♻️ Replace pybind11 with nanobind

.clang-tidy

@@ -74,5 +74,3 @@ CheckOptions:
     value: CamelCase
   - key: readability-identifier-naming.VariableCase
     value: camelBack
-  - key: misc-include-cleaner.IgnoreHeaders
-    value: pybind11/detail/.*

.github/workflows/ci.yml

@@ -150,7 +150,7 @@ jobs:
       clang-version: 20
       cmake-args: -DBUILD_MQT_DDSIM_BINDINGS=ON
       files-changed-only: true
-      install-pkgs: "pybind11==3.0.1"
+      install-pkgs: "nanobind==2.10.2"
       setup-python: true
       cpp-linter-extra-args: "-std=c++20"
 

.pre-commit-config.yaml

@@ -131,7 +131,7 @@ repos:
       - id: disallow-caps
         name: Disallow improper capitalization
         language: pygrep
-        entry: PyBind|Numpy|Cmake|CCache|Github|PyTest|Mqt|Tum
+        entry: Nanobind|Numpy|Cmake|CCache|Github|PyTest|Mqt|Tum
         exclude: .pre-commit-config.yaml
 
   # Check best practices for scientific Python code

CHANGELOG.md

@@ -11,6 +11,8 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 
 ### Changed
 
+- ♻️ Migrate Python bindings from `pybind11` to `nanobind` ([#766]) ([**@denialhaag**])
+- 📦️ Provide Stable ABI wheels for Python 3.12+ ([#766]) ([**@denialhaag**])
 - 👷 Stop testing on `ubuntu-22.04` and `ubuntu-22.04-arm` runners ([#740]) ([**@denialhaag**])
 - 👷 Stop testing with `clang-19` and start testing with `clang-21` ([#740]) ([**@denialhaag**])
 - 👷 Fix macOS tests with Homebrew Clang via new `munich-quantum-toolkit/workflows` version ([#740]) ([**@denialhaag**])
@@ -86,6 +88,7 @@ _📚 Refer to the [GitHub Release Notes] for previous changelogs._
 
 <!-- PR links -->
 
+[#766]: https://github.com/munich-quantum-toolkit/ddsim/pull/766
 [#740]: https://github.com/munich-quantum-toolkit/ddsim/pull/740
 [#681]: https://github.com/munich-quantum-toolkit/ddsim/pull/681
 [#674]: https://github.com/munich-quantum-toolkit/ddsim/pull/674

CMakeLists.txt

@@ -39,10 +39,8 @@ if(BUILD_MQT_DDSIM_BINDINGS)
   endif()
 
   # top-level call to find Python
-  find_package(
-    Python 3.10 REQUIRED
-    COMPONENTS Interpreter Development.Module
-    OPTIONAL_COMPONENTS Development.SABIModule)
+  find_package(Python 3.10 REQUIRED COMPONENTS Interpreter Development.Module
+                                               ${SKBUILD_SABI_COMPONENT})
 endif()
 
 # check if this is the master project or used via add_subdirectory

UPGRADING.md

@@ -4,12 +4,24 @@ This document describes breaking changes and how to upgrade. For a complete list
 
 ## [Unreleased]
 
-### Removal of Python 3.13t wheels
+### Python wheels
 
+This release contains two changes to the distributed wheels.
+
+First, we have removed all wheels for Python 3.13t.
 Free-threading Python was introduced as an experimental feature in Python 3.13.
 It became stable in Python 3.14.
-To conserve space on PyPI and to reduce the CD build times, we have removed all wheels for Python 3.13t from our CI.
-We continue to provide wheels for the regular Python versions 3.10 to 3.14, as well as 3.14t.
+
+Second, for Python 3.12+, we are now providing Stable ABI wheels instead of separate version-specific wheels.
+This was enabled by migrating our Python bindings from `pybind11` to `nanobind`.
+
+Both of these changes were made in the interest of conserving PyPI space and reducing CI/CD build times.
+The full list of wheels now reads:
+
+- 3.10
+- 3.11
+- 3.12+ Stable ABI
+- 3.14t
 
 ## [2.1.0]
 

bindings/CMakeLists.txt

@@ -25,7 +25,7 @@ list(
   ${BASEPOINT}/../../core/lib
   ${BASEPOINT}/../../core/lib64)
 
-add_mqt_python_binding(
+add_mqt_python_binding_nanobind(
   DDSIM
   ${MQT_DDSIM_TARGET_NAME}-bindings
   bindings.cpp
@@ -34,5 +34,4 @@ add_mqt_python_binding(
   INSTALL_DIR
   .
   LINK_LIBS
-  MQT::DDSim
-  pybind11_json)
+  MQT::DDSim)