[perl #92728] open.pm without :std should leave std alone

‘use open’ without :std was turning off layers on STDIN and STDOUT
(but not STDERR), due to a few missing if() conditions and due to an
omission of STDERR (which probably also caused STDERR’s handles to
accumulate through multiple calls to ‘use open ':std'...’).

This fixes that.  (As if you were expecting otherwise.)

2 files changed, 28 insertions, 6 deletions

diff --git a/lib/open.pm b/lib/open.pm
index 1bfe0d6833..d3f2d1bac8 100644
--- a/lib/open.pm
+++ b/lib/open.pm
@@ -1,7 +1,7 @@
 package open;
 use warnings;
 
-our $VERSION = '1.08';
+our $VERSION = '1.09';
 
 require 5.008001; # for PerlIO::get_layers()
 
@@ -95,16 +95,22 @@ sub import {
 	    }
 	}
 	if ($type eq 'IN') {
-	    _drop_oldenc(*STDIN, @val);
+	    _drop_oldenc(*STDIN, @val) if $std;
 	    $in  = join(' ', @val);
 	}
 	elsif ($type eq 'OUT') {
-	    _drop_oldenc(*STDOUT, @val);
+	    if ($std) {
+		_drop_oldenc(*STDOUT, @val);
+		_drop_oldenc(*STDERR, @val);
+	    }
 	    $out = join(' ', @val);
 	}
 	elsif ($type eq 'IO') {
-	    _drop_oldenc(*STDIN,  @val);
-	    _drop_oldenc(*STDOUT, @val);
+	    if ($std) {
+		_drop_oldenc(*STDIN, @val);
+		_drop_oldenc(*STDOUT, @val);
+		_drop_oldenc(*STDERR, @val);
+	    }
 	    $in = $out = join(' ', @val);
 	}
 	else {
diff --git a/lib/open.t b/lib/open.t
index f9cacab8a1..586d8e2c38 100644
--- a/lib/open.t
+++ b/lib/open.t
@@ -7,7 +7,7 @@ BEGIN {
 	require './test.pl';
 }
 
-plan 23;
+plan 24;
 
 # open::import expects 'open' as its first argument, but it clashes with open()
 sub import {
@@ -195,6 +195,22 @@ SKIP: {
 	 "test for an endless loop in PerlIO_find_layer");
 }
 
+is runperl(
+     progs => [
+        'use open q\:encoding(UTF-8)\, q-:std-;',
+        'use open q\:encoding(UTF-8)\;',
+        'if(($_ = <STDIN>) eq qq-\x{100}\n-) { print qq-stdin ok\n- }',
+        'else { print qq-got -, join(q q q, map ord, split//), "\n" }',
+        'print STDOUT qq-\x{ff}\n-;',
+        'print STDERR qq-\x{ff}\n-;',
+     ],
+     stdin => "\xc4\x80\n",
+     stderr => 1,
+   ),
+   "stdin ok\n\xc3\xbf\n\xc3\xbf\n",
+   "use open without :std does not affect standard handles",
+;
+
 END {
     1 while unlink "utf8";
     1 while unlink "a";