review: feature-gate and update maybe_exit_on_error documentation

Author: abrown

Cargo.toml

@@ -28,7 +28,7 @@ wasmtime-cli-flags = { workspace = true }
 wasmtime-cranelift = { workspace = true }
 wasmtime-environ = { workspace = true }
 wasmtime-wast = { workspace = true }
-wasmtime-wasi = { workspace = true }
+wasmtime-wasi = { workspace = true, features = ["exit"] }
 wasmtime-wasi-crypto = { workspace = true, optional = true }
 wasmtime-wasi-nn = { workspace = true, optional = true }
 wasmtime-wasi-threads = { workspace = true, optional = true }

crates/wasi-threads/Cargo.toml

@@ -17,7 +17,7 @@ log = { workspace = true }
 rand = "0.8"
 wasi-common = { workspace = true }
 wasmtime = { workspace = true }
-wasmtime-wasi = { workspace = true }
+wasmtime-wasi = { workspace = true, features = ["exit"] }
 
 [badges]
 maintenance = { status = "experimental" }

crates/wasi/Cargo.toml

@@ -25,3 +25,4 @@ anyhow = { workspace = true }
 default = ["sync"]
 sync = ["wasi-cap-std-sync"]
 tokio = ["wasi-tokio", "wasmtime/async", "wiggle/wasmtime_async"]
+exit = []

crates/wasi/src/lib.rs

@@ -87,8 +87,10 @@ pub mod snapshots {
 /// understands the error. If the error is not an `I32Exit` or `Trap`, return
 /// the error back to the caller for it to decide what to do.
 ///
-/// Note: this function is designed for CLI usage of Wasmtime; embedders of
-/// Wasmtime may want different error handling.
+/// Note: this function is designed for usage where it is acceptable for
+/// Wasmtime failures to terminate the parent process, such as in the Wasmtime
+/// CLI; this would not be suitable for use in multi-tenant embeddings.
+#[cfg(feature = "exit")]
 pub fn maybe_exit_on_error(e: anyhow::Error) -> anyhow::Error {
     use std::process;
     use wasmtime::Trap;