std: Slightly more robust env var handling #29305
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r? @brson (rust_highfive has picked a reviewer for you, use r? to override) |
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It would probably be nicer to include either the error code or the offending key, rather than just a static message. |
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Also, do we want to treat invalid key as missing? Should we also treat File::open("\0") as file not found? |
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Hm that's true about treating an invalid key, I'll switch it back to being a panic. |
alexcrichton
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As discovered in rust-lang#29298, `env::set_var("", "")` will panic, but it turns out that it *also* deadlocks on Unix systems. This happens because if a panic happens while holding the environment lock, we then go try to read RUST_BACKTRACE, grabbing the environment lock, causing a deadlock. Specifically, the changes made here are: * The environment lock is pushed into `std::sys` instead of `std::env`. This also only puts it in the Unix implementation, not Windows where the functions are already threadsafe. * The `std::sys` implementation now returns `io::Result` so panics are explicitly at the `std::env` level. The panic messages have also been improved in these situations.
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ping r? @brson |
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@bors r+ |
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📌 Commit 4b43e07 has been approved by |
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As discovered in #29298, `env::set_var("", "")` will panic, but it turns out that it *also* deadlocks on Unix systems. This happens because if a panic happens while holding the environment lock, we then go try to read RUST_BACKTRACE, grabbing the environment lock, causing a deadlock. Specifically, the changes made here are: * The environment lock is pushed into `std::sys` instead of `std::env`. This also only puts it in the Unix implementation, not Windows where the functions are already threadsafe. * The `std::sys` implementation now returns `io::Result` so panics are explicitly at the `std::env` level.
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As discovered in #29298,
env::set_var("", "")will panic, but it turns outthat it also deadlocks on Unix systems. This happens because if a panic
happens while holding the environment lock, we then go try to read
RUST_BACKTRACE, grabbing the environment lock, causing a deadlock.
Specifically, the changes made here are:
std::sysinstead ofstd::env. Thisalso only puts it in the Unix implementation, not Windows where the functions
are already threadsafe.
std::sysimplementation now returnsio::Resultso panics areexplicitly at the
std::envlevel.