Convert EnsureCaseSensitiveDirectoryRecursive to iterative traversal#40347
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Convert EnsureCaseSensitiveDirectoryRecursive to iterative traversal#40347benhillis wants to merge 2 commits into
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Pull request overview
Converts EnsureCaseSensitiveDirectoryRecursive in filesystem.cpp from recursive DFS to an iterative traversal to prevent stack overflows in the WSL service during deep directory upgrades (e.g., during distro import).
Changes:
- Replace recursive depth-first traversal with an explicit stack-based traversal.
- Preserve bottom-up (children-before-parent) case-sensitivity marking and existing retry semantics.
Replace unbounded recursive depth-first traversal with an iterative approach using an explicit stack. A deeply nested directory tree could overflow the thread stack during the recursive calls. The iterative version collects directories in reverse post-order during traversal, then marks them bottom-up (children before parents), preserving the ordering invariant that EnsureCaseSensitiveDirectory relies on for its early-exit optimization. Bug: 61964147, 61974992, 61911308, 61463090 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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The original recursive EnsureCaseSensitiveDirectoryRecursive could blow the Windows 1 MB thread stack at a few hundred levels of nesting because each frame carried a FILE_ID_BOTH_DIR_INFORMATION enumeration buffer. The iterative implementation in this PR moves that state to the heap, so a very deep tree must complete without crashing. The test creates a 1024-level chain via the \\\\?\\ long-path prefix (cumulative path length exceeds MAX_PATH) and then calls EnsureCaseSensitiveDirectory on the root. Cleanup goes through the same long-path prefix so remove_all can see every component. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Summary
Converts
EnsureCaseSensitiveDirectoryRecursiveinfilesystem.cppfrom unbounded recursive depth-first traversal to an iterative approach using an explicit work stack.Problem
The recursive implementation of
EnsureCaseSensitiveDirectoryRecursivehas no depth limit — a deeply nested directory tree (e.g.node_modules) can exhaust the service thread stack.Fix
EnsureCaseSensitiveDirectory)wil::unique_hfilevector; raw handles used as non-owning references in work stacks