Branch: refs/heads/blead
Home: https://github.com/Perl/perl5
Commit: a1d27354cdc17a77c95d1548cc9939dd6b8e1bb8
https://github.com/Perl/perl5/commit/a1d27354cdc17a77c95d1548cc9939dd6b8e1bb8
Author: Lukas Mai <[email protected]>
Date: 2026-07-16 (Thu, 16 Jul 2026)
Changed paths:
M sv.c
M t/lib/warnings/pp_hot
Log Message:
-----------
improve "uninitialized value" warning for multiconcat
The Perl code '$y = "foo" . length($x)' is compiled to a single
multiconcat op. When the code encounters an 'undef' value, it tries to
determine the source, which in this case must be length($x), propagating
undef from $x. But $y, the target of the assignment, is also one of
multiconcat's children, and was also considered a potential source of
undefs, preventing the right variable from being blamed.
This patch makes the scan for potential sources of undefs skip over
multiconcat's last child (the target) if OPf_STACKED is set.
Fixes #24460.
Commit: 2cfd97a418952481da0e0c933e071a8c0b9a1359
https://github.com/Perl/perl5/commit/2cfd97a418952481da0e0c933e071a8c0b9a1359
Author: Lukas Mai <[email protected]>
Date: 2026-07-16 (Thu, 16 Jul 2026)
Changed paths:
M sv.c
M t/lib/warnings/pp_hot
Log Message:
-----------
improve "uninitialized" warnings for append multiconcat
In the append case of multiconcat ($y .= "foo" . $x), the target $y is
an input to the operation, but can be skipped when scanning for undefs
because using .= on an uninitialized variable never triggers warnings.
So if a warning is to be emitted, we can blame some non-target child op.
Compare: https://github.com/Perl/perl5/compare/3657fe2672c8...2cfd97a41895
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