Howard Chu writes:

The tooLate reply is correct; back-null doesn't ever check for cancel/abandon therefore the operation is *not* successfully canceled. Likewise, back-bdb/hdb only checks in Delete if there is a transaction retry.

No difference if I use back-ldif, which does check for abandon.

The lack of reply from the original op - that's a simple oversight. send_ldap_ber() checks for op->o_abandon and returns silently if it's set. I guess we need to also check for o_cancel to let it proceed.

The operation does not reach send_ldap_ber(). To verify, I temporarily inserted assert(!op->o_abandon) just before send_ldap_ber()'s o_abandon test. send_ldap_response() notices both o_abandon and SLAPD_ABANDON, and skips to the cleanup code in either case.

Also, backend operations that do return SLAPD_ABANDON - at least Search in backglue and BDB - may do so without calling send_ldap_response() at all. Pierangelo made partial fixes in ITS#4645. See also ITS#6059, which I may have misunderstood somewhat. (Sorry, Rein.)

Maybe o_abandon should only mean that: - (a) the backend has been asked to abandon the operation, - (b) slapd must check and react to o_cancel, - (c) if not o_cancel, send_ldap_ber() need not send.