back-bdb returns duplicate search results (ITS#2044)

[hyc@OpenLDAP.org]

Full_Name: Howard Chu
Version: 2.1.x
OS: 
URL: 
Submission from: (NULL) (24.130.38.213)
Submitted by: hyc


This problem was originally reported by Ian Logan @NMSU.Edu on the -software
list.

The problem occurs in search filters with unions, and causes some entries to be
returned multiple times.

This is due to a bug in bdb_idl_union(a, b) that is triggered when the range of
b is contained within the range of a. (e.g., a = {1,3,5} and b = {4} will result
in {1,3,4,1}.)

This will be fixed in CVS HEAD momentarily.