remove assertion that collation magic has data

This broke on some smokers where the locale collation data was
broken in some way (and rejected by the collation setup code.)

It also broke if collation magic was generated for an SV and then
the SV was modified, freeing the collation data before the SV was
destroyed.

2 files changed, 31 insertions, 3 deletions

diff --git a/mg.c b/mg.c
index d14b2eb88c..32d7732bc6 100644
--- a/mg.c
+++ b/mg.c
@@ -2669,9 +2669,12 @@ Perl_magic_freecollxfrm(pTHX_ SV *sv, MAGIC *mg)
     /* Collate magic uses mg_len as a string length rather than a buffer
      * length, so we need to free even with mg_len == 0: hence we can't
      * rely on standard magic free handling */
-    assert(mg->mg_type == PERL_MAGIC_collxfrm && mg->mg_len >= 0);
-    Safefree(mg->mg_ptr);
-    mg->mg_ptr = NULL;
+    if (mg->mg_len >= 0) {
+        assert(mg->mg_type == PERL_MAGIC_collxfrm);
+        Safefree(mg->mg_ptr);
+        mg->mg_ptr = NULL;
+    }
+
     return 0;
 }
 #endif /* USE_LOCALE_COLLATE */
diff --git a/t/run/locale.t b/t/run/locale.t
index 78cfc2ff72..e072b63b0f 100644
--- a/t/run/locale.t
+++ b/t/run/locale.t
@@ -510,4 +510,29 @@ EOF
 
 }
 
+SKIP:
+{
+    use locale;
+    # look for an english locale (so a < B, hopefully)
+    my ($en) = grep /^en_/, @locales;
+    POSIX::setlocale(LC_COLLATE, $en);
+    unless ("a" lt "B") {
+        skip "didn't find a suitable locale", 1;
+    }
+    fresh_perl_is(<<'EOF', "ok\n", { args => [ $en ] }, "check for failed assertion");
+use locale ':collate';
+use POSIX qw(setlocale LC_COLLATE);
+if (setlocale(LC_COLLATE, shift)) {
+     my $x = "a";
+     my $y = "B";
+     print $x lt $y ? "ok\n" : "not ok\n";
+     $x = "c"; # should empty the collxfrm magic but not remove it
+     # which the free code asserts on
+}
+else {
+     print "ok\n";
+}
+EOF
+}
+
 done_testing();