#!/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