fix: preserve weakrefs in iterative clone path past MAX_DEPTH

[Koan-Bot]

What

Weakened references inside deeply nested array chains (past MAX_DEPTH) now preserve their weak status when cloned.

Why

The iterative clone fallback (av_clone_iterative) creates RVs via newRV_noinc without checking SvWEAKREF on the original reference. This silently converts weak references to strong ones in the clone — a correctness issue that breaks refcount-based lifetime management for structures cloned past the recursion depth limit.

The same issue existed at the sv_clone MAX_DEPTH entry points for RV-to-AV and RV-to-HV, where the wrapping RV didn't preserve weakness.

How

Added SvWEAKREF checks at three sites:

• av_clone_iterative chain-walking loop (chain links and circular-ref/leaf handlers)
• sv_clone MAX_DEPTH block (RV-to-AV and RV-to-HV entry points)

Weak RVs are pushed to the deferred weakrefs array for batch weakening at the end, matching the pattern used by the recursive path and rv_clone_iterative.

Testing

New test file t/22-weakref-iterative.t (8 subtests):

• Weakref deep inside the iterative zone with strong anchor (survives deferred weakening)
• Weakref at the sv_clone MAX_DEPTH entry point boundary
• All existing tests pass (make test clean)

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Quality Report

Changes: 3 files changed, 130 insertions(+), 3 deletions(-)

Code scan: clean

Tests: passed (OK)

Branch hygiene: clean

Generated by Kōan post-mission quality pipeline

[atoomic]

Looks like we are introducing a boilerplate here
this would need to be factorize using an helper or a macro to make the code easier to read/maintain and avoiding x4 times the same block of code

[Koan-Bot]

Addressed in the rebase — the repeated if (SvWEAKREF(...)) av_push(weakrefs, SvREFCNT_inc_simple_NN(...)) pattern is now factored into the CLONE_TRACK_WEAKREF(src, rv, weakrefs) macro (defined at line 44, near the other CLONE_* macros). All five call sites use the macro. One minor follow-up: the macro parameters aren't parenthesized at their use sites — not a problem today since all callers pass simple identifiers, but worth tightening for defensive style.

[atoomic]

@Koan-Bot rebase

[Koan-Bot]

Rebase: fix: preserve weakrefs in iterative clone path past MAX_DEPTH

Branch koan.atoomic/fix-iterative-weakref-loss rebased onto master and force-pushed.

Diff: 3 files changed, 133 insertions(+), 3 deletions(-)

Review feedback was analyzed and applied.

Changes

Compiles cleanly with no warnings.

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• Extracted repeated weakref-tracking pattern into CLONE_TRACK_WEAKREF(src, rv, weakrefs) macro (defined near other CLONE_* macros). Replaced all 5 identical if (SvWEAKREF(...)) av_push(weakrefs, SvREFCNT_inc_simple_NN(...)) blocks with a single macro call each, per reviewer request to factorize the boilerplate.

Actions

• Already-solved check: negative (confidence=high, reasoning=None of the recent master commits address weakref preservation in the iterative clone path; the clos)
• Resolved merge conflicts (1 round(s))
• Rebased koan.atoomic/fix-iterative-weakref-loss onto upstream/master
• Applied review feedback
• Pre-push CI check: previous run passed
• Force-pushed koan.atoomic/fix-iterative-weakref-loss to origin
• CI check enqueued in ## CI (async)

CI

CI will be checked asynchronously.

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Automated by Kōan

[atoomic]

@Koan-Bot rebase

[Koan-Bot]

Rebase: fix: preserve weakrefs in iterative clone path past MAX_DEPTH

Branch koan.atoomic/fix-iterative-weakref-loss rebased onto master and force-pushed.

Diff: 3 files changed, 133 insertions(+), 3 deletions(-)

Review feedback was analyzed and applied.

Actions

• Already-solved check: negative (confidence=high, reasoning=None of the recent master commits address weakref preservation in the iterative clone path — the clo)
• Resolved merge conflicts (1 round(s))
• Rebased koan.atoomic/fix-iterative-weakref-loss onto upstream/master
• Pre-push CI check: previous run passed
• Force-pushed koan.atoomic/fix-iterative-weakref-loss to origin
• CI check enqueued in ## CI (async)

CI

CI will be checked asynchronously.

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Automated by Kōan

[atoomic]

@Koan-Bot rr

[Koan-Bot]

PR Review — fix: preserve weakrefs in iterative clone path past MAX_DEPTH

Solid, well-scoped fix. The CLONE_TRACK_WEAKREF macro correctly mirrors the deferred-weakening pattern used by the recursive path (rv_clone / rv_clone_iterative). All five insertion points target the right source SVs (current_ref in the iterative walker, ref in sv_clone), and the SvREFCNT_inc_simple_NN before av_push matches the ownership contract expected by the end-of-clone weakening loop. C89 compliance is maintained — the chain_rv case is wrapped in its own block, and the other declarations sit at block tops. The test file covers both the deep iterative zone and the sv_clone MAX_DEPTH boundary, with proper strong anchors to avoid false negatives from freed referents. The two suggestions above are non-blocking. Merge-ready.

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🟢 Suggestions

1. Macro missing parentheses around parameter uses (`Clone.xs`, L44-49)

The CLONE_TRACK_WEAKREF macro parameters src, rv, and weakrefs are not parenthesized at their use sites inside the macro body. While current call sites always pass simple identifiers (so this is safe today), defensive macro style wraps each parameter in parentheses to prevent surprises if a complex expression is ever passed. Consider: if (SvWEAKREF((src))) av_push((weakrefs), SvREFCNT_inc_simple_NN((rv)));

#define CLONE_TRACK_WEAKREF(src, rv, weakrefs)				\
do {									\
    if (SvWEAKREF(src))							\
        av_push(weakrefs, SvREFCNT_inc_simple_NN(rv));			\
} while (0)

2. Comment says ~1250 but value depends on platform (`t/24-weakref-iterative.t`, L30)

$weak_level = int($deep_target / 4) yields 1250 on non-Windows but 625 on Windows/Cygwin (where $deep_target is 2500). The inline comment says "~1250" which is only true for one branch. Minor readability nit — consider making the comment dynamic or removing the absolute number.

my $weak_level = int($deep_target / 4);  # ~1250 — well within iterative zone

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Checklist

• No hardcoded secrets
• C89 compatibility (no C99 declarations after statements)
• Macro hygiene (do/while(0) wrapper)
• Refcount correctness (inc before av_push)
• Test coverage for new code paths
• MANIFEST updated
• No resource leaks in error paths

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Summary

Solid, well-scoped fix. The CLONE_TRACK_WEAKREF macro correctly mirrors the deferred-weakening pattern used by the recursive path (rv_clone / rv_clone_iterative). All five insertion points target the right source SVs (current_ref in the iterative walker, ref in sv_clone), and the SvREFCNT_inc_simple_NN before av_push matches the ownership contract expected by the end-of-clone weakening loop. C89 compliance is maintained — the chain_rv case is wrapped in its own block, and the other declarations sit at block tops. The test file covers both the deep iterative zone and the sv_clone MAX_DEPTH boundary, with proper strong anchors to avoid false negatives from freed referents. The two suggestions above are non-blocking. Merge-ready.

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Automated review by Kōan1a57708
4a59f59

[Koan-Bot]

Rebase with requested adjustments

Branch koan.atoomic/fix-iterative-weakref-loss was rebased onto master and review feedback was applied.

Changes applied

• Parenthesized all macro parameter uses in CLONE_TRACK_WEAKREF — wrapped src, rv, and weakrefs in parentheses at their use sites inside the macro body. This is defensive C macro style that prevents operator-precedence surprises if a caller ever passes an expression rather than a simple identifier, per the reviewer's suggestion about missing parenthesization.

Stats

22 files changed, 1806 insertions(+), 171 deletions(-)

Actions performed

• Already-solved check: negative (confidence=high, reasoning=The rv_clone_iterative path preserves SvWEAKREF (line 371), but av_clone_iterative's chain-walking l)
• Rebased koan.atoomic/fix-iterative-weakref-loss onto origin/master
• Applied review feedback
• Pre-push CI check: previous run passed
• Force-pushed koan.atoomic/fix-iterative-weakref-loss to origin
• CI check enqueued in ## CI (async)

CI status

CI will be checked asynchronously.

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Automated by Kōan