Colin Murphy 2cde8d967a Fix std::fs::copy on WASI by setting proper OpenOptions flags ...

When PR #147572 switched WASI to use Unix-style filesystem APIs, the
open_to_and_set_permissions function for WASI was implemented to call
OpenOptions::new().open() without setting any access mode flags.

This causes std::fs::copy to fail with the error:
"must specify at least one of read, write, or append access"

The fix is to explicitly set .write(true), .create(true), and
.truncate(true) on the OpenOptions, matching the behavior of the
non-WASI Unix implementation but without the permission handling
that WASI doesn't support.

Minimal reproduction:
    fn main() {
        std::fs::write("/src.txt", b"test").unwrap();
        match std::fs::copy("/src.txt", "/dst.txt") {
            Ok(_) => println!("PASS: fs::copy works!"),
            Err(e) => println!("FAIL: {}", e),
        }
    }

    # Compile and run:
    rustc +nightly --target wasm32-wasip2 test.rs -o test.wasm
    wasmtime -S cli --dir . test.wasm

    # Before fix: FAIL: must specify at least one of read, write, or append access
    # After fix:  PASS: fs::copy works!

Note: The existing test library/std/src/fs/tests.rs::copy_file_ok
would have caught this regression if the std test suite ran on WASI
targets. Currently std tests don't compile for wasm32-wasip2 due to
Unix-specific test code in library/std/src/sys/fd/unix/tests.rs.

Fixes the regression introduced in nightly-2025-12-10.

2026-01-09 10:16:00 -05:00

..

benches

benchmark path.components() iteration

2025-10-25 14:46:58 +02:00

src

Fix std::fs::copy on WASI by setting proper OpenOptions flags

2026-01-09 10:16:00 -05:00

tests

add oneshot tests

2026-01-05 09:47:20 +11:00

build.rs

Update to new API, allowing to remove check_doc_cfg.rs file from librustdoc

2025-12-10 12:28:08 +01:00

Cargo.toml

std: switch to moto-rt v0.16.0

2025-12-19 15:48:47 -08:00