This method is dead code - not documented, not tested. As far as we know, it
can be horribly broken.

to reject invalid UTF-16 surrogate.

code points bigger than U+10ffff

response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.

response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.

response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.

This removes the dependency on bisect and it bring the pure Python code
in-sync with the C code.

Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.

Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.

Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.

Keep references for oldkey and oldvalue so they can't
trigger a __del__ method to reenter our thread.

Move the cache[key]=link step to the end, after the link
data is in a consistent state.

Under exotic circumstances, the cache[key]=link step could
trigger reentrancy (i.e. the key would have to have a hash
exactly equal to that for another key in the cache and the
key would need a __eq__ method that makes a reentrant call
our cached function).