Destruction of constants in unreviewed branches

Question

Perl's explicit behavior is to iron out the constants in the branches left after the branch was trimmed, based on the broken state. Is this documented?

This outputs 1:

bash$ T="" perl -Tle '

use constant T=>$ENV{T};
use Scalar::Util qw/tainted/;
exit if T;
print tainted(0)'

It seems that the constant is 0spoiled, because everything after the exit (in the original problem it was a return) is in the branch, which remains after the branching, which occurred on the basis of the spoiled state. This is a very cool Perl taint mode feature, but I can't find the documentation anywhere. If the parameter is $ENV{T}not set or when the condition is on dynamic access to $ENV{T}, the constants are not corrupted.

By the way, the best answer that I know at this time about the supposed actual problem of software development, from which this question arises, about how to disable part of the taint-mode perl-mode source during development without infecting my constants, is , set a constant to a constant instead of a damaged environment variable, for example:

use constant DEBUG_MODE => ( $ENV{DEV_DEBUG} ? 1 : 0 );

Answer 1

, , , , perl- perl-mode , , :

use constant DEBUG_MODE => ( $ENV{DEV_DEBUG} ? 1 : 0 );