Fixed #28679 -- Fixed urlencode()'s handling of bytes.

Regression in fee42fd99e.

Thanks Claude Paroz, Jon Dufresne, and Tim Graham for the guidance.

django/utils/http.py

@@ -88,11 +88,24 @@ def urlencode(query, doseq=False):
         query = query.lists()
     elif hasattr(query, 'items'):
         query = query.items()
-    return original_urlencode(
-        [(k, [str(i) for i in v] if isinstance(v, (list, tuple)) else str(v))
-         for k, v in query],
-        doseq
-    )
+    query_params = []
+    for key, value in query:
+        if isinstance(value, (str, bytes)):
+            query_val = value
+        else:
+            try:
+                iter(value)
+            except TypeError:
+                query_val = value
+            else:
+                # Consume generators and iterators, even when doseq=True, to
+                # work around https://bugs.python.org/issue31706.
+                query_val = [
+                    item if isinstance(item, bytes) else str(item)
+                    for item in value
+                ]
+        query_params.append((key, query_val))
+    return original_urlencode(query_params, doseq)
 
 
 def cookie_date(epoch_seconds=None):