Arch Linux User Repository

Fixed in 2.6.0-2

I'm getting this :

CMake Error at libmamba/CMakeLists.txt:448 (find_package):
Could not find a package configuration file provided by "msgpack-c" with
any of the following names:

  msgpack-c.cps
  msgpack-cConfig.cmake
  msgpack-c-config.cmake

Add the installation prefix of "msgpack-c" to CMAKE_PREFIX_PATH or set
"msgpack-c_DIR" to a directory containing one of the above files.  If
"msgpack-c" provides a separate development package or SDK, be sure it has
been installed.

Thanks @sor for report this. I noticed upstream also detect the error, we will go patch soon or await two or three days they release a new version.

https://github.com/mamba-org/mamba/commit/f7d6d8e572bf3e8f7a9a3b7d45903f5377251106

I did not use this package before and wanted to install version 2.5.0-2 today, the compilation ran into errors in file specs.cpp on line 348 and 349. First error was this:

/home/sor/.cache/paru/clone/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp:348:48: error: conversion from ‘<unresolved overloaded function type>’ to ‘const pybind11::cpp_function’ is ambiguous
  348 |             .def_property_readonly("location", &UnresolvedChannel::location)
      |                                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/sor/.cache/paru/clone/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp:348:48: note: there are 2 candidates

second error:

/home/sor/pkg/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp: In function ‘void mambapy::bind_submodule_specs(pybind11::module_)’:
/home/sor/pkg/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp:349:56: error: conversion from ‘<unresolved overloaded function type>’ to ‘const pybind11::cpp_function’ is ambiguous
  349 |             .def_property_readonly("platform_filters", &UnresolvedChannel::platform_filters);
      |                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/sor/pkg/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp:349:56: note: there are 2 candidates

I fixed it with this patch:

--- /home/sor/pkg/micromamba/src/mamba-2.5.0/libmambapy/bindings/specs.cpp  2026-01-08 14:47:10.000000000 +0100
+++ /home/sor/pkg/specs.cpp 2026-04-21 11:33:46.875121866 +0200
@@ -345,8 +345,8 @@
             .def("__copy__", &copy<UnresolvedChannel>)
             .def("__deepcopy__", &deepcopy<UnresolvedChannel>, py::arg("memo"))
             .def_property_readonly("type", &UnresolvedChannel::type)
-            .def_property_readonly("location", &UnresolvedChannel::location)
-            .def_property_readonly("platform_filters", &UnresolvedChannel::platform_filters);
+            .def_property_readonly("location", static_cast<const std::string& (UnresolvedChannel::*)() const &>(&UnresolvedChannel::location))
+            .def_property_readonly("platform_filters", static_cast<const mamba::util::flat_set<std::string>& (UnresolvedChannel::*)() const &>(&UnresolvedChannel::platform_filters));

         py::class_<BasicHTTPAuthentication>(m, "BasicHTTPAuthentication")
             .def(

I don't know if it is optimal or even correct, but it compiled and the .py-file i wanted to run was also happy :D

For me the build failed on "libmamba/CMakeFiles/libmamba-dyn.dir/src/solver/problems_graph.cpp.o" with loads of errors when I had fmt9 installed, but after removing it (and keeping the "fmt" package) it worked fine

As per the previous comment, I get a failure to build as it cannot find a libmamba-spdlog library (note that this is actually a different error to the previous errors reported in October 2025).

I think this is due to pull request 4082 which removes spdlog and provides their own library of it.

The solution seems to be to add -DBUILD_LIBMAMBA_SPDLOG=ON to the CMake configuration arguments of the initial build to create the library. Then add -Dlibmamba-spdlog_DIR=$PWD/../../install/lib/cmake/libmamba-spdlog/ to the exported CMAKE_ARGS before building the wheel. At least, that results in a successful build for me.

Hey, I tried to update my system and get the same error message as micwoy92. Version 2.5.0-1

==> Making package: micromamba 2.5.0-1 (Sat 10 Jan 2026 12:32:16 PM CET)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> WARNING: Using existing $srcdir/ tree
==> Removing existing $pkgdir/ directory...
==> Starting build()...
-- The C compiler identification is GNU 15.2.1
-- The CXX compiler identification is GNU 15.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Building libmamba v2.5.0
-- libmamba binary version: v5.0.1
-- Found Python3: /usr/bin/python3.13 (found version "3.13.11") found components: Interpreter
-- Found nlohmann_json: /usr/share/cmake/nlohmann_json/nlohmann_jsonConfig.cmake (found version "3.12.0")
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- Found PkgConfig: /usr/bin/pkg-config (found version "2.5.1")
-- Found Libsolv: /usr/include (found version "0.7.35")
-- Setting LTO for target libmamba::solv-cpp
-- Adding shared libmamba target
-- Setting LTO for target libmamba::libmamba-dyn
   -> Dynamically linking against libmamba (shared) dependencies
-- Found CURL: /usr/lib/libcurl.so (found version "8.18.0")
-- Found LibArchive: /usr/lib/libarchive.so (found version "3.8.5")
-- Found BZip2: /usr/lib/libbz2.so (found version "1.0.8")
-- Looking for BZ2_bzCompressInit
-- Looking for BZ2_bzCompressInit - found
-- Found OpenSSL: /usr/lib/libcrypto.so (found version "3.6.0")
CMake Error at libmambapy/CMakeLists.txt:20 (find_package):
  Could not find a package configuration file provided by "libmamba-spdlog"
  with any of the following names:

    libmamba-spdlogConfig.cmake
    libmamba-spdlog-config.cmake

  Add the installation prefix of "libmamba-spdlog" to CMAKE_PREFIX_PATH or
  set "libmamba-spdlog_DIR" to a directory containing one of the above files.
  If "libmamba-spdlog" provides a separate development package or SDK, be
  sure it has been installed.


-- Configuring incomplete, errors occurred!
==> ERROR: A failure occurred in build().
    Aborting...
 -> error making: micromamba-exit status 4
 -> Failed to install the following packages. Manual intervention is required:
micromamba - exit status 4

Had to change SKBUILD_CONFIGURE_OPTIONS to CMAKE_ARGS in PKGBUILD

build() {
  cmake \
    -S "${_pkgname}-${pkgver}" \
    -B build/ \
    -G Ninja \
    -D CMAKE_INSTALL_PREFIX="/usr" \
    -D CMAKE_BUILD_TYPE=Release \
    -D BUILD_LIBMAMBA=ON \
    -D BUILD_LIBMAMBAPY=ON \
    -D BUILD_MICROMAMBA=ON \
    -D BUILD_SHARED=ON \
    -D CMAKE_BUILD_WITH_INSTALL_RPATH=ON
  cmake --build build --parallel "$(nproc)"
  cmake --install build --prefix install

  cd "${_pkgname}-${pkgver}/libmambapy"
  #export SKBUILD_CONFIGURE_OPTIONS="\
  export CMAKE_ARGS="\
    -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON \
    -DBUILD_LIBMAMBA=ON \
    -DBUILD_LIBMAMBAPY=ON \
    -DBUILD_MICROMAMBA=OFF \
    -DBUILD_MAMBA_PACKAGE=OFF \
    -Dlibmamba_ROOT=$PWD/../../install"
  python -m build --wheel --no-isolation --skip-dependency-check
}

Building fails for me:

* Building wheel...
*** scikit-build-core 0.11.6 using CMake 4.1.2 (wheel)
*** Configuring CMake...
loading initial cache file /tmp/tmpavlu3_n5/build/CMakeInit.txt
-- The C compiler identification is GNU 15.2.1
-- The CXX compiler identification is GNU 15.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:13 (find_package):
  Could not find a package configuration file provided by "libmamba" with any
  of the following names:

    libmambaConfig.cmake
    libmamba-config.cmake

  Add the installation prefix of "libmamba" to CMAKE_PREFIX_PATH or set
  "libmamba_DIR" to a directory containing one of the above files.  If
  "libmamba" provides a separate development package or SDK, be sure it has
  been installed.


-- Configuring incomplete, errors occurred!

*** CMake configuration failed

ERROR Backend subprocess exited when trying to invoke build_wheel
==> ERROR: A failure occurred in build().
    Aborting...

Please remove the sed command that replaces certain paths in the pybind patch - it’s not needed anymore and fails with 2.3.3. Thanks!

Edit: Without the sed command, the patch succeeds, but then I run into the same issues as @kamocat shared below