[Rd] sprintf causes a segfault (PR#13613)

2009-03-20 Thread waku 
Full_Name: Wacek Kusnierczyk
Version: 2.8.0 and 2.10.0 r48163
OS: Ubuntu 8.04 Linux 32bit
Submission from: (NULL) (129.241.198.172)


the following code illustrates a problem with sprintf which consistently causes
a segfault when applied to certain type of arguments.  it also shows
inconsistent consequences of the segfault:

   (e = tryCatch(stop(), error=identity))
   # e is an error object

   sprintf('%d', e)
   # error in sprintf(%d, e) : unsupported type

   sprintf('%f', e)
   # error in sprintf(%f, e) : (list) object cannot be coerced to type
'double'

   sprintf('%s', e)
   # segfault reported, with a choice of options for how to exit the session

it is possible not to leave the session, by simply typing ^c (ctrl-c).  (which
should probably be prohibited.)  if one stays in the session, then trying to
evaluate sprintf('%s', e) will cause a segfault with immediate crash (r is
silently closed), but not necessarily if some other code is executed first.  in
the latter case, there may be no segfault, but an error message might be printed
instead:

   e = tryCatch(stop(), error=identity)
   sprintf('%s', e)
   # segfault, choice of options
   # ^c, stay in the session
   e = tryCatch(stop(), error=identity)
   sprintf('%s', e)
   # segfault, immediate exit
 
   e = tryCatch(stop(), error=identity)
   sprintf('%s', e)
   # segfault, choice of options
   # ^c, stay in the session
   e = tryCatch(stop(), error=identity)
   x = 1 # possibly, whatever code would do
   sprintf('%s', e)
   # [1] Error in doTryCatch(return(expr), name, parentenv, handler): \n
   # [2] Error in doTryCatch(return(expr), name, parentenv, handler): \n
   sprintf('%s', e)
   # segfault, immediate exit

in the second code snippet above, on some executions the error message was
printed. on others a segfault caused immediate exit.  (the pattern seems to
differ between 2.8.0 and 2.10.0-devel.)

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Re: [Rd] sprintf causes a segfault (PR#13613)

2009-03-20 Thread Wacek Kusnierczyk 
strangely enough, the way r handles the same sequence of expressions on
different occasions varies:

# fresh session 1
e = simpleError('foo')
sprintf('%s', e)
# segfault: address 0x202, cause memory not mapped
# ^c
sprintf('%s', e)
# error in sprintf(%s, e) : 'getEncChar' must be called on a CHARSXP
  
# fresh session 2
e = simpleError('foo')
sprintf('%s', e)
# segfault: address (nil), cause memory not mapped
# ^c
sprintf('%s', e)
# segfault, exit

note the difference in the address and how this relates to the outcome
of the second execution of sprintf('%s', e)

vQ


waclaw.marcin.kusnierc...@idi.ntnu.no wrote:
 the following code illustrates a problem with sprintf which consistently 
 causes
 a segfault when applied to certain type of arguments.  it also shows
 inconsistent consequences of the segfault:

(e = tryCatch(stop(), error=identity))
# e is an error object

sprintf('%d', e)
# error in sprintf(%d, e) : unsupported type

sprintf('%f', e)
# error in sprintf(%f, e) : (list) object cannot be coerced to type
 'double'

sprintf('%s', e)
# segfault reported, with a choice of options for how to exit the session

 it is possible not to leave the session, by simply typing ^c (ctrl-c).  (which
 should probably be prohibited.)  if one stays in the session, then trying to
 evaluate sprintf('%s', e) will cause a segfault with immediate crash (r is
 silently closed), but not necessarily if some other code is executed first.  
 in
 the latter case, there may be no segfault, but an error message might be 
 printed
 instead:

e = tryCatch(stop(), error=identity)
sprintf('%s', e)
# segfault, choice of options
# ^c, stay in the session
e = tryCatch(stop(), error=identity)
sprintf('%s', e)
# segfault, immediate exit
  
e = tryCatch(stop(), error=identity)
sprintf('%s', e)
# segfault, choice of options
# ^c, stay in the session
e = tryCatch(stop(), error=identity)
x = 1 # possibly, whatever code would do
sprintf('%s', e)
# [1] Error in doTryCatch(return(expr), name, parentenv, handler): \n
# [2] Error in doTryCatch(return(expr), name, parentenv, handler): \n
sprintf('%s', e)
# segfault, immediate exit

 in the second code snippet above, on some executions the error message was
 printed. on others a segfault caused immediate exit.  (the pattern seems to
 differ between 2.8.0 and 2.10.0-devel.)

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