#!/bin/sh

# Build the cheap checks (crates/flow-checks, #96) as a WASI module and keep

# it at .flow/checks.wasm, where the pipeline's WASM jobs run it from.

#

#   scripts/checks-wasm.sh          rebuild .flow/checks.wasm

#   scripts/checks-wasm.sh --check  fail unless .flow/checks.wasm is what

#                                   the source builds (the fmt job runs this)

#

# The build is the same on any machine with the same toolchain (the build

# image's, images/rust): the crate is std only, the workspace path is

# remapped to /src and rust-src's to /rustc/COMMIT, and the module carries

# no debug info.

# Needs: rustup target wasm32-wasip1.

set -eu

cd "$(dirname "$0")/.."

target=$(mktemp -d)

trap 'rm -rf "$target"' EXIT

# Where rust-src is installed, the standard library's panic locations name

# it; map it to /rustc/COMMIT, as a toolchain without rust-src has them.

src="$(rustc --print sysroot)/lib/rustlib/src/rust"

commit=$(rustc -vV | sed -n 's/^commit-hash: //p')

RUSTFLAGS="--remap-path-prefix=$(pwd)=/src --remap-path-prefix=$src=/rustc/$commit" \

CARGO_PROFILE_RELEASE_DEBUG=0 CARGO_PROFILE_RELEASE_STRIP=true CARGO_INCREMENTAL=0 \

    cargo build -q --release --locked --target wasm32-wasip1 -p flow-checks --target-dir "$target"

built="$target/wasm32-wasip1/release/flow-checks.wasm"

if [ "${1:-}" = --check ]; then

    if cmp -s "$built" .flow/checks.wasm; then

        echo ".flow/checks.wasm is what crates/flow-checks builds ($(rustc --version))"

    else

        echo ".flow/checks.wasm differs from what crates/flow-checks builds: run scripts/checks-wasm.sh and commit it" >&2

        exit 1

    fi

else

    cp "$built" .flow/checks.wasm

    echo "built .flow/checks.wasm ($(wc -c < .flow/checks.wasm) bytes, $(rustc --version))"

fi