fix: resolve static linking failures with OpenSSL and duplicate symbols

[dkropachev]

Summary

Fix the static-linking regressions behind #164 at the installed-package boundary, not just for the in-tree integration binary. The branch now publishes the static driver's transitive link requirements through pkg-config, teaches the package smoke app to consume that metadata safely, removes duplicate testing stubs from the C++ side, and keeps the package CI coverage readable with dedicated static-smoke targets.

Fixes: #164

What Changed

1. Support installed static consumers and package checks

• publish transitive static-link dependencies in scylla-cpp-driver_static.pc
• resolve static pkg-config compile/link flags in the smoke app, including Apple framework flags
• keep the Windows external OpenSSL path explicit when the static integration build falls back to the vendored project
• align the package/static-integration checks with the installed artifacts rather than only the in-tree target

2. Remove duplicate static-integration stubs

• drop the C++ stubs from src/testing_unimplemented.cpp that are already provided by the Rust integration layer during cpp_integration_testing

3. Fix Windows OPENSSL_LIBS assembly

• build OPENSSL_LIBS with an explicit join so openssl-sys receives real library names in package and static-integration builds

4. Split static package smoke checks into dedicated CI targets

• add dedicated make targets for static smoke builds/runs
• call those targets directly from the package workflow instead of threading SCYLLA_SMOKE_BUILD_STATIC=ON through CI YAML

Commit Structure

• c1eeee8 static linking: support installed consumers and package checks
• 61d6d5f testing: remove duplicate static-integration stubs
• 1dd2538 windows: assemble OPENSSL_LIBS from discovered libraries
• 08cec82 ci: split static package smoke checks into dedicated targets
• 5f4f201 gitignore: ignore build_static

Testing

• cmake -S . -B /tmp/cpp-rs-driver-cmake-check -G Ninja -DCMAKE_BUILD_TYPE=Release
• make check
• make run-test-unit
• cmake -S . -B /tmp/cpp-rs-driver-install-build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/cpp-rs-driver-install-prefix && cmake --build /tmp/cpp-rs-driver-install-build -j 4 && cmake --install /tmp/cpp-rs-driver-install-build
• PKG_CONFIG_PATH=/tmp/cpp-rs-driver-install-prefix/lib/pkgconfig:/usr/lib/x86_64-linux-gnu/pkgconfig:/usr/share/pkgconfig cmake -S packaging/smoke-test-app -B /tmp/cpp-rs-driver-smoke-build -G Ninja -DCMAKE_BUILD_TYPE=Release -DSCYLLA_SMOKE_BUILD_STATIC=ON && PKG_CONFIG_PATH=/tmp/cpp-rs-driver-install-prefix/lib/pkgconfig:/usr/lib/x86_64-linux-gnu/pkgconfig:/usr/share/pkgconfig cmake --build /tmp/cpp-rs-driver-smoke-build -j 4
• cmake --build build_static -j 4 --target cassandra-integration-tests
• make -n OS=Windows_NT build-driver CMAKE_BUILD_TYPE=Release | rg "OPENSSL_LIBS|Join\(':', @\("
• make -n OS=Windows_NT build-static-integration-test-bin | rg "OPENSSL_LIBS|Join\(':', @\("
• make -n test-package-deb-static-smoke
• make -n test-package-rpm-native-static-smoke SCYLLA_HOST=scylla SKIP_DOCKER_COMPOSE=1
• make -n test-package-macos-static-smoke

Pre-review checklist

• I have split my patch into logically separate commits.
• All commit messages clearly explain what they change and why.
• PR description sums up the changes and reasons why they should be introduced.
• I have implemented Rust unit tests for the features/changes introduced.
• I have enabled appropriate tests in Makefile in {SCYLLA,CASSANDRA}_(NO_VALGRIND_)TEST_FILTER.
• I added appropriate Fixes: annotations to PR description.

[dkropachev]

I am not sure if I took correct way regarding Duplicate symbol guards.

[wprzytula]

I am not sure if I took correct way regarding Duplicate symbol guards.

No, it's not correct. The real problem in the first place is is that they are duplicated in the sources. I think a proper solution is to delete them from the testing_unimplemented.cpp. This will resolve the linking issues.

Optionally, we could make the stubs present in integration.rs print an error message and call sysexit. Unfortunately, throwing C++ exceptions is not possible from pure Rust with C FFI. @Lorak-mmk Should we bother with this?

[Lorak-mmk]

No, it's not correct. The real problem in the first place is is that they are duplicated in the sources. I think a proper solution is to delete them from the testing_unimplemented.cpp. This will resolve the linking issues.

Agreed.

@Lorak-mmk Should we bother with this?

Do we need to? Can't we use the stubs from integration.rs?

[wprzytula]

@Lorak-mmk Should we bother with this?

Do we need to? Can't we use the stubs from integration.rs?

I do propose using stubs from integration.rs. Additionally, I say that optionally we can make them call sysexit. Currently, they are just no-ops. The stubs in testing_unimplemented.cpp have a nice feature of throwing an exception, which fails nonsupported tests with a meaningful message.
But perhaps it's not important at all that nonsupported tests throw such exception / end in a distinctive way. I think so. Let's not bother.

[Lorak-mmk]

Sysexit or other abort method sounds reasonable.

[dkropachev]

Guys, could you please tell me what to do with the pr

[Lorak-mmk]

Section "Fix: Duplicate symbol guards (src/testing_unimplemented.cpp)" should be reverted. The correct fix is to remove those symbols from testing_unimplemented.cpp

[wprzytula]

Please improve commit messages. I can't read them.

[wprzytula]

❓ Why are you adding SCYLLA_SMOKE_BUILD_STATIC=ON everywhere?

[dkropachev]

My bad, removed it

[wprzytula]

commit Keep Windows package builds from exporting a literal OpenSSL variable name: commit message is not readable. Also, it contains magic formulas like Rejected: etc. Please write the commit message suitable for human reviewers.

[dkropachev]

updated