perl/perl-5.29.0-treat-when-index-1-as-a-boolean-expression.patch

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From 6b877bbd2c071b3e0659fab552a74dc2ff7e08fb Mon Sep 17 00:00:00 2001
From: David Mitchell <davem@iabyn.com>
Date: Sat, 14 Jul 2018 10:47:04 +0100
Subject: [PATCH] treat when(index() > -1) as a boolean expression
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RT #133368
when(X) is normally compiled as when($_ ~~ X) *except* when X appears to
be a boolean expression, in which case it's used directly.
5.28.0 introduced an optimisation whereby comparisons involving index
like
index(...) != -1
eliminated the comparison, and pp_index() returned a boolean value
directly. This defeated the 'look for a boolean op' mechanism, and so
when(index(...) != -1)
and similar were being incorrectly compiled as
when($_ ~~ (index(...) != -1))
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
op.c | 8 +++++++-
t/op/switch.t | 23 ++++++++++++++++++++++-
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/op.c b/op.c
index a05a1319d4..ddeb484b64 100644
--- a/op.c
+++ b/op.c
@@ -9072,6 +9072,13 @@ S_looks_like_bool(pTHX_ const OP *o)
case OP_FLOP:
return TRUE;
+
+ case OP_INDEX:
+ case OP_RINDEX:
+ /* optimised-away (index() != -1) or similar comparison */
+ if (o->op_private & OPpTRUEBOOL)
+ return TRUE;
+ return FALSE;
case OP_CONST:
/* Detect comparisons that have been optimized away */
@@ -9081,7 +9088,6 @@ S_looks_like_bool(pTHX_ const OP *o)
return TRUE;
else
return FALSE;
-
/* FALLTHROUGH */
default:
return FALSE;
diff --git a/t/op/switch.t b/t/op/switch.t
index e5385df0b4..6ff69e0bce 100644
--- a/t/op/switch.t
+++ b/t/op/switch.t
@@ -10,7 +10,7 @@ use strict;
use warnings;
no warnings 'experimental::smartmatch';
-plan tests => 195;
+plan tests => 197;
# The behaviour of the feature pragma should be tested by lib/feature.t
# using the tests in t/lib/feature/*. This file tests the behaviour of
@@ -1358,6 +1358,27 @@ given("xyz") {
"scalar value of false when";
}
+# RT #133368
+# index() and rindex() comparisons such as '> -1' are optimised away. Make
+# sure that they're still treated as a direct boolean expression rather
+# than when(X) being implicitly converted to when($_ ~~ X)
+
+{
+ my $s = "abc";
+ my $ok = 0;
+ given("xyz") {
+ when (index($s, 'a') > -1) { $ok = 1; }
+ }
+ ok($ok, "RT #133368 index");
+
+ $ok = 0;
+ given("xyz") {
+ when (rindex($s, 'a') > -1) { $ok = 1; }
+ }
+ ok($ok, "RT #133368 rindex");
+}
+
+
# Okay, that'll do for now. The intricacies of the smartmatch
# semantics are tested in t/op/smartmatch.t. Taintedness of
# returned values is checked in t/op/taint.t.
--
2.14.4