eml: fix leak workaround

Our previous workaround didn't actually work around the leak in
<https://rt.cpan.org/Public/Bug/Display.html?id=139622> since
croak()-via-Perl was still invoked before the SV reference
count could be decremented.

Put in a proper workaround which saves warnings onto a temporary
variable and only croak after ->decode or ->encode returns; not
inside those methods.

diff --git a/lib/PublicInbox/Eml.pm b/lib/PublicInbox/Eml.pm
index 69c26932f65162d76696a067c69243ef2f90e224..3c681ba5bc2eb6efc6b0252b67a26ebd2f3b6904 100644 (file)
--- a/lib/PublicInbox/Eml.pm
+++ b/lib/PublicInbox/Eml.pm
@@ -333,15 +333,18 @@ sub body_set {
 }
 
 sub body_str_set {
-       my ($self, $body_str) = @_;
+       my ($self, $str) = @_;
        my $cs = ct($self)->{attributes}->{charset} //
                croak('body_str was given, but no charset is defined');
        my $enc = find_encoding($cs) // croak "unknown encoding `$cs'";
-       $body_str = do {
-               local $SIG{__WARN__} = \&croak;
-               $enc->encode($body_str, Encode::FB_WARN);
+       my $tmp;
+       {
+               my @w;
+               local $SIG{__WARN__} = sub { push @w, @_ };
+               $tmp = $enc->encode($str, Encode::FB_WARN);
+               croak(@w) if @w;
        };
-       body_set($self, \$body_str);
+       body_set($self, \$tmp);
 }
 
 sub content_type { scalar header($_[0], 'Content-Type') }
@@ -466,8 +469,11 @@ sub body_str {
        my $enc = find_encoding($cs) or croak "unknown encoding `$cs'";
        my $tmp = body($self);
        # workaround https://rt.cpan.org/Public/Bug/Display.html?id=139622
-       local $SIG{__WARN__} = \&croak;
-       $enc->decode($tmp, Encode::FB_WARN);
+       my @w;
+       local $SIG{__WARN__} = sub { push @w, @_ };
+       my $ret = $enc->decode($tmp, Encode::FB_WARN);
+       croak(@w) if @w;
+       $ret;
 }
 
 sub as_string {