#!/usr/bin/env bash
# CI check: clawhdf5-format has no truncating `u64 as usize` cast on a 32-bit
# target. HDF5 addresses and lengths are 64-bit; on wasm32 (or any 32-bit
# target) such a cast silently wraps an address past 4 GiB onto another part
# of the file. File values go through `addr::to_usize` (a clean error) and
# in-memory counts through `addr::saturating_usize`.
#
# Lints with clippy's cast_possible_truncation and fails on any u64 -> usize
# finding (other truncations are not checked here), once per feature set
# below. Together the sets compile every feature-gated line of the crate that
# ci-test.sh builds: features only add code, except `not(feature = ...)`
# paths for std/checksum/fast-checksum/szip, which the no-default-features
# and default sets cover. szip is left out (it needs libaec), as in
# ci-test.sh.
#
# The sets are linted for wasm32 where they build there. zstd links a C
# library that does not build for wasm32, so the set with it is linted for
# the host: the lint reports u64 -> usize casts whatever the target's
# pointer width, and the crate has no pointer-width-dependent code.
#
# Usage:
#   ./scripts/check-32bit-casts.sh
#
# Prerequisites:
#   rustup target add wasm32-unknown-unknown

set -euo pipefail

WASM="wasm32-unknown-unknown"
ALL_BUT_ZSTD="parallel,lz4,pcodec,fast-checksum,blake3_hash,plugin-filters,lookup-stats"

# target|cargo feature arguments
SETS=(
    "$WASM|--no-default-features"
    "$WASM|--no-default-features --features std,checksum"
    "$WASM|"
    "$WASM|--features $ALL_BUT_ZSTD"
    "host|--features $ALL_BUT_ZSTD,zstd"
)

status=0
for set in "${SETS[@]}"; do
    target=${set%%|*}
    args=${set#*|}
    target_args=()
    if [ "$target" != host ]; then
        target_args=(--target "$target")
    fi
    echo "==> Checking for truncating u64 -> usize casts in clawhdf5-format ($target: ${args:-default features})"
    # shellcheck disable=SC2086 # $args is a list of arguments
    out=$(cargo clippy -p clawhdf5-format "${target_args[@]}" $args \
        --message-format short \
        -- -A clippy::all -W clippy::cast_possible_truncation 2>&1) || {
        echo "$out"
        echo "==> clippy failed" >&2
        exit 1
    }
    found=$(grep -F 'casting `u64` to `usize`' <<<"$out" || true)
    if [ -n "$found" ]; then
        echo "$found"
        status=1
    fi
done
if [ "$status" -ne 0 ]; then
    echo "==> use addr::to_usize (file values) or addr::saturating_usize (in-memory counts)" >&2
    exit 1
fi
echo "==> no truncating u64 -> usize casts"