treewide: kill problematic "$h->{k} //= do {" assignments

As stated in the previous change, conditional hash assignments
which trigger other hash assignments seem problematic, at times.
So replace:

	$h->{k} //= do { $h->{x} = ...; $val };

	$h->{k} // do {
		$h->{x} = ...;
		$hk->{k} = $val
	};

"||=" is affected the same way, and some instances of "||=" are
replaced with "//=" or "// do {", now.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index 4a7ff2f4..58a0a9e3 100644
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -871,12 +871,12 @@ sub eml_index_offs_i { # PublicInbox::Eml::each_part callback
 # prepares an index for BODY[$SECTION_IDX] fetches
 sub eml_body_idx ($$) {
         my ($eml, $section_idx) = @_;
-        my $idx = $eml->{imap_all_parts} //= do {
+        my $idx = $eml->{imap_all_parts} // do {
                 my $all = {};
                 $eml->each_part(\&eml_index_offs_i, $all, 0, 1);
                 # top-level of multipart, BODY[0] not allowed (nz-number)
                 delete $all->{0};
-                $all;
+                $eml->{imap_all_parts} = $all;
         };
         $idx->{$section_idx};
 }