Re: [RFA v2 00/13] various frame filter fixes and cleanups

[Phil Muldoon <pmuldoon at redhat dot com>]

On 14/08/17 14:20, Pedro Alves wrote:
> On 08/14/2017 04:40 AM, Tom Tromey wrote:
> 
>>> So "bt elide" means "elide the elided frames", not "show me the
>>> elided frames too".  It's fine with me, though I mildly wonder whether
>>> users will be confused by the "double negative".
>>
>> "Elide" means "drop", so really "bt elide" should mean "drop whatever
>> frames are droppable". Having "bt elide" mean "show the dropped
>> frames" would be confusing.  But maybe another word would be better
>> here, I don't know.
> 
> Maybe "bt no-elided", to go with "bt no-filters".
> 
> Because "elided frames" are a preexisting concept, and "elide" is
> actually referring to that concept.

I suggest hidden or show-hidden or something like that.

> 
>  @item backtrace no-elided
>  A Python frame filter might decide to ``elide'' some frames.  Normally
>  such elided frames are still printed, but they are indented relative
>  to the filtered frames that cause them to be elided.  The @code{no-elided}
>  option causes elided frames to not be printed at all.
> 
> Or alternatively, to make gdb not print elided frames by default and
> add a "bt elided" switch to print them:
> 
>  @item backtrace elided
>  A Python frame filter might decide to ``elide'' some frames.  Normally
>  such elided frames are not printed.  The @code{elided} option causes
>  elided frames to be printed, indented relative to the filtered frames
>  that cause them to be elided.  

I'd prefer a "hidden" attribute to the frame decorators (or a callback
API like the rest of the functions). Returns True or False. GDB would
honour this and print/not print the frame according to the value
returned. This is better, to me, than a global override printing/not
printing all elided frames. The bt command should still have a global
override (IE, elide, or hidden, or show-hidden, or whatever) as
discussed in the patch, and that would allow the user final and manual
control of what is printed or not. I prefer frame decorators to be
able to decide what should, or should not, be printed as the default
as it's the presentation layer.

What do you think?

Cheers

Phil