gh-142466: Pixi package definitions for downstream use

.gitignore

@@ -45,6 +45,7 @@ gmon.out
 .pytest_cache/
 .ruff_cache/
 .DS_Store
+.pixi/
 
 *.exe
 

Tools/README

@@ -43,6 +43,8 @@ patchcheck      Tools for checking and applying patches to the Python source cod
 
 peg_generator   PEG-based parser generator (pegen) used for new parser.
 
+pixi-packages   Pixi package definitions for downstream from-source builds
+
 scripts         A number of useful single-file programs, e.g. run_tests.py
                 which runs the Python test suite.
 

Tools/pixi-packages/README

@@ -0,0 +1,36 @@
+## CPython Pixi Packages
+
+This directory contains definitions for [Pixi packages](https://pixi.sh/latest/reference/pixi_manifest/#the-package-section)
+which can be built from the CPython source code.
+
+Downstream developers can make use of these packages by adding them as git dependencies in a
+[Pixi workspace](https://pixi.sh/latest/first_workspace/), like:
+
+```toml
+[dependencies]
+python = { git = "https://github.com/python/cpython", subdirectory = "Tools/pixi-packages/asan" }
+```
+
+This is particularly useful when developers need to build CPython from source
+(for example, for an ASan-instrumented build), as it does not require any manual
+cloning or building steps. Instead, Pixi will automatically handle both the building
+and installation of the package.
+
+Each package definition is contained in a subdirectory, but they share the build script
+`build.sh` in this directory. Currently defined package variants:
+
+- `default`
+- `asan`: ASan-instrumented build with `PYTHON_ASAN=1`
+
+### Maintenance
+
+- the `version` fields in each `recipe.yaml` should be kept up to date with the Python version
+- dependency requirements should be kept up to date in each `recipe.yaml`
+- `build.sh` should be updated for any breaking changes in the `configure` and `make` workflow
+
+### Opportunities for future improvement
+
+- more package variants (e.g. TSan, UBSan)
+- support for Windows
+- using a single `pixi.toml` and `recipe.yaml` for all package variants is blocked on https://github.com/prefix-dev/pixi/issues/4599
+- a workaround can be removed from the build script once https://github.com/prefix-dev/rattler-build/issues/2012 is resolved

Tools/pixi-packages/asan/pixi.toml

@@ -0,0 +1,8 @@
+[workspace]
+channels = ["https://prefix.dev/conda-forge"]
+platforms = ["osx-arm64", "linux-64"]
+preview = ["pixi-build"]
+
+[package.build.backend]
+name = "pixi-build-rattler-build"
+version = "*"

Tools/pixi-packages/asan/recipe.yaml

@@ -0,0 +1,65 @@
+context:
+  # XXX: keep up to date
+  version: "3.15"
+
+package:
+  name: python
+  version: ${{ version }}
+
+source:
+  - path: ../../..
+
+build:
+  files:
+    exclude:
+      - "*.o"
+  script:
+    file: ../build.sh
+    env:
+      PYTHON_VARIANT: "asan"
+
+# XXX: maybe not all requirements necessary
+# derived from https://github.com/conda-forge/python-feedstock/blob/main/recipe/meta.yaml
+requirements:
+  build:
+    - ${{ compiler('c') }}
+    - ${{ compiler('cxx') }}
+    - make
+    - libtool
+    - pkg-config
+    # configure script looks for llvm-ar for lto
+    - if: osx
+      then:
+        - llvm-tools
+    - if: linux
+      then:
+        - ld_impl_${{ target_platform }}
+        - binutils_impl_${{ target_platform }}
+    - clang-19
+    - llvm-tools-19
+
+  host:
+    - bzip2
+    - sqlite
+    - liblzma-devel
+    - zlib
+    - zstd
+    - openssl
+    - readline
+    - tk
+    # These two are just to get the headers needed for tk.h, but is unused
+    - xorg-libx11
+    - xorg-xorgproto
+    - ncurses
+    - libffi
+    - if: linux
+      then:
+        - ld_impl_${{ target_platform }}
+        - libuuid
+    - libmpdec-devel
+    - expat
+
+about:
+  homepage: https://www.python.org/
+  license: Python-2.0
+  license_file: LICENSE

Tools/pixi-packages/build.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+if [[ "${PYTHON_VARIANT}" == "asan" ]]; then
+    echo "BUILD TYPE: ASAN"
+    BUILD_DIR="../build_asan"
+    CONFIGURE_EXTRA="--with-address-sanitizer"
+    export PYTHON_ASAN="1"
+    export ASAN_OPTIONS="strict_init_order=true"
+else
+    echo "BUILD TYPE: DEFAULT"
+    BUILD_DIR="../build"
+    CONFIGURE_EXTRA=""
+fi
+
+mkdir -p "${BUILD_DIR}"
+cd "${BUILD_DIR}"
+
+if [[ -f configure-done ]]; then
+    echo "Skipping configure step, already done."
+else
+    "${SRC_DIR}/configure" \
+        --prefix="${PREFIX}" \
+        --oldincludedir="${BUILD_PREFIX}/${HOST}/sysroot/usr/include" \
+        --enable-shared \
+        --srcdir="${SRC_DIR}" \
+        ${CONFIGURE_EXTRA}
+fi
+
+touch configure-done
+
+make -j"${CPU_COUNT}" install
+ln -sf "${PREFIX}/bin/python3" "${PREFIX}/bin/python"
+
+# https://github.com/prefix-dev/rattler-build/issues/2012
+if [[ ${OSTYPE} == "darwin"* ]]; then
+    cp "${BUILD_PREFIX}/lib/clang/21/lib/darwin/libclang_rt.asan_osx_dynamic.dylib" "${PREFIX}/lib/libclang_rt.asan_osx_dynamic.dylib"
+fi

Tools/pixi-packages/default/pixi.toml

@@ -0,0 +1,8 @@
+[workspace]
+channels = ["https://prefix.dev/conda-forge"]
+platforms = ["osx-arm64", "linux-64"]
+preview = ["pixi-build"]
+
+[package.build.backend]
+name = "pixi-build-rattler-build"
+version = "*"

Tools/pixi-packages/default/recipe.yaml

@@ -0,0 +1,63 @@
+context:
+  # XXX: keep up to date
+  version: "3.15"
+
+package:
+  name: python
+  version: ${{ version }}
+
+source:
+  - path: ../../..
+
+build:
+  files:
+    exclude:
+      - "*.o"
+  script:
+    file: ../build.sh
+
+# XXX: maybe not all requirements necessary
+# derived from https://github.com/conda-forge/python-feedstock/blob/main/recipe/meta.yaml
+requirements:
+  build:
+    - ${{ compiler('c') }}
+    - ${{ compiler('cxx') }}
+    - make
+    - libtool
+    - pkg-config
+    # configure script looks for llvm-ar for lto
+    - if: osx
+      then:
+        - llvm-tools
+    - if: linux
+      then:
+        - ld_impl_${{ target_platform }}
+        - binutils_impl_${{ target_platform }}
+    - clang-19
+    - llvm-tools-19
+
+  host:
+    - bzip2
+    - sqlite
+    - liblzma-devel
+    - zlib
+    - zstd
+    - openssl
+    - readline
+    - tk
+    # These two are just to get the headers needed for tk.h, but is unused
+    - xorg-libx11
+    - xorg-xorgproto
+    - ncurses
+    - libffi
+    - if: linux
+      then:
+        - ld_impl_${{ target_platform }}
+        - libuuid
+    - libmpdec-devel
+    - expat
+
+about:
+  homepage: https://www.python.org/
+  license: Python-2.0
+  license_file: LICENSE