.

wcfs/wcfs_test.py

@@ -900,6 +900,14 @@ def watch(twlink, zf, at, pinok=None): # -> tWatch
             assert at  <  blkRevAt(blk, headOfAccess[blk])
 
         # blk ∈ pin_prev,   blk ∉ pin       -> unpin to head
+        #
+        # FIXME
+        #
+        #     δ(accessed)     δ(not-accessed)
+        #   ----x----------------o-----------------]-----
+        #      at_prev          at               head
+        #
+        # -> must pin to at? (not unpin @head)
         elif blk in pin_prev and blk not in pin:
             # blk ∈ pin_prev -> blk was already accessed with rev > at_prev
             assert blk in headOfAccess