feat: Node::free_subtree — immediate discard with wrapper neutralization - #210
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unlink_node alone never frees a doc-owned node, and set_rust_owned defers the free to the last wrapper drop — which a stray clone in a long-lived collection postpones past the owning document's xmlFreeDoc, turning the eventual xmlFreeNode into a use-after-free (observed: SIGSEGV in xmlDictOwns when a consumer's bookkeeping Vec dropped after the Document). free_subtree frees the C subtree NOW: it unlinks, walks the subtree iteratively (elements, texts, attributes), nulls the shared node_ptr of every registered wrapper (clones anywhere become inert no-ops) and clears the bookkeeping entries, then calls xmlFreeNode once. Documents and document fragments are refused. Driver: latexml-oxide's math parser discards thousands of replaced subtrees per document; without a true free they leak ~1.4 MB per formula. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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What. A discard operation that actually frees:
Node::free_subtreedetaches the node, walks its C subtree iteratively (elements, texts, attributes), nulls the sharednode_ptrof every registered wrapper (stray clones anywhere become inert no-ops) and clears the bookkeeping entries, then callsxmlFreeNodeonce. Documents/fragments are refused.Why.
unlink_nodealone never frees a doc-owned node, andset_rust_owneddefers the free to the last wrapper drop — which a clone parked in a long-lived collection postpones past the owning document'sxmlFreeDoc, turning the eventual free into a use-after-free (observed: SIGSEGV inxmlDictOwns). Driver: latexml-oxide's math parser discards thousands of replaced subtrees per document (~1.4 MB/formula leaked; 31.2M leaked allocations on a 2 MB slice, ~99% eliminated by this).Validation. New
tests/free_subtree_tests.rs(5 tests: held-wrapper neutralization incl. post-document-drop, detached and never-linked trees, double-free-via-clone no-op, document refusal); full fork suite green; release prep 0.3.17 included.🤖 Generated with Claude Code