Re: incompatible changes of PQsetdbLogin()

Tatsuo Ishii <t-ishii@sra.co.jp> writes:
> It seems some incompatible changes have been made between 7.0 and
> current. In 7.0, if a parameter is NULL OR a null string (""), then
> the value from an environment variable is applied. However in current
> ONLY NULL is considered. Is there any reason for this?

Peter E. did that recently, after discussion that concluded it was a
good idea --- otherwise there is no way to override an environment
variable with an empty string.  Do you have an example where it's
a bad idea?
        regards, tom lane