p5pRT
commented
20 years ago From wolf-dietrich.moeller@siemens.com
Wrong assignment in nested assignment together with subroutine call.
Given one assignment with a concatenation on the right hand side. The first term of this concatenation is an assignment of a concatenation\, enclosed in parentheses.
If the inner assignment concatenates two constant strings or scalar variables\, everything is okay. Example statement: $x2 = ($x1 = '##'.'**').'++';
If the inner assignment assigns the concatenation of a string and the result of a subroutine call\, then the parentheses are not honored correctly. Example statement: $x2 = ($x1 = '##'.fct('**')).'++'; The "inner" result variable $x1 has (incorrectly) the value of the "outer" result varable ($x2).
If a "dummy" empty string is concatenated at the beginning of the outer concatenation\, then the behaviour is correct. Example statement: $x2 = ''.($x1 = '##'.fct '**' ).'++';
Working test examples\, sample output\, and Perl version info see test program below.
######################### start test program ####################### #!/usr/local/bin/perl # test-script to show error # Wolf-Dietrich Moeller\, 2003-11-14\, \mailto​:wolf\-dietrich\.moeller@​siemens\.com # tested on Perl 5.8.0_806 and 5.8.1_807 Win32 ActiveState\, # also on Perl 5.6.1 under Apache webserver and freeBSD (source distribution) # output is (for command line and CGI-script): ####################################################### #1 x1=##** x2=##**++ #2 x1=##**++ x2=##**++ #3 x1=##**++ x2=##**++ #4 x1=##** x2=##**++ #5 x1=##** x2=##**++ # error in lines 2 and 3: x1 should always equal '##**' ####################################################### use strict; binmode STDOUT; sub fct ($) { my $c = shift; return $c } my ($x1\,$x2); print "Content-Type: text/plain\x0D\x0A\x0D\x0A"; # # compound statement without sub $x2 = ($x1 = '##'.'**').'++'; print '#1 x1='\,$x1\,' x2='\,$x2\,"\x0D\x0A"; # # compound statement with sub $x2 = ($x1 = '##'.fct '**' ).'++'; print '#2 x1='\,$x1\,' x2='\,$x2\,"\x0D\x0A"; # # compound statement with sub (parentheses for parameters added) $x2 = ($x1 = '##'.fct('**')).'++'; print '#3 x1='\,$x1\,' x2='\,$x2\,"\x0D\x0A"; # # (empty) concatenation in front of inner assignment added $x2 = ''.($x1 = '##'.fct '**' ).'++'; print '#4 x1='\,$x1\,' x2='\,$x2\,"\x0D\x0A"; # # two simple statements $x1 = '##'.fct('**'); $x2 = $x1.'++'; print '#5 x1='\,$x1\,' x2='\,$x2\,"\x0D\x0A"; # print "# error in lines 2 and 3: x1 should always equal '##**'\x0D\x0A"; ###################### end test program #############################
Dr. Wolf-Dietrich Moeller Siemens AG\, CT IC 3\, D-81730 München Corporate Technology Department Security Mch P\, Tel. +49 89 636-53391\, Fax -48000 mailto:wolf-dietrich.moeller@siemens.com Intranet https://security.ct.siemens.de/
Migrated from rt.perl.org#24508 (status was 'resolved')
Searchable as RT24508$