pinecone(api_key="x", pool_threads=4)
+        assert any(
+            "pool_threads" in r.message and "connection_pool_maxsize" in r.message
+            for r in caplog.records
+        )
+
+    def test_pool_threads_kwarg_does_not_warn(self) -> None:
+        with warnings.catch_warnings(record=True) as record:
+            warnings.simplefilter("always")
+            Pinecone(api_key="x", pool_threads=4)
+        assert len(record) == 0
+
+    def test_unknown_kwarg_still_rejected(self) -> None:
+        with pytest.raises(TypeError, match="unexpected keyword arguments"):
+            Pinecone(api_key="x", bogus_kwarg=True)