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

0.2.8 stored self.api_key on the client and _headers() re-read it per
request, so reading client.api_key and reassigning it after construction
both worked. The refactor handed the key to the internal backends and never
set it on PageIndexClient: reads raised AttributeError and reassignment
silently kept requests on the old key. Same shape as the BASE_URL snapshot
fixed in dea211b — apply the same callable-indirection pattern to api_key
on both CloudBackend and LegacyCloudAPI (which also stops CloudBackend
snapshotting its headers dict at construction).

pageindex/backend/cloud.py

@@ -30,17 +30,24 @@ def _as_int(value):
 
 
 class CloudBackend:
-    def __init__(self, api_key: str, base_url: str | Callable[[], str] | None = None):
+    def __init__(self, api_key: str | Callable[[], 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 api_key(self) -> str:
+        return self._api_key() if callable(self._api_key) else self._api_key
+
     @property
     def base_url(self) -> str:
         return self._base_url() if callable(self._base_url) else self._base_url
 
+    def _headers(self) -> dict[str, str]:
+        return {"api_key": self.api_key}
+
     # ── HTTP helpers ──────────────────────────────────────────────────────
 
     # Folder API statuses meaning "folders are not available on this account"
@@ -77,7 +84,7 @@ class CloudBackend:
                     if hasattr(fobj, "seek"):
                         fobj.seek(0)
             try:
-                resp = requests.request(method, url, headers=self._headers, **kwargs)
+                resp = requests.request(method, url, headers=self._headers(), **kwargs)
                 if resp.status_code in (429, 500, 502, 503):
                     last_status = resp.status_code
                     if attempt == retries - 1:
@@ -452,7 +459,7 @@ class CloudBackend:
         )
         if not doc_id:
             raise ValueError("collection has no documents to query")
-        headers = self._headers
+        headers = self._headers()
         base_url = self.base_url
         # Queue carries QueryEvent, an Exception to re-raise, or None (end).
         queue: asyncio.Queue[QueryEvent | Exception | None] = asyncio.Queue()

pageindex/client.py

@@ -74,11 +74,13 @@ class PageIndexClient:
     def _init_cloud(self, api_key: str):
         from .backend.cloud import CloudBackend
         from .cloud_api import LegacyCloudAPI
-        # Callable: re-read per request so post-construction BASE_URL
+        # Callables: re-read per request so post-construction BASE_URL /
-        # reassignment (a 0.2.x pattern) still applies.
+        # api_key reassignment (0.2.x patterns) still applies.
+        self.api_key = api_key
         base_url = lambda: self.BASE_URL
-        self._backend = CloudBackend(api_key=api_key, base_url=base_url)
+        api_key_ref = lambda: self.api_key
-        self._legacy_cloud_api = LegacyCloudAPI(api_key=api_key, base_url=base_url)
+        self._backend = CloudBackend(api_key=api_key_ref, base_url=base_url)
+        self._legacy_cloud_api = LegacyCloudAPI(api_key=api_key_ref, 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

@@ -19,10 +19,19 @@ class LegacyCloudAPI:
 
     BASE_URL = API_BASE
 
-    def __init__(self, api_key: str, base_url: str | Callable[[], str] | None = None):
+    def __init__(self, api_key: str | Callable[[], str],
-        self.api_key = api_key
+                 base_url: str | Callable[[], str] | None = None):
+        self._api_key = api_key
         self._base_url = base_url or self.BASE_URL
 
+    @property
+    def api_key(self) -> str:
+        return self._api_key() if callable(self._api_key) else self._api_key
+
+    @api_key.setter
+    def api_key(self, value: str | Callable[[], str]) -> None:
+        self._api_key = value
+
     @property
     def base_url(self) -> str:
         return self._base_url() if callable(self._base_url) else self._base_url