Prevent "use sort 'stable'" from reversing the order

Message-ID: <20060402162024.GA3854@rpc142.cs.man.ac.uk>

p4raw-id: //depot/perl@27689

2 files changed, 5 insertions, 2 deletions

diff --git a/lib/sort.t b/lib/sort.t
index 62c5529c21..ca809b0ffa 100644
--- a/lib/sort.t
+++ b/lib/sort.t
@@ -26,7 +26,7 @@ use strict;
 use warnings;
 
 use Test::More tests => @TestSizes * 2	# sort() tests
-			* 4		# number of pragmas to test
+			* 6		# number of pragmas to test
 			+ 1 		# extra test for qsort instability
 			+ 3		# tests for sort::current
 			+ 3;		# tests for "defaults" and "no sort"
@@ -163,16 +163,19 @@ main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
     no sort qw(_qsort);
     my $sort_current; BEGIN { $sort_current = sort::current(); }
     is($sort_current, 'stable', 'sort::current after no _qsort');
+    main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
 }
 
 {
     use sort qw(defaults _qsort);
     my $sort_current; BEGIN { $sort_current = sort::current(); }
     is($sort_current, 'quicksort', 'sort::current after defaults _qsort');
+    # Not expected to be stable, so don't test for stability here
 }
 
 {
     use sort qw(defaults stable);
     my $sort_current; BEGIN { $sort_current = sort::current(); }
     is($sort_current, 'stable', 'sort::current after defaults stable');
+    main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
 }
diff --git a/pp_sort.c b/pp_sort.c
index 6e03d0e839..aa1fe80929 100644
--- a/pp_sort.c
+++ b/pp_sort.c
@@ -363,7 +363,7 @@ S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
 
     if (nmemb <= 1) return;			/* sorted trivially */
 
-    if (flags) {
+    if ((flags & SORTf_DESC) != 0) {
 	savecmp = PL_sort_RealCmp;	/* Save current comparison routine, if any */
 	PL_sort_RealCmp = cmp;	/* Put comparison routine where cmp_desc can find it */
 	cmp = cmp_desc;