R devel - Apr 2018 - debugonce() functions are not considered as debugged

debugonce() sets a different flag (RSTEP), and this is not queried by
isdebugged(), and it is also not unset by undebug().

Is this expected? If yes, is there a way to query and unset the RSTEP flag
from R code?

? f <- function() { }
? debugonce(f)
? isdebugged(f)
[1] FALSE

? undebug(f)
Warning message:
In undebug(f) : argument is not being debugged

? f()
debugging in: f()
debug at #1: {
}
Browse[2]>

Gabor,

Others can speak to the origins of this more directly, but from what I
recall this has been true at least since I was working in this space on the
debugcall stuff a couple years ago. I imagine the reasoning  is what you
would expect: a single bit of course can't tell R both that a function is
debugged AND that it should undebug after the first call.  I don't know of
any R-facing way to check for debugonce status, though its possible I
missed it

That said, it would be possible to alter how the two bits are used so that
debugonce sets both of them, and debug (not once) only sets one, rather
them being treated as mutually exclusive. This would alter the behavior so
that debugonce'ed functions that haven't been called yet are considered
debugged, e.g., by isdebugged.

This would not, strictly speaking, be backwards compatible, but by the very
nature of what debugging means, it would not break any existing script
code. It could, and likely would, effect code implementing GUIs, however.

R-core - is this a patch that you are interested in and would consider
incorporating? If so I can volunteer to work on it.

Best,
~G

On Sat, Apr 28, 2018 at 4:57 AM, G?bor Cs?rdi <csardi.gabor at gmail.com>
wrote:
> debugonce() sets a different flag (RSTEP), and this is not queried by
> isdebugged(), and it is also not unset by undebug().
>
> Is this expected? If yes, is there a way to query and unset the RSTEP flag
> from R code?
>
> ? f <- function() { }
> ? debugonce(f)
> ? isdebugged(f)
> [1] FALSE
>
> ? undebug(f)
> Warning message:
> In undebug(f) : argument is not being debugged
>
> ? f()
> debugging in: f()
> debug at #1: {
> }
> Browse[2]>
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

-- 
Gabriel Becker, Ph.D
Scientist
Bioinformatics and Computational Biology
Genentech Research

	[[alternative HTML version deleted]]

debug(fun) marks "fun" for debugging, it makes sure that whenever
"fun"
is called, the debugger is entered
undebug(fun) removes this mark; it won't stop any current debugging of 
that function
isdebugged(fun) tells whether this mark is set or not; it does not tell 
whether "fun" is currently running in a debugger/browser

debugonce(func) adds a different mark to the function, one that makes 
sure the first time "fun" is called, the debugger is entered; this is 
the same as when entering that function via "s" while debugging its 
caller. There is no way to query or unset this mark.

Do you have a good use case when it would be useful to query/unset the 
mark for debugonce?

Best,
Tomas

On 04/28/2018 01:57 PM, G?bor Cs?rdi wrote:
> debugonce() sets a different flag (RSTEP), and this is not queried by
> isdebugged(), and it is also not unset by undebug().
>
> Is this expected? If yes, is there a way to query and unset the RSTEP flag
> from R code?
>
> ? f <- function() { }
> ? debugonce(f)
> ? isdebugged(f)
> [1] FALSE
>
> ? undebug(f)
> Warning message:
> In undebug(f) : argument is not being debugged
>
> ? f()
> debugging in: f()
> debug at #1: {
> }
> Browse[2]>
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

On Mon, May 21, 2018 at 5:01 PM Tomas Kalibera <tomas.kalibera at
gmail.com>
wrote:
[...]
> Do you have a good use case when it would be useful to query/unset the
> mark for debugonce?
Well, I suppose the same use cases when it is useful to query/unset the
other debug
mark.

To be more specific, in debug helpers for a tool that works with callbacks
from a central event loop, it is nice to be able to tell which callbacks are
"debugged" currently, either via `debug()` or  `debugonce()`.

Gabor
> Best,
> Tomas
> On 04/28/2018 01:57 PM, G?bor Cs?rdi wrote:
> > debugonce() sets a different flag (RSTEP), and this is not queried by
> > isdebugged(), and it is also not unset by undebug().
> >
> > Is this expected? If yes, is there a way to query and unset the RSTEP
flag
> > from R code?
> >
> > ? f <- function() { }
> > ? debugonce(f)
> > ? isdebugged(f)
> > [1] FALSE
> >
> > ? undebug(f)
> > Warning message:
> > In undebug(f) : argument is not being debugged
> >
> > ? f()
> > debugging in: f()
> > debug at #1: {
> > }
> > Browse[2]>
> >
> > ______________________________________________
> > R-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel