p5pRT
commented
8 years ago From sullr@cpan.org
Created by sullr@cpan.org
The following statement gets successfully parsed and executed by perl. Note that at the end of line 3 there is a '.' instead of a ';'\, i.e. the author of the code made obviously an error (based on real bug).
1 my $x = 1; 2 my $y = 'a'; 3 warn "foobar $y " . "foo " . 4 $x = 0;
> 0 at x.pl line 3.
If the code is modified so that the first concationation is skipped the behavior is completly different but actually the expected behavior (i.e. error):
1 my $x = 1; 2 my $y = 'a'; 3 warn "foobar $y foo " . 4 $x = 0;
> Can't modify concatenation (.) or string in scalar assignment at x.pl line 4\, near "0;" > Execution of x.pl aborted due to compilation errors.
The same behavior can be seen with assignments\, i.e.
my $z = "foobar $y " . "foo " . $x = 0; # works\, $z is 0 my $z = "foobar $y foo " . $x = 0; # error
It also works if the variable is outside the quotes or even if no quotes at all are used but an additional variable.
my $z = $x = 0; # works as expected my $z = $y.$x = 0; # fails as expected my $z = "".$y.$x = 0; # works unexpectedly my $z = $y."".$x = 0; # works unexpectedly my $z = $v.$y.$x = 0; # works unexpectedly
This behavior exists in a wide range of perl versions. I found it in perl 5.8.1 and it is still in the current blead perl 5.25.5.
Migrated from rt.perl.org#129233 (status was 'open')
Searchable as RT129233$