Branch: refs/heads/blead
Home: https://github.com/Perl/perl5
Commit: 658a5bedcfb012a503b61de6c8cb69924cc6f6f8
https://github.com/Perl/perl5/commit/658a5bedcfb012a503b61de6c8cb69924cc6f6f8
Author: Richard Leach <richardle...@users.noreply.github.com>
Date: 2022-09-14 (Wed, 14 Sep 2022)
Changed paths:
M sv.c
Log Message:
-----------
Perl_sv_setsv_flags: return after invlist_clone case
In the "first_ switch" statement in Perl_sv_setsv_flags, there's this case:
case SVt_INVLIST:
invlist_clone(ssv, dsv);
break;
When the INVLIST code was added, it was unclear whether the logic following
that switch needed to apply to INVLISTs or not. Early returns were also seen
as risky from a future maintenance perspective. As a precaution, this case
was written to `break` rather than `return`.
With later analysis though, it seems like the code below this switch does
not apply to INVLISTs, apart from one unintended interaction.
* invlist_clone() - in regcomp.c - copies the PV buffer of ssv to dsv.
* However, whenever an invlist is initialized, SvPOK_on is called on its SV;
according to the nearby comment "/* This allows B to extract the PV */".
* Because the switch case does not return, the later `if (sflags & SVp_POK)`
branch will try to swipe/cow/copy the PV buffer of ssv to dsv. This is an
unnecessary double copy.
On that analysis, this commit changes the break into a return.
