From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
cc: pgsql-hackers@lists.postgresql.org, steven.winfield@cantabcapital.com
Subject: Re: BUG #16059: Tab-completion of filenames in COPY commands removes
 required quotes
In-reply-to: <4158.1576129790@sss.pgh.pa.us>
References: <20191211015552.GA6301@alvherre.pgsql>
 <17796.1576082603@sss.pgh.pa.us> <4158.1576129790@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Thu, 12 Dec 2019 00:49:50 -0500"
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Content-ID: <23607.1576248145.1@sss.pgh.pa.us>
Date: Fri, 13 Dec 2019 09:42:25 -0500
Message-ID: <23608.1576248145@sss.pgh.pa.us>
Precedence: bulk

I wrote:
>> Alvaro Herrera <alvherre@2ndquadrant.com> writes:
>>> I don't quite understand why a readline library that doesn't have
>>> rl_filename_completion_function is known to have a
>>> filename_completion_function, ie. this bit 

>>> #ifdef HAVE_RL_FILENAME_COMPLETION_FUNCTION
>>> #define filename_completion_function rl_filename_completion_function
>>> #else
>>> /* decl missing in some header files, but function exists anyway */
>>> extern char *filename_completion_function();
>>> #endif

>> I think the point is that before rl_filename_completion_function the
>> function existed but was just called filename_completion_function.
>> It's possible that that's obsolete --- I've not really checked.

Looking closer at this, the "extern" could be got rid of, I think.
prairiedog's readline header does have that extern, so it's hard to
believe anybody is still using libedit versions that don't declare it.

A possible further change is to switch the code over to calling
"rl_filename_completion_function", and then invert the sense of
this logic, like

/*
 * Ancient versions of libedit provide filename_completion_function()
 * instead of rl_filename_completion_function().
 */
#ifndef HAVE_RL_FILENAME_COMPLETION_FUNCTION
#define rl_filename_completion_function filename_completion_function
#endif

This would make it easier to compare our code to the readline
documentation, so maybe it's helpful ... or maybe it's just
churn.  Thoughts?

			regards, tom lane