//! Tangle the canonical native fn registry from

//! =doc/scripting/native_reference.org= into

//! `src/natives/generated_specs.rs`. The org file is the source of

//! truth — this script is the build-time bridge cargo invokes

//! before compiling the crate.

//!

//! Mirrors the `scripting/format/build.rs` precedent: `emacs

//! --batch` evaluates the named babel block, which writes the Rust

//! file at a fixed path. `cargo build` is the only command needed;

//! editing the org and re-running `cargo build` regenerates the

//! tangled source (`cargo:rerun-if-changed=` on the org file

//! drives the incremental rebuild).

use std::path::Path;

use std::process::Command;

            "emacs --batch tangle of native_reference.org exited with {s} \

             — regen of rpc/src/natives/generated_specs.rs failed"

        ),

            "failed to spawn emacs for native_reference.org tangle: {e}. \

             cargo build requires emacs on PATH (same as finance/build.rs)"

        ),

    }

    // The babel block writes raw Rust without consulting rustfmt; run

    // rustfmt here so the file's whitespace matches the rest of the

    // tree. Without this, `cargo fmt --all --check` flags the tangled

    // file and the pre-commit hook refuses every commit.

/// Formats a generated source so it matches `cargo fmt --all --check`.

/// rustfmt is resolved from the active toolchain's sysroot (where

/// `cargo fmt` finds it), not bare `$PATH`: minimal CI images expose

/// rustfmt only in the sysroot bin, so `Command::new("rustfmt")` would

/// spawn-fail there and ship the file unformatted, breaking the later

/// fmt check. A genuine failure is surfaced as a build warning, not

/// silently swallowed.

    }

    // Probe the compiler Cargo set for this build (`$RUSTC`), not bare

    // `rustc`, so the sysroot matches the active toolchain.