Merge pull request #2701 from Metadorius/feature/net461

filmor · web-flow · commit 023838701dae · 2026-05-05T21:54:22.000+02:00
Support .NET Framework 4.6.1
diff --git a/AUTHORS.md b/AUTHORS.md
@@ -89,3 +89,4 @@
 -   Ehsan Iran-Nejad ([@eirannejad](https://github.com/eirannejad))
 -   ([@legomanww](https://github.com/legomanww))
 -   ([@gertdreyer](https://github.com/gertdreyer))
+-   Kerbiter ([@Metadorius](https://github.com/Metadorius))
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,12 +10,13 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 ### Added
 
 -  Support `del obj[...]` for types derived from `IList<T>` and `IDictionary<K, V>`
+-  Support for .NET Framework 4.6.1 (#2701)
 
 ### Changed
 ### Fixed
 
 -  Fixed crash when trying to `del clrObj[...]` for non-arrays
-- ci: properly exclude job (#2542)
+-  ci: properly exclude job (#2542)
 
 ## [3.0.5](https://github.com/pythonnet/pythonnet/releases/tag/v3.0.5) - 2024-12-13
 
diff --git a/Justfile b/Justfile
@@ -0,0 +1,14 @@
+default:
+    @just --choose
+
+setup:
+    dotnet restore
+    uv sync
+
+docs:
+    doxygen doc/Doxyfile
+    uv run --group doc sphinx-build doc/source/ ./doc/build/html/
+
+build-wheels:
+    uv build
+    uv build --wheel -C="--global-option=--net46-support"
diff --git a/MANIFEST.in b/MANIFEST.in
@@ -1,6 +1,7 @@
 graft src/runtime
 prune src/runtime/obj
 prune src/runtime/bin
+graft src/compat
 include src/pythonnet.snk
 include Directory.Build.*
 include pythonnet.sln
diff --git a/doc/source/python.rst b/doc/source/python.rst
@@ -45,7 +45,8 @@ Mono (``mono``)
 
 .NET Framework (``netfx``)
     Default on Windows and also only supported there. Must be at least version
-    4.7.2.
+    4.6.1, with 4.7.2 or later recommended. For .NET 4.6 support, the wheel has
+    to be built with the environment variable `PYTHONNET_BUILD_NET46_SUPPORT=1`.
 
 .NET Core (``coreclr``)
     Self-contained is not supported, must be at least version 3.1.
diff --git a/pyproject.toml b/pyproject.toml
@@ -55,6 +55,9 @@ email = "pythonnet@python.org"
 Homepage = "https://pythonnet.github.io/"
 Sources = "https://github.com/pythonnet/pythonnet"
 
+[project.entry-points.pyinstaller40]
+hook-dirs = "pythonnet._pyinstaller:get_hook_dirs"
+
 [tool.setuptools]
 zip-safe = false
 py-modules = ["clr"]
diff --git a/pythonnet/_pyinstaller/__init__.py b/pythonnet/_pyinstaller/__init__.py
@@ -0,0 +1,4 @@
+import os
+
+def get_hook_dirs():
+    return [os.path.dirname(__file__)]
diff --git a/pythonnet/_pyinstaller/hook-clr.py b/pythonnet/_pyinstaller/hook-clr.py
@@ -0,0 +1,9 @@
+from PyInstaller.utils.hooks import collect_data_files, collect_dynamic_libs
+
+try:
+    binaries = collect_dynamic_libs("pythonnet")
+    datas = collect_data_files("pythonnet")
+except Exception:
+    # name conflict with https://pypi.org/project/clr/, do not crash if just clr is present
+    binaries = []
+    datas = []
diff --git a/setup.py b/setup.py
@@ -3,15 +3,20 @@
 import distutils
 from distutils.command.build import build as _build
 from setuptools.command.develop import develop as _develop
-from wheel.bdist_wheel import bdist_wheel as _bdist_wheel
 from setuptools import Distribution
 from setuptools import setup, Command
 
 import os
+import sys
 
 # Disable SourceLink during the build until it can read repo-format v1, #1613
 os.environ["EnableSourceControlManagerQueries"] = "false"
 
+NET46_SUPPORT_OPTION = "--net46-support"
+NET46_SUPPORT = NET46_SUPPORT_OPTION in sys.argv
+if NET46_SUPPORT:
+    sys.argv.remove(NET46_SUPPORT_OPTION)
+
 
 class DotnetLib:
     def __init__(self, name, path, **kwargs):
@@ -106,33 +111,27 @@ def install_for_development(self):
         return super().install_for_development()
 
 
-class bdist_wheel(_bdist_wheel):
-    def finalize_options(self):
-        # Monkey patch bdist_wheel to think the package is pure even though we
-        # include DLLs
-        super().finalize_options()
-        self.root_is_pure = True
-
-
 # Monkey-patch Distribution s.t. it supports the dotnet_libs attribute
 Distribution.dotnet_libs = None
 
 cmdclass = {
     "build": build,
     "build_dotnet": build_dotnet,
     "develop": develop,
-    "bdist_wheel": bdist_wheel,
 }
 
-dotnet_libs = [
-    DotnetLib(
-        "python-runtime",
-        "src/runtime/Python.Runtime.csproj",
-        output="pythonnet/runtime",
-    )
-]
+
+if NET46_SUPPORT:
+    csproj = "src/compat/Python.Runtime.Compat.csproj"
+    plat_name = "win32"
+else:
+    csproj = "src/runtime/Python.Runtime.csproj"
+    plat_name = "any"
+
+dotnet_libs = [DotnetLib("python-runtime", csproj, output="pythonnet/runtime")]
 
 setup(
     cmdclass=cmdclass,
     dotnet_libs=dotnet_libs,
+    options={"bdist_wheel": {"plat_name": plat_name}},
 )
diff --git a/src/compat/Python.Runtime.Compat.csproj b/src/compat/Python.Runtime.Compat.csproj
@@ -0,0 +1,13 @@
+<!-- A dummy project to force MSBuild to package .NET 4.6.1 requirements -->
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net461</TargetFramework>
+    <OutputType>Library</OutputType>
+    <!-- Don't copy the dummy assembly/pdb to output; we only need the resolved references -->
+    <CopyBuildOutputToOutputDirectory>false</CopyBuildOutputToOutputDirectory>
+    <CopyOutputSymbolsToOutputDirectory>false</CopyOutputSymbolsToOutputDirectory>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\runtime\Python.Runtime.csproj" />
+  </ItemGroup>
+</Project>
diff --git a/src/runtime/Loader.cs b/src/runtime/Loader.cs
@@ -1,4 +1,5 @@
 using System;
+using System.IO;
 using System.Text;
 
 namespace Python.Runtime
@@ -12,6 +13,28 @@ public unsafe static int Initialize(IntPtr data, int size)
         {
             try
             {
+                // On .NET Framework, the host is python.exe which has no binding
+                // redirects for netstandard2.0 shims (e.g. RuntimeInformation
+                // Version=0.0.0.0 vs the 4.0.2.0 shim on disk). Binding redirects
+                // via config files can't be injected after AppDomain creation, so
+                // resolve assemblies from our runtime directory directly.
+                // Only needed on .NET Framework; on .NET (Core) this causes
+                // duplicate assembly loads, as .deps.json is respected and
+                // the correct assembly is already found.
+                if (typeof(object).Assembly.GetName().Name == "mscorlib")
+                {
+                    AppDomain.CurrentDomain.AssemblyResolve += (_, args) =>
+                    {
+                        var name = new System.Reflection.AssemblyName(args.Name);
+                        var dir = Path.GetDirectoryName(typeof(Loader).Assembly.Location);
+                        var path = Path.Combine(dir, name.Name + ".dll");
+
+                        return File.Exists(path)
+                            ? System.Reflection.Assembly.LoadFrom(path)
+                            : null;
+                    };
+                }
+
                 var dllPath = Encodings.UTF8.GetString((byte*)data.ToPointer(), size);
 
                 if (!string.IsNullOrEmpty(dllPath))
