bootstrap/clean.rs cannot handle symlinks #40860
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T-bootstrap
Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap)
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alexcrichton
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I was able to reproduce this on my setup with: export MYARCH=x86_64-apple-darwin && mkdir -p build/$MYARCH/subdir && touch build/$MYARCH/subdir/file && ln -s build/$MYARCH/subdir/file build/$MYARCH/subdir/symlink |
frewsxcv
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Apr 6, 2017
Handle symlinks in src/bootstrap/clean.rs (mostly) -- resolves rust-lang#40860. In response to rust-lang#40860 The broken condition can be replicated with: ```shell export MYARCH=x86_64-apple-darwin && mkdir -p build/$MYARCH/subdir && touch build/$MYARCH/subdir/file && ln -s build/$MYARCH/subdir/file build/$MYARCH/subdir/symlink ``` `src/bootstrap/clean.rs` has a custom implementation of removing a tree `fn rm_rf` that used `std::path::Path::{is_file, is_dir, exists}` while recursively deleting directories and files. Unfortunately, `Path`'s implementation of `is_file()` and `is_dir()` and `exists()` always unconditionally follow symlinks, which is the exact opposite of standard implementations of deleting file trees. It appears that this custom implementation is being used to workaround a behavior in Windows where the files often get marked as read-only, which prevents us from simply using something nice and simple like `std::fs::remove_dir_all`, which properly deletes links instead of following them. So it looks like the fix is to use `.symlink_metadata()` to figure out whether tree items are files/symlinks/directories. The one corner case this won't cover is if there is a broken symlink in the "root" `build/$MYARCH` directory, because those initial entries are run through `Path::canonicalize()`, which panics with broken symlinks. So lets just never use symlinks in that one directory. :-)
frewsxcv
added a commit
to frewsxcv/rust
that referenced
this issue
Apr 6, 2017
Handle symlinks in src/bootstrap/clean.rs (mostly) -- resolves rust-lang#40860. In response to rust-lang#40860 The broken condition can be replicated with: ```shell export MYARCH=x86_64-apple-darwin && mkdir -p build/$MYARCH/subdir && touch build/$MYARCH/subdir/file && ln -s build/$MYARCH/subdir/file build/$MYARCH/subdir/symlink ``` `src/bootstrap/clean.rs` has a custom implementation of removing a tree `fn rm_rf` that used `std::path::Path::{is_file, is_dir, exists}` while recursively deleting directories and files. Unfortunately, `Path`'s implementation of `is_file()` and `is_dir()` and `exists()` always unconditionally follow symlinks, which is the exact opposite of standard implementations of deleting file trees. It appears that this custom implementation is being used to workaround a behavior in Windows where the files often get marked as read-only, which prevents us from simply using something nice and simple like `std::fs::remove_dir_all`, which properly deletes links instead of following them. So it looks like the fix is to use `.symlink_metadata()` to figure out whether tree items are files/symlinks/directories. The one corner case this won't cover is if there is a broken symlink in the "root" `build/$MYARCH` directory, because those initial entries are run through `Path::canonicalize()`, which panics with broken symlinks. So lets just never use symlinks in that one directory. :-)
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The implementation can only handle regular files and directories:
Apparently the symlink was generated by
in
bootstrap/doc.rsThe text was updated successfully, but these errors were encountered: