Problem

The Rust toolchain () references a system-installed WASI SDK linker:

--codegen=link-arg=-fuse-ld=/usr/local/wasi-sdk/bin/ld64.lld

Discovered in: @@rules_rust+//util/process_wrapper:process_wrapper

Discovery

Comprehensive hermiticity test revealed:

./tools/hermetic_test/comprehensive_test.sh
# Found in //examples/basic:hello_component

Impact

• Build depends on system WASI SDK installation
• Affects all Rust WASM targets
• Not hermetic for users of these rules

Root Cause

rules_rust is picking up system linker flags, possibly from:

1. Environment variables (RUSTFLAGS, CARGO_BUILD_TARGET_*_LINKER)
2. System rustc configuration
3. Default cc toolchain configuration

Investigation Needed

• Determine where rules_rust gets these linker flags
• Configure Rust toolchain to use hermetic WASI SDK from Bazel
• Ensure environment isolation in rules_rust actions

Related

• Non-hermetic linker reference in Go toolchain #162 (Fixed): Go toolchain had similar issue, fixed with pure = "on"