Crash in example part by callig ERROR

[gorzel]

Wenn eine proc mittels ERROR austeigt, und diese proc von ihrem example part aufgerufen wird, so kommt es zum Absturz, wenn zuvor eine proc aufgerufen wurde, die ein poly zurueck gibt.

Die lokalen Objekte des example parts werden in dem Fall nicht geloescht.

Der Fehler ist sehr seltsam!

Hier die library bug.lib

version = "$Id: bug.lib,v 1.0 2010/02/19 q$";

category = "general";
info =
" 
LIBRARY: bug.lib, Shows a bug with example
AUTHOR:  Christian Gorzel, University of Muenster
email: gorzelc@math.uni-muenster.de

PROCEDURES:

     callbug()  shows an bug with example 
";

////////////////////////////////////////////////////////////

proc callbug(poly f)
"USAGE: callbug(f); f poly   
RETURN: poly
NOTE:            
EXAMPLE: example callbug; shows an example
"
{
  ERROR("cannot transform.");
  return(f);
}
example
{ "EXAMPLE:"; echo =2;
   int n = 123456789;
   ring r3 = 3,(x,y),dp;
   poly g = xy;
   callbug(g);
}
///////////////////////////////////////////////////////////////

Nun der Aufruf:

LIB"bug.lib";
int i =1;
proc callobj(def obj) {return(obj);}
;
example callbug;     
listvar();        // local objects from example part no longer exist
;
ring R=0,x,dp;
example callbug;
listvar();         // local objects from example part no longer exist
;
callobj(x);
example callbug;
listvar();        // local objects from example part still exist
;

Die Ausgabe ist:

> LIB"bug.lib";
// ** loaded /home/gorzelc/bug.lib (1.0,2010/02/19)
> int i =1;
> proc callobj(def obj) {return(obj);}
> ;
> example callbug;     
// proc callbug from lib bug.lib
EXAMPLE:
   int n = 123456789;
   ring r3 = 3,(x,y),dp;
   poly g = xy;
   callbug(g);
   ? cannot transform.
   ? leaving bug.lib::callbug
   ? leaving bug.lib::callbug
> listvar();        // local objects from example part no longer exist
// i                    [0]  int 1
> ;
> ring R=0,x,dp;
> example callbug;
// proc callbug from lib bug.lib
EXAMPLE:
   int n = 123456789;
   ring r3 = 3,(x,y),dp;
   poly g = xy;
   callbug(g);
   ? cannot transform.
   ? leaving bug.lib::callbug
   ? leaving bug.lib::callbug
> listvar();         // local objects from example part no longer exist
// R                    [0]  *ring
// i                    [0]  int 1
> ;
> callobj(x);
x
> example callbug;
// proc callbug from lib bug.lib
EXAMPLE:
   int n = 123456789;
   ring r3 = 3,(x,y),dp;
   poly g = xy;
   callbug(g);
   ? cannot transform.
   ? leaving bug.lib::callbug
   ? leaving bug.lib::callbug
   ? return value depends on local ring variable (export missing ?)
Singular : signal 11 (v: 3119/2010021205):
current line:>>     ERROR("cannot transform the polynomial.");<<
Segment fault/Bus error occurred at 84f8406 because of c (r:1266589812)
please inform the authors
trying to restart...
. listvar();          // local objects from example part still exist
STDIN  15. listvar();          // local objects from example part still exist
// r3                   [1]  *ring
// n                    [1]  int 123456789
// R                    [0]  ring
// i                    [0]  int 1
> ;
STDIN  16> ;

Beachte die zeile "export missing"

   ? leaving bug.lib::callbug
   ? return value depends on local ring variable (export missing ?)
Singular : signal 11 (v: 3119/2010021205):

Desweiteren: Weshalb ergibt sich stets eine doppelte Meldung von

   ? leaving bug.lib::callbug
   ? leaving bug.lib::callbug

[gorzel]

bug.lib

[gorzel]

input file for the bug demo

[hannes]

return value filed was nor initialized for examples (they usually do not return anything).