in reply to Re^2: Side Effects
in thread Side Effects

OK, here's what I'm thinking. 
$Body .= $_ while <LOG>;

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is equivalent to 
while ($_ = <LOG>)
{
   $Body .= $_;
}

[download]
Therefore, $_ is both an L-value and an R-value. If we assume for a moment that $_ is somehow an alias for $g::TaskList, then it should be correct that for each iteration of the while loop, $_ (and thus $g::TaskList) will get assigned the next line from <LOG>. At the end of the while loop, what would happen to $_? Would it get undef'd? Would this undef any aliases? So, let's assume all this is true... Here is my code path: 
In Localize.pm:
(SNIP)
    foreach my $lang (@g::LanguageList)
    {
        $g::Language = $lang;
    unless (isExcludedBuild($g::Product, $g::Architecture, $g::Flavor)
+ || $g::Architecture =~ /ia64/i || $g::Language =~ /usa/i)
    {
(SNIP)                                &BuildBlah();
        }
    }
(SNIP)
                
In Utilities.pm:
sub BuildBlah {
    my $FlavorVariation = shift;
(snip)

    if(FileExists("Blah"))
    {
        SendMail($g::MailPurpose{"BuildFailed"}, "Blah", $FlavorVariat
+ion);    
    }
(snip)
}

In Reporting.pm:
sub SendMail {
    my $Purpose = shift;
    my @OptionalParameters = @_;    
        my $Body = "";  
(snip)
    $Body = "<html> <body background=nothing bgproperties=\"fixed\">";

    if($Purpose eq $g::MailPurpose{BuildNominated})
    {
(snip)
        }
    elsif($Purpose eq $g::MailPurpose{BuildFailed})
    {
(snip)
        open(LOG, "$LogDir\\$g::BuildErrFile");
        while (my $line = <LOG>)
        {
            $Body .= "${line}<br>";
        }
        close LOG;

    }

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Although I've snipped a lot of code, this follows the execution path, and you can see that $g::TaskList is never mentioned going way way back up through several loops, modules and subroutine calls. Do I need to backtrack further? I would think the foreach above would wipe out any alias of $_ to TaskList that might have been set higher up in the stack trace.

In Section Seekers of Perl Wisdom