尝试修改只读值开始出现在脚本中

Question

我试图弄清楚为什么这个错误会出现在Perl脚本中：

A fatal error has occured:
    Modification of a read-only value attempted at (eval 7) line 10.
Please enable debugging in setup for more details.

当我从命令行运行它时：

perl -d admin.cgi

它死的点是：

<p><font face='Tahoma,Arial,Helvetica' size=2>A fatal error has occured:</font></p><blockquote><pre>Modification of a read-only value attempted at (eval 14)[/home/user/public_html/cgi-bin/links/admin/GT/AutoLoader.pm:128] line 10.
</pre></blockquote><p><font face='Tahoma,Arial,Helvetica' size=2>Please enable debugging in setup for more details.</font></p>
Modification of a read-only value attempted at (eval 14)[/home/user/web/example.com/public_html/cgi-bin/links/admin/GT/AutoLoader.pm:128] line 10.
Debugged program terminated.  Use q to quit or R to restart,

查看 AutoLoader.pm 文件，我在第 128 行看到这个：

eval "package $pkg;n#line $linenum$pkg::$funcn$COMPILE->{$func}";

如果我添加更多调试：

print "FOO: $pkg ($func)n";

然后我在运行时看到这个：

FOO: GT::Template (_call_func)
FOO: GT::CGI (html_escape)
FOO: GT::Base (in_eval)
<p><font face='Tahoma,Arial,Helvetica' size=2>A fatal error has occured:</font></p><blockquote><pre>Modification of a read-only value attempted at (eval 7) line 10.
</pre></blockquote><p><font face='Tahoma,Arial,Helvetica' size=2>Please enable debugging in setup for more details.</font></p>
Modification of a read-only value attempted at (eval 7) line 10.

脚本在昨天的整个过程中都运行良好，我认为我没有更改任何会导致这种情况的东西 - 所以我有点不知所措。

更新：经过更多的挖掘，我发现它来自另一个模块中的这一行：

my $output = $code->($self);

$code似乎来自上面的一点：

my $root      = $self->{root};
my $full_file = $self->{root} . '/' . $template;
my ($code, $dont_save, $files) = $self->{opt}->{print} == 2
    ? @{$FILE_CACHE_PRINT{$full_file}}{qw/code dont_save files/}
    : @{$FILE_CACHE{$full_file}}{qw/code dont_save files/};

更新 2：根据要求，以下是print STDERR qq|package $pkg;n#line $linenum$pkg::$funcn$COMPILE->{$func}n|;的输出：

package GT::Base;
#line 538GT::Base::in_eval
sub in_eval {
# -------------------------------------------------------
# Current perl has a variable for it, old perl, we need to look
# through the stack trace. Ugh.
#
    my $ineval;
    if ($] >= 5.005 and !MOD_PERL) { $ineval = defined($^S) ? $^S : (stack_trace('GT::Base',1) =~ /(eval)/) }
    elsif (MOD_PERL) {
        my $stack = stack_trace('GT::Base', 1);
        $ineval = $stack =~ m{
            (eval)
            (?!
                s+called ats+
                (?:
                    /dev/null
                |
                    -e
                |
                    /S*/(?:Apache2?|ModPerl)/(?:Registry(?:Cooker)?|PerlRun).pm
                |
                    PerlHandler subroutine `(?:Apache2?|ModPerl)::Registry
                )
            )
        }x;
    }
    else {
        my $stack = stack_trace('GT::Base', 1);
        $ineval   = $stack =~ /(eval)/;
    }
    return $ineval;
}

<p><font face='Tahoma,Arial,Helvetica' size=2>A fatal error has occured:</font></p><blockquote><pre>Modification of a read-only value attempted at (eval 7) line 10.
</pre></blockquote><p><font face='Tahoma,Arial,Helvetica' size=2>Please enable debugging in setup for more details.</font></p>
Modification of a read-only value attempted at (eval 7) line 10.

Answer 1

啊，伙计 - 找到了！在站点配置中，它发生了一些奇怪的事情：

'db_cgi_url' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url.' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url..' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url...' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url....' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url.....' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url......' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url.......' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url........' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url.........' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url..........' => 'http://m.example.com/cgi-bin/links',
'db_cgi_url...........' => 'http://m.example.com/cgi-bin/links',

其他地方一定有东西在更新它，而我没有要求它。不在mod_perl下的前端似乎还可以，因为它使用的是缓存版本的 Data.pm

谢谢大家！