BUG #14287: psql_history gets wiped out

The following bug has been logged on the website:

Bug reference: 14287
Logged by: Rick Otten
Email address: rotten(at)windfish(dot)net
PostgreSQL version: 9.5.3
Operating system: Ubuntu 14.04
Description:

I believe this behavior is new to the 9.5.3 psql client. It has been
bugging me ever since we patched to that release.

The psql_history file works fine unless you close your window without
exiting the psql shell. If you just drop your window (and corresponding ssh
session), the entire psql_history file will get wiped out. (file size 0)

This took me quite a while to figure out. My history would be there
sometimes when I came back, and other times it would be wiped out. At first
I thought I had a hacker trying to hide their tracks. After some research I
concluded that was not the case.

It was a colleague whom I observed closing their putty window without first
exiting the psql shell this morning that finally revealed how it was
happening.

It is reproducible in our environment.