feat: Integrate resolvo as a solver

.github/workflows/static_build.yml

@@ -65,6 +65,62 @@ jobs:
           repository: conda-forge/micromamba-feedstock
           ref: dev
           path: micromamba-feedstock
+      # Temporary: use shared resolvo-cpp until static builds are on conda-forge.
+      - name: Add resolvo-cpp host dependency to feedstock recipe
+        run: |
+          python <<'PY'
+          from pathlib import Path
+
+          path = Path("micromamba-feedstock/recipe/meta.yaml")
+          text = path.read_text()
+          dep = "    - resolvo-cpp 0.3.0\n"
+          if "resolvo-cpp" not in text:
+              needle = "    - simdjson-static >=3.3.0\n"
+              if needle not in text:
+                  raise SystemExit(f"Could not find anchor {needle!r} in {path}")
+              path.write_text(text.replace(needle, needle + dep, 1))
+          PY
+      # Temporary: ship libresolvo_cpp in the micromamba package until resolvo-cpp is static on conda-forge.
+      - name: Patch feedstock build.sh for resolvo DSO
+        run: |
+          python <<'PY'
+          from pathlib import Path
+
+          path = Path("micromamba-feedstock/recipe/build.sh")
+          text = path.read_text()
+          if "libresolvo_cpp" in text:
+              print(f"{path} already copies libresolvo_cpp")
+          else:
+              needle = "cmake --install build/\n\n# remove everything related to"
+              block = """cmake --install build/
+
+          # Temporary: resolvo-cpp is only available as a shared library until static builds are
+          # published on conda-forge. Ship the DSO in $PREFIX/lib so @rpath/../lib resolves when
+          # micromamba is used outside a full conda env (e.g. CI artifact tests).
+          install -d "${PREFIX}/lib"
+          _resolvo_copied=0
+          for _resolvo_lib in \\
+              "${BUILD_PREFIX}/lib/libresolvo_cpp.dylib" \\
+              "${BUILD_PREFIX}/lib/libresolvo_cpp.so" \\
+              "${PREFIX}/lib/libresolvo_cpp.dylib" \\
+              "${PREFIX}/lib/libresolvo_cpp.so"; do
+            if [[ -f "${_resolvo_lib}" ]]; then
+              cp -f "${_resolvo_lib}" "${PREFIX}/lib/"
+              _resolvo_copied=1
+              break
+            fi
+          done
+          if [[ "${_resolvo_copied}" -eq 0 ]]; then
+            echo "libresolvo_cpp not found in BUILD_PREFIX or PREFIX" >&2
+            exit 1
+          fi
+
+          # remove everything related to"""
+              if needle not in text:
+                  raise SystemExit(f"Could not find anchor in {path}")
+              path.write_text(text.replace(needle, block, 1))
+              print(f"Patched {path} to copy libresolvo_cpp into the package")
+          PY
       - name: Disable output validation
         if: ${{ matrix.platform == 'osx' }}
         run: |
@@ -141,6 +197,25 @@ jobs:
             "micromamba-feedstock/build_artifacts/${{ matrix.platform }}-${{ matrix.arch }}/"micromamba-*.tar.bz2 "pkg/"
           mkdir -p "${{ github.workspace }}/artifacts"
           cp pkg/bin/micromamba "${{ github.workspace }}/artifacts"
+          # Temporary: static micromamba links shared resolvo-cpp (@rpath/../lib) until
+          # resolvo-cpp static libraries are published on conda-forge. Copy the DSO for
+          # artifact tests (the conda package only declares it as a run dependency).
+          mkdir -p "${{ github.workspace }}/lib"
+          shopt -s nullglob
+          _resolvo_copied=0
+          for _resolvo_lib in \
+            pkg/lib/libresolvo_cpp.* \
+            "${MAMBA_ROOT_PREFIX}/envs/mambabuild/lib/libresolvo_cpp."* \
+            "${MAMBA_ROOT_PREFIX}"/pkgs/resolvo-cpp-*/lib/libresolvo_cpp.* \
+            micromamba-feedstock/build_artifacts/*/_h_env*/lib/libresolvo_cpp.*; do
+            cp "${_resolvo_lib}" "${{ github.workspace }}/lib/"
+            _resolvo_copied=1
+            break
+          done
+          if [[ "${_resolvo_copied}" -eq 0 ]]; then
+            echo "libresolvo_cpp shared library not found for artifact tests" >&2
+            exit 1
+          fi
 
       - name: Test basic commands
         if: ${{ matrix.arch != 'aarch64' && matrix.arch != 'ppc64le' }}
@@ -186,6 +261,7 @@ jobs:
             cpp-expected
             nlohmann_json
             simdjson-static>=3.3.0
+            resolvo-cpp==0.3.0
             spdlog>=1.16.0
             fmt>=11.1.0
             yaml-cpp-static>=0.8.0

cmake/modules/CheckResolvoConditions.cmake

@@ -0,0 +1,39 @@
+# Detect resolvo-cpp >= 0.3.0 builds that export ConditionId / ConditionalRequirement. win-64 0.3.0
+# (h0a879f1_1) predates this API; linux-64 0.3.0 (hf9e0b3e_1) includes it. Temporary until
+# conda-forge republishes a consistent resolvo-cpp 0.3.0 on all platforms.
+
+set(LIBMAMBA_RESOLVO_HAS_CONDITIONS FALSE)
+
+find_file(
+    _libmamba_resolvo_dep_header
+    NAMES resolvo/resolvo_dependency_provider.h
+    PATHS ${CMAKE_PREFIX_PATH}
+    PATH_SUFFIXES include Library/include
+    NO_DEFAULT_PATH
+)
+if(NOT _libmamba_resolvo_dep_header)
+    find_file(
+        _libmamba_resolvo_dep_header
+        NAMES resolvo/resolvo_dependency_provider.h
+        PATH_SUFFIXES include Library/include
+    )
+endif()
+
+if(_libmamba_resolvo_dep_header)
+    file(READ "${_libmamba_resolvo_dep_header}" _libmamba_resolvo_dep_header_content)
+    if(_libmamba_resolvo_dep_header_content MATCHES "using cbindgen_private::ConditionId;")
+        set(LIBMAMBA_RESOLVO_HAS_CONDITIONS TRUE)
+    endif()
+endif()
+
+if(LIBMAMBA_RESOLVO_HAS_CONDITIONS)
+    message(STATUS "resolvo-cpp: conditional requirements API available")
+else()
+    message(
+        STATUS
+            "resolvo-cpp: legacy API without conditional requirements (temporary platform workaround)"
+    )
+endif()
+
+unset(_libmamba_resolvo_dep_header)
+unset(_libmamba_resolvo_dep_header_content)

cmake/modules/FixResolvoWindows.cmake

@@ -0,0 +1,40 @@
+# Temporary workaround until resolvo-cpp static libraries are published on conda-forge. resolvo-cpp
+# 0.3.0 on Windows installs Library/bin/resolvo_cpp.dll and Library/lib/resolvo_cpp.lib, but
+# ResolvoConfig.cmake still references the 0.2.x layout (Library/lib/resolvo_cpp.dll and
+# resolvo_cpp.dll.lib).
+
+if(NOT WIN32 OR NOT TARGET resolvo_cpp-shared)
+    return()
+endif()
+
+if(DEFINED ENV{LIBRARY_PREFIX})
+    set(_resolvo_prefix "$ENV{LIBRARY_PREFIX}")
+elseif(DEFINED ENV{CONDA_PREFIX})
+    set(_resolvo_prefix "$ENV{CONDA_PREFIX}/Library")
+else()
+    get_target_property(_resolvo_implib resolvo_cpp-shared IMPORTED_IMPLIB)
+    if(_resolvo_implib)
+        get_filename_component(_resolvo_prefix "${_resolvo_implib}" DIRECTORY)
+        get_filename_component(_resolvo_prefix "${_resolvo_prefix}" DIRECTORY)
+    endif()
+endif()
+
+if(NOT _resolvo_prefix)
+    message(WARNING "Could not determine resolvo-cpp prefix for Windows import fix")
+    return()
+endif()
+
+set(_resolvo_dll "${_resolvo_prefix}/bin/resolvo_cpp.dll")
+set(_resolvo_lib "${_resolvo_prefix}/lib/resolvo_cpp.lib")
+
+if(EXISTS "${_resolvo_lib}" AND EXISTS "${_resolvo_dll}")
+    set_target_properties(
+        resolvo_cpp-shared
+        PROPERTIES IMPORTED_IMPLIB "${_resolvo_lib}" IMPORTED_LOCATION "${_resolvo_dll}"
+    )
+    message(STATUS "Adjusted Resolvo Windows import lib to ${_resolvo_lib}")
+endif()
+
+unset(_resolvo_prefix)
+unset(_resolvo_dll)
+unset(_resolvo_lib)

dev/environment-dev.yml

@@ -17,6 +17,7 @@ dependencies:
   - libarchive>=3.8 lgpl_*
   - libcurl >=7.86
   - libsodium
+  - resolvo-cpp==0.3.0
   - libsolv >=0.7.18
   - libmsgpack-c
   - nlohmann_json

dev/environment-micromamba-static.yml

@@ -18,6 +18,7 @@ dependencies:
   - simdjson-static >=3.3.0
   - spdlog >=1.16.0
   - fmt >=11.1.0
+  - resolvo-cpp==0.3.0
   - libsolv-static >=0.7.24
   - yaml-cpp-static >=0.8.0
   - reproc-static >=14.2.4.post0

dev/micromamba_windows_allowed_dlls.tsv

@@ -28,3 +28,4 @@ api-ms-win-crt-utility-l1-1-0.dll	UCRT (ucrt)	UCRT forwarder: utility routines (
 MSVCP140.dll	MSVC runtime (vc14_runtime)	Microsoft C++ standard library runtime (/MD builds).
 VCRUNTIME140.dll	MSVC runtime (vc14_runtime)	Microsoft C runtime helpers (exceptions, EH scaffolding).
 VCRUNTIME140_1.dll	MSVC runtime (vc14_runtime)	Additional MSVC C++ exception-handling support on x64.
+resolvo_cpp.dll	resolvo-cpp (conda-forge)	Temporary: shared resolvo C++ bindings until resolvo-cpp static libraries are published on conda-forge.

libmamba/CMakeLists.txt

@@ -196,6 +196,9 @@ set(
     ${LIBMAMBA_SOURCE_DIR}/solver/libsolv/repo_info.cpp
     ${LIBMAMBA_SOURCE_DIR}/solver/libsolv/solver.cpp
     ${LIBMAMBA_SOURCE_DIR}/solver/libsolv/unsolvable.cpp
+    # Solver resolvo implementation
+    ${LIBMAMBA_SOURCE_DIR}/solver/resolvo/database.cpp
+    ${LIBMAMBA_SOURCE_DIR}/solver/resolvo/solver.cpp
     # Artifacts validation
     ${LIBMAMBA_SOURCE_DIR}/validation/errors.cpp
     ${LIBMAMBA_SOURCE_DIR}/validation/keys.cpp
@@ -355,12 +358,18 @@ set(
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/problems_graph.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/request.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/solution.hpp
+    ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/database.hpp
+    ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/database_utils.hpp
+    ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/solver_factory.hpp
     # Solver libsolv implementation
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/libsolv/database.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/libsolv/parameters.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/libsolv/repo_info.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/libsolv/solver.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/libsolv/unsolvable.hpp
+    # Solver resolvo implementation
+    ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/resolvo/database.hpp
+    ${LIBMAMBA_INCLUDE_DIR}/mamba/solver/resolvo/solver.hpp
     # Artifacts validation
     ${LIBMAMBA_INCLUDE_DIR}/mamba/validation/errors.hpp
     ${LIBMAMBA_INCLUDE_DIR}/mamba/validation/keys.hpp
@@ -447,6 +456,9 @@ find_package(yaml-cpp CONFIG REQUIRED)
 find_package(reproc CONFIG REQUIRED)
 find_package(reproc++ CONFIG REQUIRED)
 find_package(Libsolv MODULE REQUIRED)
+find_package(Resolvo CONFIG REQUIRED)
+include(FixResolvoWindows)
+include(CheckResolvoConditions)
 find_package(msgpack-c CONFIG REQUIRED)
 add_subdirectory(ext/solv-cpp)
 
@@ -496,14 +508,15 @@ macro(libmamba_create_target target_name linkage output_name)
 
         target_link_libraries(
             ${target_name}
-            PUBLIC fmt::fmt-header-only yaml-cpp::yaml-cpp ${MSGPACK_TARGET}
+            PUBLIC
+                fmt::fmt-header-only yaml-cpp::yaml-cpp ${MSGPACK_TARGET} simdjson::simdjson_static
             PRIVATE
                 reproc
                 reproc++
-                simdjson::simdjson_static
                 solv::libsolv_static
                 solv::libsolvext_static
                 solv::cpp
+                Resolvo::Resolvo
         )
 
         if(UNIX)
@@ -675,19 +688,24 @@ macro(libmamba_create_target target_name linkage output_name)
         target_link_libraries(
             ${target_name}
             PUBLIC
-                ${LIBSOLV_LIBRARIES} ${LIBSOLVEXT_LIBRARIES} yaml-cpp::yaml-cpp fmt::fmt msgpack-c
+                ${LIBSOLV_LIBRARIES}
+                ${LIBSOLVEXT_LIBRARIES}
+                yaml-cpp::yaml-cpp
+                fmt::fmt
+                msgpack-c
+                simdjson::simdjson
             PRIVATE
                 ${LibArchive_LIBRARIES}
                 ${CURL_LIBRARIES}
                 ${OPENSSL_LIBRARIES}
                 BZip2::BZip2
                 reproc
                 reproc++
-                simdjson::simdjson
                 zstd::libzstd_shared
                 solv::libsolv
                 solv::libsolvext
                 solv::cpp
+                Resolvo::Resolvo
         )
         # CMake 3.17 provides a LibArchive::LibArchive target that could be used instead of
         # LIBRARIES/INCLUDE_DIRS
@@ -736,6 +754,10 @@ macro(libmamba_create_target target_name linkage output_name)
         target_link_libraries(${target_name} PUBLIC Threads::Threads)
     endif()
 
+    if(LIBMAMBA_RESOLVO_HAS_CONDITIONS)
+        target_compile_definitions(${target_name} PUBLIC LIBMAMBA_RESOLVO_HAS_CONDITIONS)
+    endif()
+
     list(APPEND libmamba_targets ${target_name})
     add_library(mamba::${target_name} ALIAS ${target_name})
 endmacro()

libmamba/include/mamba/core/context.hpp

@@ -103,6 +103,7 @@ namespace mamba
         // Configurable
         bool mamba_repodata_parsing = true;
         bool experimental_matchspec_parsing = false;
+        bool experimental_resolvo_solver = false;
         bool debug = false;
         bool use_uv = false;
 

libmamba/include/mamba/solver/database.hpp

@@ -0,0 +1,62 @@
+// Copyright (c) 2026, QuantStack and Mamba Contributors
+//
+// Distributed under the terms of the BSD 3-Clause License.
+//
+// The full license is in the file LICENSE, distributed with this software.
+
+#ifndef MAMBA_SOLVER_DATABASE_HPP
+#define MAMBA_SOLVER_DATABASE_HPP
+
+#include <string>
+#include <variant>
+#include <vector>
+
+#include "mamba/fs/filesystem.hpp"
+#include "mamba/specs/channel.hpp"
+#include "mamba/specs/match_spec.hpp"
+#include "mamba/specs/package_info.hpp"
+
+namespace mamba::solver
+{
+    class Database
+    {
+    public:
+
+        virtual ~Database() = default;
+
+        virtual void add_repo_from_repodata_json(
+            const fs::u8path& filename,
+            const std::string& repo_url,
+            const std::string& channel_id,
+            bool verify_artifacts = false
+        ) = 0;
+
+        virtual void add_repo_from_packages(
+            const std::vector<specs::PackageInfo>& packages,
+            const std::string& repo_name,
+            bool pip_as_python_dependency = false
+        ) = 0;
+
+        virtual void set_installed_repo(const std::string& repo_name) = 0;
+
+        virtual bool has_package(const specs::MatchSpec& spec) = 0;
+    };
+
+    namespace libsolv
+    {
+        class Database;
+    }
+
+    namespace resolvo
+    {
+        class Database;
+    }
+
+    using DatabaseVariant = std::variant<libsolv::Database, resolvo::Database>;
+
+    // Remove or comment out the inline database_has_package function if DatabaseVariant is not
+    // visible or causes errors inline auto database_has_package(DatabaseVariant& database, const
+    // specs::MatchSpec& spec) -> bool;
+}
+
+#endif  // MAMBA_SOLVER_DATABASE_HPP

libmamba/include/mamba/solver/database_utils.hpp

@@ -0,0 +1,24 @@
+#ifndef MAMBA_SOLVER_DATABASE_UTILS_HPP
+#define MAMBA_SOLVER_DATABASE_UTILS_HPP
+
+#include <stdexcept>
+
+#include "mamba/solver/database.hpp"
+
+namespace mamba::solver
+{
+    inline bool database_has_package(DatabaseVariant& database, const specs::MatchSpec& spec)
+    {
+        if (auto* libsolv_db = std::get_if<libsolv::Database>(&database))
+        {
+            return libsolv_db->has_package(spec);
+        }
+        else if (auto* resolvo_db = std::get_if<resolvo::Database>(&database))
+        {
+            return resolvo_db->has_package(spec);
+        }
+        throw std::runtime_error("Invalid database variant");
+    }
+}
+
+#endif  // MAMBA_SOLVER_DATABASE_UTILS_HPP