GH-45589: [C++] Enable singular test in Meson configuration

[WillAyd]

Rationale for this change

Adding this singular test helps us make incremental progress on Meson as a build system generator

What changes are included in this PR?

A single array-test for libarrow is being added

Are these changes tested?

Yes - see CI

Are there any user-facing changes?

No - this is only for developers

• GitHub Issue: [C++] Enable libarrow test in Meson configuration #45589

[github-actions]

⚠️ GitHub issue #45589 has been automatically assigned in GitHub to PR creator.

[WillAyd]

The static_library is required here because the Meson wrap dependency for gtest only provides consumers with the source files, and when using that in two different shared libraries then linking together you get an ODR violation.

See also mesonbuild/wrapdb#1937

[WillAyd]

This is to follow along with the CMake configuration. The option doesn't yet exist in Meson so I've hard-coded for now

[kou]

Suggested change

	meson setup \
	--prefix=${MESON_PREFIX:-${ARROW_HOME}} \
	--buildtype=${ARROW_BUILD_TYPE:-debug} \
	-Dtests=true \
	function meson_boolean() {
	if [ "${1}" = "ON" ]; then
	echo "true"
	else
	echo "false"
	fi
	}
	meson setup \
	--prefix=${MESON_PREFIX:-${ARROW_HOME}} \
	--buildtype=${ARROW_BUILD_TYPE:-debug} \
	-Dtests=$(meson_boolean ${ARROW_BUILD_TESTS:-OFF}) \

[kou]

Suggested change

	subprojects/*
	!subprojects/packagefiles
	!subprojects/*.wrap
	/subprojects/*
	!/subprojects/packagefiles
	!/subprojects/*.wrap

[kou]

@github-actions crossbow submit test-conda-cpp-meson

[github-actions]

Revision: 65779fa

Submitted crossbow builds: ursacomputing/crossbow @ actions-b0685743f1

Task	Status
test-conda-cpp-meson

[kou]

https://github.com/ursacomputing/crossbow/actions/runs/13468923214/job/37639840316#step:6:448

Run-time dependency rapidjson found: NO (tried pkgconfig and cmake)

Hmm. It's strange that RapidJSON wasn't found. RapidJSON exists in the environment:

https://github.com/ursacomputing/crossbow/actions/runs/13468923214/job/37639840316#step:6:351

rapidjson                 1.1.0.post20240409      hac33072_1    conda-forge

[WillAyd]

Sorry I've been away for a few days.

Hmm. It's strange that RapidJSON wasn't found. RapidJSON exists in the environment:

In spite of Meson not finding the system RapidJSON, it does still fall back to using the wrap file to download an appropriate copy. Seems like the error message from that run has to do with resolving the filepath to the bundled flatbuffers. Will investigate further

[WillAyd]

FWIW it might even be worthwhile to use Meson's wrap and subproject systems for flatbuffers instead of using a vendored copy. The limiting factor was that Arrow seems to statically assert the required major/minor version of flatbuffers, and the minor version requested does not exist in the wrapdb.

If there is some flexibility on that version check we could go down that path

[kou]

We should add support for system Flatbuffers, right? (We can fallback to the vendored Flatbuffers and generated files when system Flatbuffers don't exist.)

Could you open an issue for this? Let's discuss this in the new issue.