Re: [PATCH 0/2] info breakpoints improvements

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 23 May 2022 18:06:22 +0100
> Cc: gdb-patches@sourceware.org
> From: Pedro Alves <pedro@palves.net>
> 
> >>  (top-gdb) info breakpoints
> >>  Num     Type           Disp Enb Address            What
> >>  1       breakpoint     keep y                      internal_error
> >>   1.1                        y   0x00000000005755a5 in internal_error(char const*, int, char const*, ...) at src/gdb/common/errors.c:54
> >>  2       breakpoint     keep y                      -qualified internal_error
> >>   2.1                        y   0x00000000005755a5 in internal_error(char const*, int, char const*, ...) at src/gdb/common/errors.c:54
> >>  3       breakpoint     keep y                      errors.c:54
> >>   3.1                        y   0x00000000005755a5 in internal_error(char const*, int, char const*, ...) at src/gdb/common/errors.c:54
> >>   3.2                        y   0x00007ffff6d50410 in PyErr_SetObject at /usr/src/debug/python2-2.7.15-4.fc27.x86_64/Python/errors.c:54
> >>  4       breakpoint     keep y                      gdb.c:27
> >>   4.1                        y   0x000055555564107b in main(int, char**) at src/gdb/gdb.c:28
> >>  (top-gdb)
> > 
> > I must confess that the new display is much more cluttered, and
> > includes redundant information, so it's harder to read.  It also makes
> > the important stuff harder to find.  Why exactly is this deemed as
> > improvement, and in particular, why would we want this behavior as the
> > default?  (I won't mind to have this as opt-in behavior, if someone
> > finds this useful in some situations.)
> 
> None of the information is actually redundant.  The "Enb" column shows
> a different "y", as you can disable a whole breakpoint, or its locations
> independently.

In the "usual" case, such as the one below:

> >>  4       breakpoint     keep y                      gdb.c:127
> >>   4.1                        y   0x000055555564107b in main(int, char**) at src/gdb/gdb.c:127

one of the two "y"s is redundant, as well as one of the two
"gdb.c:127"s.  And in this case:

>>  1       breakpoint     keep y                      internal_error
>>   1.1                        y   0x00000000005755a5 in internal_error(char const*, int, char const*, ...) at src/gdb/common/errors.c:54

the "internal_error" part of the "header row" is also redundant.

> The "What" column is showing different things for the breakpoint
> and its locations.

Different, but in many cases quite similar, with many common parts.

> >>  Num     Type           Disp Enb What
> >>  1       breakpoint     keep y   internal_error
> >>  2       breakpoint     keep y   -qualified internal_error
> >>  3       breakpoint     keep y   errors.c:54
> > 
> > If we want a concise display that only shows the important parts, I'd
> > lose the "Disp" column.
> 
> I'm not sure how you're determining "important".  That'd make it impossible to
> distinguish a "break" from a "tbreak".  I'm only after hiding the breakpoint locations.

IME, the "tbreak" vs "break" difference is much less important than
the rest.

> So, a more concise display may be interesting, but I'd like to think of it as
> a separate feature.

It's okay to disagree about user perspectives on what a "concise"
display should and should not have.  I thought that providing the
perspective of one (heavy) user of GDB on this will help make the
discussion more objective and balanced.  Apologies if that is not
useful.