Found in #35713. If a static class member is not inlined or constexpr, the linker will fail when attempting to ODR-use the constant (passing as const T&). These can be fixed by finding all member variables that are const qualified and inlining them with constexpr. There is a clang-tidy pull request that would lint these callsites: https://github.com/llvm/llvm-project/pull/162741
A script was used to modify these sites, however it cannot run as a scripted-diff because it uses clang-query and a build folder.
The script only queries for integer and enumeration types, as other data members would have to be marked constexpr or inline from what I understand: https://en.cppreference.com/cpp/language/static#Constant_static_members
Removing the ZMQ forward declaration was a clang-tidy lint.
<details> <summary>The script used to find these sites, LLM assisted:</summary>
set -uxo pipefail
cd "$(git rev-parse --show-toplevel)"
BUILD=${BUILD:-build}
if [ ! -f "${BUILD}/compile_commands.json" ]; then
echo "error: ${BUILD}/compile_commands.json not found. Run cmake -B ${BUILD} first." >&2
exit 1
fi
if ! command -v clang-query >/dev/null; then
echo "error: clang-query not on PATH. Install clang-tools." >&2
exit 1
fi
if ! git diff --quiet || ! git diff --cached --quiet; then
echo "error: working tree has uncommitted changes. Commit or stash first." >&2
exit 1
fi
MATCHER='match varDecl(hasParent(cxxRecordDecl()),
hasType(qualType(isConstQualified(),
anyOf(hasCanonicalType(isInteger()),
hasDeclaration(enumDecl())))),
hasInitializer(expr()),
unless(isConstexpr()),
isExpansionInFileMatching("/src/"))'
RAW=$(mktemp)
trap 'rm -f "$RAW"' EXIT
echo "Sweeping TUs (batched, may take a few minutes)..." >&2
find src -type d \( -name secp256k1 -o -name leveldb -o -name crc32c \
-o -name minisketch -o -name libmultiprocess -o -name ctaes \) -prune -o \
-name '*.cpp' -print0 \
| xargs -0 -n 50 clang-query -p "${BUILD}" \
-c 'set output diag' \
-c "${MATCHER}" \
>>"$RAW" || true
ROOT=$(pwd)
LOCS=$(grep -oE "${ROOT}/src/[^:]+:[0-9]+:[0-9]+:" "$RAW" \
| sed -E "s|^${ROOT}/||; s|:[0-9]+:$||" \
| sort -u)
if [ -z "$LOCS" ]; then
echo "no matches" >&2
exit 0
fi
FILTERED=""
while IFS=: read -r file line; do
case "$file" in
src/secp256k1/*|src/leveldb/*|src/crc32c/*|src/minisketch/*|src/ipc/libmultiprocess/*|src/crypto/ctaes/*) continue ;;
src/tinyformat.h) continue ;;
esac
src=$(sed -n "${line}p" "$file")
case "$src" in *inline*) continue ;; esac
FILTERED+="${file}:${line}"$'\n'
done <<<"$LOCS"
FILTERED=$(printf '%s' "$FILTERED" | sed '/^$/d')
if [ -z "$FILTERED" ]; then
echo "no matches after filtering" >&2
exit 0
fi
echo "Sites to rewrite ($(echo "$FILTERED" | wc -l)):" >&2
echo "$FILTERED" >&2
declare -A LINES
while IFS=: read -r file line; do
LINES[$file]+="${line} "
done <<<"$FILTERED"
for file in "${!LINES[@]}"; do
args=()
for line in ${LINES[$file]}; do
args+=(-e "${line}s/static const /static constexpr /")
done
sed -i "${args[@]}" "$file"
done
echo >&2
echo "===== proposed diff =====" >&2
git --no-pager diff
</details>
