[utils] OnDemandPagedList: Do not download pages after error

yt_dlp/utils.py

@@ -2799,13 +2799,14 @@ def __len__(self):
     def __init__(self, pagefunc, pagesize, use_cache=True):
         self._pagefunc = pagefunc
         self._pagesize = pagesize
+        self._pagecount = float('inf')
         self._use_cache = use_cache
         self._cache = {}
 
     def getpage(self, pagenum):
         page_results = self._cache.get(pagenum)
         if page_results is None:
-            page_results = list(self._pagefunc(pagenum))
+            page_results = [] if pagenum > self._pagecount else list(self._pagefunc(pagenum))
         if self._use_cache:
             self._cache[pagenum] = page_results
         return page_results
@@ -2817,7 +2818,7 @@ def _getslice(self, start, end):
         raise NotImplementedError('This method must be implemented by subclasses')
 
     def __getitem__(self, idx):
-        # NOTE: cache must be enabled if this is used
+        assert self._use_cache, 'Indexing PagedList requires cache'
         if not isinstance(idx, int) or idx < 0:
             raise TypeError('indices must be non-negative integers')
         entries = self.getslice(idx, idx + 1)
@@ -2843,7 +2844,11 @@ def _getslice(self, start, end):
                 if (end is not None and firstid <= end <= nextfirstid)
                 else None)
 
+            try:
                 page_results = self.getpage(pagenum)
+            except Exception:
+                self._pagecount = pagenum - 1
+                raise
             if startv != 0 or endv is not None:
                 page_results = page_results[startv:endv]
             yield from page_results
@@ -2863,8 +2868,8 @@ def _getslice(self, start, end):
 
 class InAdvancePagedList(PagedList):
     def __init__(self, pagefunc, pagecount, pagesize):
-        self._pagecount = pagecount
         PagedList.__init__(self, pagefunc, pagesize, True)
+        self._pagecount = pagecount
 
     def _getslice(self, start, end):
         start_page = start // self._pagesize