Re: wrapping in extended mode doesn't work well with default pager - Mailing list pgsql-hackers

Emre Hasegeli <emre@hasegeli.com> writes:
> Pavel Stehule <pavel.stehule@gmail.com>:
>> I am checking feature
>> http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=6513633b94173fc1d9e2b213c43f9422ddbf5faa
>> 
>> It works perfect with pager "less", but it works badly with default "more"

> I do not think so. It looks broken with or without any pager when
> border != 2. Your less configuration might be hiding the problem from you.

This seems broken in several ways.  I tried this test case:

regression=# \x \pset format wrapped
Expanded display (expanded) is on.
Output format (format) is wrapped.
regression=# select * from pg_proc where prolang!=12;

In 9.3, the output looks like this:

-[ RECORD 1 ]---+---------------------------------------------------------------
--------------------------------------------------------------------------------
------------------------------------
proname         | to_timestamp
pronamespace    | 11
proowner        | 10
prolang         | 14
procost         | 1
prorows         | 0
provariadic     | 0
protransform    | -
...

In HEAD, I see:

-[ RECORD 1 ]---+---------------------------------------------------------------proname         | to_timestamp
                                       pronamespace    | 11
proowner       | 10                                                            prolang         | 14
                                      procost         | 1
prorows        | 0                                                             provariadic     | 0
                                      protransform    | -                                                             
 
After "\pset columns 77" it looks a little better:

-[ RECORD 1 ]---+------------------------------------------------------------proname         | to_timestamp
                                  pronamespace    | 11
proowner       | 10                                                          prolang         | 14
                                  procost         | 1                                                           prorows
       | 0                                                           provariadic     | 0
                          protransform    | -                                                           proisagg
|f                                                           proiswindow     | f
                  
 

but where did those leading spaces come from?  The header line is
definitely not on board with that, and I think those spaces are
contributing to the lines being too long for the window.  I think
possibly the code is also adding a space that shouldn't be there
at the end of the lines, because it prints lines that wrap around
if I \pset columns to either 79 or 80 in an 80-column window, so
the accounting is off by 2 someplace.

Also, this code looks quite broken:
        width = dwidth + swidth + hwidth;        if ((output_columns > 0) && (width > output_columns))        {
  dwidth = output_columns - hwidth - swidth;            width = output_columns;        }
 

What happens if output_columns is less than hwidth + swidth?  The code
goes crazy is what happens, because all of these are unsigned ints and so
wraparound leads to setting dwidth to something approaching 4 billion.
Try the same example after "\pset columns 10".  I don't necessarily expect
it to produce beautiful output, but I do expect it to not lock up.
        regards, tom lane