Re: Automatic stack traces for warns and dies

[itub]

Something that I find useful for this is diagnostics, which comes with Perl. This pragma is famous for giving verbose explanations for all kinds of errors, but perhaps it is not so well known that it also prints the stack trace upon dying. For example,

# div_by_zero.pl
sub a { b(@_) }
sub b { c(@_) }
sub c { 1/shift };
a(0);

The output:

$ perl div_by_zero.pl
Illegal division by zero at div_by_zero.pl line 4.

$ perl -Mdiagnostics div_by_zero.pl
Illegal division by zero at div_by_zero.pl line 3 (#1)
    (F) You tried to divide a number by 0.  Either something was wrong in
    your logic, or you need to put a conditional in to guard against
    meaningless input.
    
Uncaught exception from user code:
        Illegal division by zero at div_by_zero.pl line 3.
        main::c(0) called at div_by_zero.pl line 2
        main::b(0) called at div_by_zero.pl line 1
        main::a(0) called at div_by_zero.pl line 4

Update: Note that stack traces for warnings are not printed.

[fergal]

Thanks for that, a patch has just been added to bleadperl to allow

perl -Mdiagnostics=-t,-w some_bad_script

-t will suppress the explanations and -w will add stack traces to your warns.