patches/0004: resolve NTFS symlink at readdir root before walkFileTree - #11
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Ilia (k15tfu)
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Files.walkFileTree(NOFOLLOW) treats an NTFS symbolic link to a directory
as a file: it calls visitFile on the link instead of preVisitDirectory,
so the children of the link target are never enumerated. The patched
WindowsFileSystem#readdir then returns a single Dirent for the link
itself, and any glob() over a package whose subdirectories are NTFS
symlinks (e.g. external/llvm++llvm_source+libcxx{,abi}, where src/,
include/, etc. are symlinks into llvm-raw) silently matches nothing
and trips --incompatible_disallow_empty_glob.
Resolve the link with toRealPath() unconditionally: readdir's contract
follows symlinks when resolving the directory itself regardless of
followSymlinks (which only governs entry types). Junctions are not
recognized as symlinks here and report isDirectory()==true natively,
so they're unaffected; the extra Files.isSymbolicLink() check is one
GetFileAttributes call per readdir.
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Ilia (k15tfu)
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| + } | ||
| + | ||
| + @Override | ||
| + public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) { |
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from https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html:
The visitFile method is invoked for all files, including directories, encountered at maxDepth, unless the basic file attributes cannot be read, in which case the visitFileFailed method is invoked.
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Files.walkFileTree(NOFOLLOW) treats an NTFS symbolic link to a directory as a file: it calls visitFile on the link instead of preVisitDirectory, so the children of the link target are never enumerated. The patched WindowsFileSystem#readdir then returns a single Dirent for the link itself, and any glob() over a package whose subdirectories are NTFS symlinks (e.g. external/llvm++llvm_source+libcxx{,abi}, where src/, include/, etc. are symlinks into llvm-raw) silently matches nothing and trips --incompatible_disallow_empty_glob.
Resolve the link with toRealPath() when called with NOFOLLOW. Junctions report isDirectory()==true under NOFOLLOW and are unaffected; the extra Files.isSymbolicLink() check is one GetFileAttributes call per readdir.