From @jdhedden

The code generated by 'find2perl' when the '-exec' directive is used
is faulty. A global variable for the current working directory ($cwd)
is not being set because its code occurs after the exit() call for the
generated script.

Here is an example of the generated code​:

<<< EXAMPLE STARTS >>>

  > find2perl.buggy . -name '*.pl' -exec grep -H BUGUS '{}' ';'
  #! /usr/bin/perl -w
  eval 'exec /usr/bin/perl -S $0 ${1+"$@​"}'
  if 0; #$running_under_some_shell

  use strict;
  use File​::Find ();

  # Set the variable $File​::Find​::dont_use_nlink if you're using
AFS,
  # since AFS cheats.

  # for the convenience of &wanted calls, including -eval
statements​:
  use vars qw/*name *dir *prune/;
  *name = *File​::Find​::name;
  *dir = *File​::Find​::dir;
  *prune = *File​::Find​::prune;

  sub wanted;
  sub doexec ($@​);

  # Traverse desired filesystems
  File​::Find​::find({wanted => \&wanted}, '.');
  exit;

  sub wanted {
  /^.*\.pl\z/s &&
  doexec(0, 'grep','-H','BUGUS','{}');
  }

  use Cwd ();
  my $cwd = Cwd​::cwd();

  sub doexec ($@​) {
  my $ok = shift;
  my @​command = @​_; # copy so we don't try to s/// aliases to
constants
  for my $word (@​command)
  { $word =~ s#{}#$name#g }
  if ($ok) {
  my $old = select(STDOUT);
  $| = 1;
  print "@​command";
  select($old);
  return 0 unless <STDIN> =~ /^y/;
  }
  chdir $cwd; #sigh
  system @​command;
  chdir $File​::Find​::dir;
  return !$?;
  }

<<< EXAMPLE ENDS >>>

Note in the above that the lines​:

  use Cwd ();
  my $cwd = Cwd​::cwd();

occur after​:

  File​::Find​::find({wanted => \&wanted}, '.');
  exit;

As a result $cwd never gets set, and causes errors when the doexec()
function is executed, as in the following​:

<<< EXAMPLE STARTS >>>

  > find2perl.buggy . -name '*.pl' -exec grep -H BUGUS '{}' ';' |
perl
  Use of uninitialized value in chdir at - line 48.
  Use of chdir('') or chdir(undef) as chdir() is deprecated at -
line 48.
  Use of uninitialized value in chdir at - line 48.
  Use of chdir('') or chdir(undef) as chdir() is deprecated at -
line 48.
  Use of uninitialized value in chdir at - line 48.
  ...

<<< EXAMPLE ENDS >>>

I have verified that this bug is present in the following Perl
distributions​:
  5.6.2
  5.8.3
  5.9.1

I have a fix for this bug. The following is a diff of 'find2perl' as
installed from the Perl 5.9.1 distribution​:

<<< DIFF STARTS >>>

  259a260,267
  > if (exists $init{doexec}) {
  > print <<'END';
  > use Cwd ();
  > my $cwd = Cwd​::cwd();
  >
  > END
  > }
  >
  327,330d334
  <
  < use Cwd ();
  < my $cwd = Cwd​::cwd();
  <

<<< DIFF ENDS >>>

This fix will work with all the versions of 'find2perl' in the
distributions that I examined. As the 'diff' lines will differ
between version, the following shows the code changes with bracketing
lines from the 'find2perl' script​:

<<< FIRST CODE SECTION STARTS >>>

  $declaresubs

  END

  ### The following block needs to be added ###
  if (exists $init{doexec}) {
  print <<'END';
  use Cwd ();
  my $cwd = Cwd​::cwd();

  END
  }
  ### (end block) ###

  if (exists $init{ls}) {
  print <<'END';

<<< FIRST CODE SECTION ENDS >>>

<<< SECOND CODE SECTION STARTS >>>

  if (exists $init{doexec}) {
  print <<'END';

  ### The following two lines need to be removed ###
  use Cwd ();
  my $cwd = Cwd​::cwd();
  ### (end remove) ###

  sub doexec ($@​) {

<<< SECOND CODE SECTION ENDS >>>

Thank you,
Jerry D. Hedden

From @iabyn

On Thu, Mar 18, 2004 at 08​:25​:50PM -0000, jdhedden@​1979.usna.com (via RT) wrote​:

The code generated by 'find2perl' when the '-exec' directive is used
is faulty. A global variable for the current working directory ($cwd)
is not being set because its code occurs after the exit() call for the
generated script.

Thanks, your patch has been applied to the development veersion of Perl as
change #22586.

NB​: in case you submit any future patches, it is easier for us if you
generate it using diff -u, or if the -u option isn't supported, diff -c.

Dave.

--
The perl5 internals are a complete mess. It's like Jenga - to get the
perl5 tower taller and do something new you select a block somewhere in
the middle, with trepidation pull it out slowly, and then carefully
balance it somewhere new, hoping the whole edifice won't collapse as a
result.
  - Nicholas Clark, based on an original by Simon Cozens.

The RT System itself - Status changed from 'new' to 'open'

@iabyn - Status changed from 'open' to 'resolved'