s2geometry v0.13.1 requires abseil LTS 2025.01.27+ due to absl::byteswap and absl::endian usage

[yharby]

Problem

The file src/s2/util/endian/endian.h in s2geometry v0.13.1 uses:

• absl::byteswap() (lines 28-29)
• absl::endian::native and absl::endian::little (lines 57, 114-118)

These APIs were only added in abseil LTS 2025.01.27. When building with older abseil versions (which many package managers and CI systems still provide), compilation fails with:

error: 'byteswap' is not a member of 'absl'
error: 'absl::endian' has not been declared

Environment

• s2geometry version: v0.13.1
• abseil version: older than LTS 2025.01.27 (e.g., versions provided by vcpkg in DuckDB extension CI)
• Build system: CMake with vcpkg

Reproduction

Build s2geometry v0.13.1 with an abseil version older than LTS 2025.01.27.

Suggested Fix

Add fallback implementations for older abseil versions using compiler intrinsics (__builtin_bswap16/32/64 for GCC/Clang) and compile-time endianness detection via __BYTE_ORDER__ macros.

This would maintain backwards compatibility with older abseil versions while still working with newer ones.

Related

This issue was discovered while upgrading s2geometry in the duckdb-geography extension.

[jmr]

Actually, we only guarantee 20250814. You can try 2025.01.27, but I think something else may be missing.

https://github.com/google/s2geometry/?tab=readme-ov-file#requirements-for-end-users-using-cmake

abseil version: older than LTS 2025.01.27 (e.g., versions provided by vcpkg in DuckDB extension CI)

vcpkg has 20250814, why don't you want to use it?

https://vcpkg.io/en/package/abseil

[yharby]

The DuckDB extension CI uses a vcpkg setup with an older abseil version. I've opened an issue on their side to upgrade it (duckdb/extension-ci-tools#294). If they can upgrade, the PR #491 may not be needed.

[jmr]

The DuckDB extension CI uses a vcpkg setup with an older abseil version. I've opened an issue on their side to upgrade it (duckdb/extension-ci-tools#294). If they can upgrade, the PR #491 may not be needed.

It looks like you were able to workaround on your side anyway.

Any idea when someone might reply to duckdb/extension-ci-tools#294?

[jmr]

I've opened an issue on their side to upgrade it (duckdb/extension-ci-tools#294).

There's no answer here and I don't see where abseil is used in duckdb/extension-ci-tools. Where is the old version referenced?