Fix copy/move recursing into source through a symlinked destination ancestor#1073
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RyanZim merged 1 commit intoJun 29, 2026
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checkParentPaths walks up the destination's ancestors to detect when the destination is inside the source (which would cause copy to recurse into the tree it is creating). When an intermediate parent did not exist yet it returned early on ENOENT, so a deeper ancestor that is a symlink into the source tree was never checked. copy then created the missing path under the symlink target and walked into the subtree until ENAMETOOLONG. Recurse to the next parent on ENOENT instead of returning, so the self-subdirectory check keeps walking up to an existing ancestor.
JPeer264
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Jun 15, 2026
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Implementation and tests look fine, but I'm not the best to judge.
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Also thanks a lot for taking your time to fix it |
RyanZim
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Fixes #1071.
checkParentPathswalks up the destination's ancestors to catch the case where the destination is actually inside the source, which otherwise makescopyrecurse into the very tree it is creating. When an intermediate destination parent doesn't exist yet, it returned early onENOENTand stopped checking. If a deeper ancestor is a symlink into the source tree, that early return bypasses the check entirely.The result is that
copy(src, link/sub/dest)(wherelink->srcandlink/subdoesn't exist yet) keeps copyingsrcinto itself, growingsrc/sub/dest/sub/dest/...until it dies withENAMETOOLONG, instead of raising the usual "Cannot copy to a subdirectory of itself" error.Per @RyanZim's suggestion in the issue, the fix recurses to the next parent on
ENOENTinstead of returning, so the check keeps walking up until it reaches an existing ancestor (or the source parent / root). This affectscopy,copySync,move, andmoveSyncsince they all go throughcheckParentPaths.Testing
copyandcopySynccovering a non-existent dest parent under a symlink-into-src ancestor (fail before this change: async times out from the runaway recursion, sync doesn't throw; both pass after).npm test(lint + 728 unit + ESM).