OpenSuse 16 Leap capnp issue

[maflcko]

Steps to reproduce:

zypper in -y zeromq-devel libevent-devel boost-devel sqlite3-devel qt6-base-devel qt6-tools-devel qt6-linguist-devel qrencode-devel find bison gcc-c++ libtool make autoconf automake python3 clang llvm libcapnp-devel capnproto patch xz curl wget htop git vim ccache && git clone https://github.com/bitcoin/bitcoin.git --depth=1 ./b-c && cd b-c && rm -rf ./bld-cmake && cmake -B ./bld-cmake -DCMAKE_C_COMPILER='clang' -DCMAKE_CXX_COMPILER='clang++' -DBUILD_GUI=ON -DBUILD_FUZZ_BINARY=ON -DBUILD_BENCH=ON -DWITH_ZMQ=ON -DBUILD_UTIL_CHAINSTATE=ON -DBUILD_KERNEL_LIB=ON && cmake --build ./bld-cmake --parallel $(nproc)

Failure:

-- Configuring done (0.5s)
-- Generating done (0.1s)
-- Build files have been written to: /root/b-c/build-cdash
Command exited with the value: 0
SetCTestConfiguration:BuildDirectory:/root/b-c/build-cdash
SetCTestConfiguration:SourceDirectory:/root/b-c
SetMakeCommand:/usr/bin/cmake --build . --config "Release"
SetCTestConfiguration:MakeCommand:/usr/bin/cmake --build . --config "Release"
Build project
MakeCommand:/usr/bin/cmake --build . --config "Release"
Run command: "/usr/bin/cmake" "--build" "." "--config" "Release"
[1/589] Compiling Cap'n Proto schema include/mp/proxy.capnp
FAILED: src/ipc/libmultiprocess/include/mp/proxy.capnp.c++ src/ipc/libmultiprocess/include/mp/proxy.capnp.h /root/b-c/build-cdash/src/ipc/libmultiprocess/include/mp/proxy.capnp.c++ /root/b-c/build-cdash/src/ipc/libmultiprocess/include/mp/proxy.capnp.h 
cd /root/b-c/build-cdash/src/ipc/libmultiprocess && //bin/capnp compile -o //bin/capnpc-c++:/root/b-c/build-cdash/src/ipc/libmultiprocess --src-prefix /root/b-c/src/ipc/libmultiprocess -I /root/b-c/src/ipc/libmultiprocess -I /lib64/cmake/CapnProto/../../../include /root/b-c/src/ipc/libmultiprocess/include/mp/proxy.capnp
//bin/capnp compile: -I /lib64/cmake/CapnProto/../../../include: no such directory
Try '//bin/capnp compile --help' for more information.

[maflcko]

cc @hebasto

[hebasto]

I can't reproduce the issue.

UPDATE. See #14 (comment).

[maflcko]

Hmm. I guess there are not Leap 16 container images yet, but I can still reproduce this on Hetzner. (cpx42 box)

zypper in -y zeromq-devel libevent-devel boost-devel sqlite3-devel qt6-base-devel qt6-tools-devel qt6-linguist-devel qrencode-devel find bison gcc-c++ libtool make autoconf automake python3 clang llvm libcapnp-devel capnproto patch xz curl wget htop git vim ccache && git clone https://github.com/bitcoin/bitcoin.git --depth=1 ./b-c && cd b-c && rm -rf ./bld-cmake && cmake -B ./bld-cmake -DCMAKE_C_COMPILER='clang' -DCMAKE_CXX_COMPILER='clang++' -DBUILD_GUI=ON -DBUILD_FUZZ_BINARY=ON -DBUILD_BENCH=ON -DWITH_ZMQ=ON -DBUILD_UTIL_CHAINSTATE=ON -DBUILD_KERNEL_LIB=ON && cmake --build ./bld-cmake --parallel 1

Configure summary
=================
Executables:
  bitcoin ............................. ON
  bitcoind ............................ ON
  bitcoin-node (multiprocess) ......... ON
  bitcoin-qt (GUI) .................... ON
  bitcoin-gui (GUI, multiprocess) ..... ON
  bitcoin-cli ......................... ON
  bitcoin-tx .......................... ON
  bitcoin-util ........................ ON
  bitcoin-wallet ...................... ON
  bitcoin-chainstate (experimental) ... ON
  libbitcoinkernel (experimental) ..... ON
  kernel-test (experimental) .......... ON
Optional features:
  wallet support ...................... ON
  external signer ..................... ON
  ZeroMQ .............................. ON
  IPC ................................. ON
  Embedded ASMap ...................... ON
  USDT tracing ........................ OFF
  QR code (GUI) ....................... ON
  DBus (GUI) .......................... ON
Tests:
  test_bitcoin ........................ ON
  test_bitcoin-qt ..................... ON
  bench_bitcoin ....................... ON
  fuzz binary ......................... ON

Cross compiling ....................... FALSE
C++ compiler .......................... Clang 19.1.7, /usr/bin/clang++
CMAKE_BUILD_TYPE ...................... RelWithDebInfo
Preprocessor defined macros ........... 
C++ compiler flags .................... -O2 -g -std=c++20 -fPIC -fmacro-prefix-map=/root/b-c/b-c/src=. -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -Wstack-protector -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wall -Wextra -Wgnu -Wcovered-switch-default -Wformat -Wformat-security -Wvla -Wshadow-field -Wthread-safety -Wloop-analysis -Wredundant-decls -Wunused-member-function -Wdate-time -Wconditional-uninitialized -Woverloaded-virtual -Wsuggest-override -Wimplicit-fallthrough -Wunreachable-code -Wdocumentation -Wself-assign -Wundef -Wno-unused-parameter
Linker flags .......................... -O2 -g -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wl,-z,relro -Wl,-z,now -Wl,-z,separate-code -fPIE -pie

NOTE: The summary above may not exactly match the final applied build flags
      if any additional CMAKE_* or environment variables have been modified.
      To see the exact flags applied, build with the --verbose option.

Treat compiler warnings as errors ..... OFF
Use ccache for compiling .............. ON


-- Configuring done (23.5s)
-- Generating done (0.2s)
-- Build files have been written to: /root/b-c/b-c/bld-cmake
[  0%] Building CXX object src/ipc/libmultiprocess/CMakeFiles/mputil.dir/src/mp/util.cpp.o
[  0%] Built target mputil
[  0%] Building CXX object src/ipc/libmultiprocess/CMakeFiles/mpgen.dir/src/mp/gen.cpp.o
[  0%] Linking CXX executable mpgen
[  0%] Built target mpgen
[  0%] Compiling Cap'n Proto schema include/mp/proxy.capnp
//bin/capnp compile: -I /lib64/cmake/CapnProto/../../../include: no such directory
Try '//bin/capnp compile --help' for more information.
gmake[2]: *** [src/ipc/libmultiprocess/CMakeFiles/multiprocess.dir/build.make:74: src/ipc/libmultiprocess/include/mp/proxy.capnp.c++] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1575: src/ipc/libmultiprocess/CMakeFiles/multiprocess.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2

[hebasto]

FWIW, here is what I have:

• OpenSUSE: Add new workflow hebasto/bitcoin-core-nightly#267
• https://github.com/hebasto/bitcoin-core-nightly/actions/runs/26686893975/job/78656556064

Still not able to reproduce the issue.

https://github.com/hebasto/bitcoin-core-nightly/actions/runs/26686893975/job/78656556064#step:8:394:

 [ 30%] Compiling Cap'n Proto schema include/mp/proxy.capnp

[maflcko]

Not sure why it doesn't reproduce in docker, but an LLM claims that this reproduces inside and outside of docker:

bash -lc 'tmp=$(mktemp -d); cat > "$tmp/repro.cmake" <<"EOF"
    cmake_minimum_required(VERSION 3.12)
    set(tmp_root "${CMAKE_CURRENT_LIST_DIR}/_tmp")
    file(MAKE_DIRECTORY "${tmp_root}")
    file(WRITE "${tmp_root}/CMakeLists.txt" [==[
    cmake_minimum_required(VERSION 3.12)
    project(repro)
    find_package(CapnProto REQUIRED NO_MODULE)
    capnp_generate_cpp(SRCS HDRS simple.capnp)
    add_custom_target(repro ALL DEPENDS ${SRCS} ${HDRS})
    ]==])
    file(WRITE "${tmp_root}/simple.capnp" "@0x9a4b6d1c7e2f3a11;\n\nstruct Foo {\n  x @0 :UInt64;\n}\n")
    execute_process(COMMAND "cmake" -S "${tmp_root}" -B "${tmp_root}/build" RESULT_VARIABLE cfg_result)
    if(NOT cfg_result EQUAL 0)
      message(FATAL_ERROR "configure failed: ${cfg_result}")
    endif()
    execute_process(COMMAND "cmake" --build "${tmp_root}/build" --target repro RESULT_VARIABLE build_result)
    if(NOT build_result EQUAL 0)
      message(FATAL_ERROR "build failed: ${build_result}")
    endif()
EOF
    cmake -P "$tmp/repro.cmake"'

[hebasto]

Hmm. I guess there are not Leap 16 container images yet, but I can still reproduce this on Hetzner. (cpx42 box)

Could be fixed with -DCMAKE_PREFIX_PATH=/usr.

[hebasto]

A simple fix for Libmultiprocess is possible for CMake >= 3.28. I'm not sure if it's worth the effort, considering that the project has clung to CMake 3.12 syntax.

[hebasto]

Here is a breakdown of the issue.

1. By default, the PATH environment variable affects CMake's find_package command behaviour:

Path entries ending in /bin or /sbin are automatically converted to their parent directories...

2. The root account on a Hetzner CPX42 box has:

# printenv PATH
/sbin:/usr/sbin:/usr/local/sbin:/root/bin:/usr/local/bin:/usr/bin:/bin

Note that /sbin precedes /usr/sbin. This results in CMake finding /lib64/cmake/CapnProto/../../../include instead of /usr/lib64/cmake/CapnProto/../../../include.

3. The capnp compiler resolves /lib64/cmake/CapnProto/../../../include lexically, ignoring the fact that /lib64 is a symlink to /usr/lib64, and consequently fails to find /include.

Here are possible workarounds:

1. Avoid using the root account.

2. Fix the PATH variable:

export PATH=/usr/sbin:/sbin:/usr/local/sbin:/root/bin:/usr/local/bin:/usr/bin:/bin

3. Configure with -DCMAKE_PREFIX_PATH=/usr.

4. Apply the following patch to ignore PATH during package resolution:

--- a/src/ipc/libmultiprocess/CMakeLists.txt
+++ b/src/ipc/libmultiprocess/CMakeLists.txt
@@ -13,7 +13,7 @@ endif()
 include("cmake/compat_find.cmake")
 
 find_package(Threads REQUIRED)
-find_package(CapnProto 0.7 QUIET NO_MODULE)
+find_package(CapnProto 0.7 QUIET NO_MODULE NO_SYSTEM_ENVIRONMENT_PATH)
  if(NOT CapnProto_FOUND)
    message(FATAL_ERROR
      "Cap'n Proto is required but was not found.\n"

[maflcko]

My llm bot said this, but I am not familiar with build-systems, so I don't really know if this is just ai slop:

• Two plausible Cap’n Proto-side patches:
  
  1. Narrow packaging fix in CMake/pkg-config
  This keeps consumer builds working by exporting a canonical include path instead of a symlink-derived one.
  
  In c++/cmake/CapnProtoConfig.cmake.in:41, canonicalize the include dir before exposing it:
  
  set(CAPNP_INCLUDE_DIRECTORY "@PACKAGE_CMAKE_INSTALL_FULL_INCLUDEDIR@")
  get_filename_component(CAPNP_INCLUDE_DIRECTORY "${CAPNP_INCLUDE_DIRECTORY}" REALPATH)
  
  Or, if you prefer file():
  
  set(CAPNP_INCLUDE_DIRECTORY "@PACKAGE_CMAKE_INSTALL_FULL_INCLUDEDIR@")
  file(REAL_PATH "${CAPNP_INCLUDE_DIRECTORY}" CAPNP_INCLUDE_DIRECTORY)
  
  Then do the same for the pkg-config side, so includedir doesn’t point at a path that later collapses badly through /lib64/.../../../../include.
  
  The idea is: consumers receive /usr/include, not /lib64/cmake/CapnProto/../../../include.
  




  2. Robust compiler fix in capnp itself
  This is the deeper fix: stop resolving import/include paths lexically in the compiler.
  
  The problematic code is in c++/src/capnp/compiler/capnp.c++:1925, where getSourceDirectory() currently does:
  
  auto cwd = disk->getCurrentPath();
  auto path = cwd.evalNative(pathStr);
  ...
  KJ_IF_SOME(dir, disk->getRoot().tryOpenSubdir(path)) {
  
  That lexical evalNative() step is what lets /lib64/.../../../../include collapse to /include before the filesystem can resolve /lib64 -> /usr/lib64.
  
  A better fix is to resolve the path physically, component by component, using the filesystem API rather than normalizing .. purely in string space. In sketch form:
  
  kj::Maybe<const kj::ReadableDirectory&> getSourceDirectory(
      kj::StringPtr pathStr, bool isSourcePrefix) {
    auto& root = disk->getRoot();

    // Resolve against the actual filesystem, not lexical path rules.
    KJ_IF_SOME(dir, resolvePathPhysically(root, pathStr)) {
      ...
      return dir;
    }
    return kj::none;
  }