From d4c6760ad383a9419aef88be3abd479ebcfb6d36 Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Wed, 12 Oct 2011 20:28:21 -0700
Subject: [PATCH] Mention sort in warnings about sort sub retvals

With this commit,

$ ./miniperl -we '()=sort { undef } 1,2'
Use of uninitialized value at -e line 1.

becomes

$ ./miniperl -we '()=sort { undef } 1,2'
Use of uninitialized value in sort at -e line 1.
---
 pp_sort.c              | 4 ++++
 t/lib/warnings/9uninit | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/pp_sort.c b/pp_sort.c
index 8dacd74..fafa00a 100644
--- a/pp_sort.c
+++ b/pp_sort.c
@@ -1764,6 +1764,7 @@ S_sortcv(pTHX_ SV *const a, SV *const b)
     const I32 oldscopeix = PL_scopestack_ix;
     I32 result;
     PMOP * const pm = PL_curpm;
+    OP * const sortop = PL_op;
  
     PERL_ARGS_ASSERT_SORTCV;
 
@@ -1774,6 +1775,7 @@ S_sortcv(pTHX_ SV *const a, SV *const b)
     CALLRUNOPS(aTHX);
     if (PL_stack_sp != PL_stack_base + 1)
 	Perl_croak(aTHX_ "Sort subroutine didn't return single value");
+    PL_op = sortop;
     result = SvIV(*PL_stack_sp);
     while (PL_scopestack_ix > oldscopeix) {
 	LEAVE;
@@ -1792,6 +1794,7 @@ S_sortcv_stacked(pTHX_ SV *const a, SV *const b)
     I32 result;
     AV * const av = GvAV(PL_defgv);
     PMOP * const pm = PL_curpm;
+    OP * const sortop = PL_op;
 
     PERL_ARGS_ASSERT_SORTCV_STACKED;
 
@@ -1822,6 +1825,7 @@ S_sortcv_stacked(pTHX_ SV *const a, SV *const b)
     CALLRUNOPS(aTHX);
     if (PL_stack_sp != PL_stack_base + 1)
 	Perl_croak(aTHX_ "Sort subroutine didn't return single value");
+    PL_op = sortop;
     result = SvIV(*PL_stack_sp);
     while (PL_scopestack_ix > oldscopeix) {
 	LEAVE;
diff --git a/t/lib/warnings/9uninit b/t/lib/warnings/9uninit
index 2673b48..a30352a 100644
--- a/t/lib/warnings/9uninit
+++ b/t/lib/warnings/9uninit
@@ -632,6 +632,9 @@ my @sort;
 @sort = sort {$a <=> $b} $m1, $g1;
 sub sortf {$a-1 <=> $b-1};
 @sort = sort  &sortf, $m1, $g1;
+@sort = sort { undef } 1, 2;
+sub frobnicate($$) { undef }
+@sort = sort frobnicate 1, 2;
 EXPECT
 Use of uninitialized value $m1 in sort at - line 6.
 Use of uninitialized value $g1 in sort at - line 6.
@@ -649,6 +652,8 @@ Use of uninitialized value $m1 in sort at - line 9.
 Use of uninitialized value $m1 in sort at - line 9.
 Use of uninitialized value $g1 in sort at - line 9.
 Use of uninitialized value $g1 in sort at - line 9.
+Use of uninitialized value in sort at - line 10.
+Use of uninitialized value in sort at - line 11.
 ########
 use warnings 'uninitialized';
 my ($m1, $m2, $v);
-- 
2.7.4