Build fails on libstdc++/GCC (e.g. Raspberry Pi aarch64): std::setw/setfill used without #include <iomanip>

[nitishagar]

Summary

cactus build --python fails to compile the native engine on libstdc++ (e.g. Raspberry Pi) because cactus-engine/src/telemetry_impl.cpp uses std::setw / std::setfill without including <iomanip>. The same latent defect exists in 14 other translation units that currently compile only via a transitive include.

Environment

• Board: Raspberry Pi (aarch64-linux-gnu)
• Toolchain: GCC 12.2.0 (Debian 12.2.0-14+deb12u1), libstdc++, glibc 2.36 (Debian 12 bookworm)
• Tree: upstream cactus main @ c90a1afa

Error

cactus-engine/src/telemetry_impl.cpp:689:24: error: 'setw' is not a member of 'std'
  689 |     oss << "-" << std::setw(4) << ((a >> 16) & 0xffffULL);
      |                        ^~~~
... repeats for each std::setw / std::setfill use (lines 666-671 and 687-692)
make[2]: *** [CMakeFiles/cactus_engine.dir/build.make:228: CMakeFiles/cactus_engine.dir/src/telemetry_impl.cpp.o] Error 1
Building Cactus for Python... Build failed

Root cause

telemetry_impl.cpp uses std::hex / std::setfill / std::setw (lines 666-671, 687-692) but does not include <iomanip>, and none of its headers pulls it in transitively — it does not include utils.h, the project header that provides <iomanip> elsewhere in the engine. On libc++ (macOS/clang) the symbols are reachable through other standard headers, so macOS CI passed; on libstdc++ (Pi GCC 12.2, aarch64) they are not, and the build breaks.

Scope

• Actually broken (reported failure): cactus-engine/src/telemetry_impl.cpp — no transitive <iomanip> path.
• Latent (compile today only via a transitive include from utils.h / test_utils.h): cactus-engine/src/complete.cpp plus 13 test TUs (cactus-engine/tests/*, cactus-kernels/tests/*, cactus-graph/tests/test_nn.cpp). Same non-portable reliance.
• Both telemetry_impl.cpp and complete.cpp are compiled into the cactus_engine static-lib target (cactus-engine/CMakeLists.txt, ENGINE_SOURCES).

Reproduction (on the failing toolchain)

#include <sstream>
int main(){ std::ostringstream o; o << std::setw(8) << 42u; }

g++ -std=c++20 repro.cpp → error: 'setw' is not a member of 'std'. Adding #include <iomanip> compiles clean. Verified on the Pi's GCC 12.2.0 / libstdc++ / aarch64.

Proposed fix

Add a direct #include <iomanip> to each affected translation unit. See #782.

[nitishagar]

Opened PR #782 with the fix — adds a direct #include <iomanip> to telemetry_impl.cpp (the actual failure) and to the other 14 translation units that rely on a transitive include. Reproduced the error and verified the fix on the reported toolchain (Raspberry Pi, GCC 12.2.0 / libstdc++ / aarch64).