fix: resolve BASE_URL at request time to restore 0.2.x override semantics

PageIndexClient snapshotted BASE_URL into CloudBackend and LegacyCloudAPI
at construction, so reassigning client.BASE_URL afterwards was silently
ignored and requests kept going to the default endpoint. Pass a callable
resolved per request instead, so instance- and class-level reassignment
after construction work again alongside the pre-construction override.

Claude-Session: https://claude.ai/code/session_014B4HZkjdSiZXDmJtH5Jexn

pageindex/backend/cloud.py

@@ -11,7 +11,7 @@ import re
 import time
 import urllib.parse
 import requests
-from typing import AsyncIterator
+from typing import AsyncIterator, Callable
 
 from ..cloud_api import API_BASE  # single source of truth for the cloud base URL
 from ..errors import (AUTH_HINT, CloudAPIError, CollectionNotFoundError,
@@ -31,13 +31,19 @@ def _as_int(value):
 
 
 class CloudBackend:
-    def __init__(self, api_key: str, base_url: str | None = None):
+    def __init__(self, api_key: str, base_url: str | Callable[[], str] | None = None):
         self._api_key = api_key
         self._base_url = base_url or API_BASE
         self._headers = {"api_key": api_key}
         self._folder_id_cache: dict[str, str | None] = {}
         self._folder_warning_shown = False
 
+    @property
+    def base_url(self) -> str:
+        # A callable is resolved per request so reassigning client.BASE_URL
+        # after construction takes effect, matching 0.2.x call-time semantics.
+        return self._base_url() if callable(self._base_url) else self._base_url
+
     # ── HTTP helpers ──────────────────────────────────────────────────────
 
     # Folder API statuses meaning "folders are not available on this account"
@@ -61,7 +67,7 @@ class CloudBackend:
         """HTTP helper. ``retries`` caps total attempts — pass 1 for
         non-idempotent, expensive calls (e.g. chat completions) where a
         retry would redo the full server-side work."""
-        url = f"{self._base_url}{path}"
+        url = f"{self.base_url}{path}"
         kwargs.setdefault("timeout", 30)
         last_status: int | None = None
         for attempt in range(retries):
@@ -430,7 +436,7 @@ class CloudBackend:
         if not doc_id:
             raise ValueError("collection has no documents to query")
         headers = self._headers
-        base_url = self._base_url
+        base_url = self.base_url
         # Queue carries QueryEvent, an Exception to re-raise, or None (end).
         queue: asyncio.Queue[QueryEvent | Exception | None] = asyncio.Queue()
         loop = asyncio.get_running_loop()

pageindex/client.py

@@ -74,8 +74,11 @@ class PageIndexClient:
     def _init_cloud(self, api_key: str):
         from .backend.cloud import CloudBackend
         from .cloud_api import LegacyCloudAPI
-        self._backend = CloudBackend(api_key=api_key, base_url=self.BASE_URL)
-        self._legacy_cloud_api = LegacyCloudAPI(api_key=api_key, base_url=self.BASE_URL)
+        # Pass a callable so BASE_URL is re-read on every request — 0.2.x
+        # allowed reassigning client.BASE_URL after construction.
+        base_url = lambda: self.BASE_URL
+        self._backend = CloudBackend(api_key=api_key, base_url=base_url)
+        self._legacy_cloud_api = LegacyCloudAPI(api_key=api_key, base_url=base_url)
 
     def _init_local(self, model: str = None, retrieve_model: str = None,
                     storage_path: str = None, storage=None,

pageindex/cloud_api.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import json
 import urllib.parse
-from typing import Any, Iterator
+from typing import Any, Callable, Iterator
 
 import requests
 
@@ -19,9 +19,19 @@ class LegacyCloudAPI:
 
     BASE_URL = API_BASE
 
-    def __init__(self, api_key: str, base_url: str | None = None):
+    def __init__(self, api_key: str, base_url: str | Callable[[], str] | None = None):
         self.api_key = api_key
-        self.base_url = base_url or self.BASE_URL
+        self._base_url = base_url or self.BASE_URL
+
+    @property
+    def base_url(self) -> str:
+        # A callable is resolved per request so reassigning client.BASE_URL
+        # after construction takes effect, matching 0.2.x call-time semantics.
+        return self._base_url() if callable(self._base_url) else self._base_url
+
+    @base_url.setter
+    def base_url(self, value: str | Callable[[], str]) -> None:
+        self._base_url = value
 
     @staticmethod
     def _enc(value: str) -> str:

tests/test_cloud_backend.py

@@ -137,7 +137,7 @@ def test_client_base_url_override_reaches_both_backends():
         BASE_URL = "https://staging.example.com"
 
     client = StagingClient(api_key="pi-test")
-    assert client._backend._base_url == "https://staging.example.com"
+    assert client._backend.base_url == "https://staging.example.com"
     assert client._legacy_cloud_api.base_url == "https://staging.example.com"
 
 

tests/test_legacy_sdk_contract.py

@@ -84,6 +84,23 @@ def test_legacy_base_url_can_be_overridden_from_client(monkeypatch):
     assert calls[0]["headers"] == {"api_key": "pi-test"}
 
 
+def test_legacy_base_url_reassignment_after_construction(monkeypatch):
+    calls = []
+
+    def fake_request(method, url, headers=None, **kwargs):
+        calls.append({"method": method, "url": url})
+        return FakeResponse(payload={"id": "doc-1"})
+
+    monkeypatch.setattr("pageindex.cloud_api.requests.request", fake_request)
+
+    client = PageIndexClient("pi-test")
+    client.BASE_URL = "https://staging.pageindex.test"
+    client.get_document("doc-1")
+
+    assert calls[0]["url"] == "https://staging.pageindex.test/doc/doc-1/metadata/"
+    assert client._backend.base_url == "https://staging.pageindex.test"
+
+
 def test_submit_document_uses_legacy_endpoint(monkeypatch, tmp_path):
     calls = []