Bug in libpq implentation and omission in documentation?

Hello PG hackers. Yesterday I began diagnosing a peculiar bug in some
production code that has been happily running for months. I finally got
to the bottom of it despite the rather misleading error message. Anyway,
within a section of code we are making a DELETE call to the database via
the libpq call PQexecParams(). It failed with this message:

'ERROR: bind message has 32015 parameter formats but 1 parameters'

This was just plain wrong. In fact, the # of parameters was more like
80,000. The area of code is quite clear. Despite this being a
particularly large number of parameters (as you can imagine this query
is built dynamically based on arbitrarily sized input) the data type for
nParams for is a plain old 4-byte int. Upon further and deeper
inspection I find that this 4 byte int is truncated to two bytes just
before going down the wire.

There is no mention of any restriction in the 9.1.4 documentation:

http://www.postgresql.org/docs/9.1/static/libpq-exec.html

And the interface quite clearly accepts a 4 byte int however, the PQsendQueryGuts()
function on line 1240 of src/interfaces/libpq/fq-exec.c just blatantly truncates the
integer - it's calls pqPutInt() for nParams with a literal 2 rather than 4. It does this
several times, in fact.

Unless I'm barking mad, surely this should either

a) Be fixed and send 4 with nParams for pqPutInt() rather than 2
b) Documented (and the type changed) as only being a 2 byte int
and therefore having a restriction on the number of parameters
permitted in PQexecParams().

Could someone either verify or correct me before I submit an official bug report!?

Regards,

Jim Vanns

--
Jim Vanns
Systems Programmer
Framestore