Install unisolated packages into the isolated build venv and overlay their cross-build files

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.36.0] - 2026/MM/DD
 
 ### Fixed
 
@@ -50,6 +50,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   setting `UV_BUILD_CONSTRAINT` alongside `PIP_CONSTRAINT` and `PIP_BUILD_CONSTRAINT`.
   [#389](https://github.com/pyodide/pyodide-build/pull/389)
 
+### Changed
+
+- Fixed build-time scripts of unisolated packages (like `f2py` and
+  `numpy-config` from NumPy) not being available on `PATH` during builds.
+  [#21](https://github.com/pyodide/pyodide-build/pull/21)
+
 ## [0.35.1] - 2026/06/13
 
 ### Fixed
@@ -222,12 +228,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Added `pyodide clean recipes`, a CLI command that deletes build files for chosen packages or tags.
-[#254](https://github.com/pyodide/pyodide-build/pull/254)
+  [#254](https://github.com/pyodide/pyodide-build/pull/254)
 
 ## [0.30.8] - 2025/10/22
 
 - `pyodide config` now exposes `dist_dir` variable.
-[#236](https://github.com/pyodide/pyodide-build/pull/236)
+  [#236](https://github.com/pyodide/pyodide-build/pull/236)
 
 - The CMake toolchain file for Pyodide now sets `CMAKE_SHARED_LINKER_FLAGS_INIT` and `CMAKE_MODULE_LINKER_FLAGS_INIT` and
   unset `CMAKE_SHARED_LINKER_FLAGS` to avoid conflicts with the user's settings.

integration_tests/recipes/README.md

@@ -11,6 +11,7 @@ This directory contains a few curated recipes to test the build process of pyodi
 - `pydoc_data`: Unvendored cpython module
 - `boost-histogram``: Tests scikit-build-core and cmake build system.
 - `colorama`: Uses prebuilt wheel as source to check test file unvendoring capabilities.
+- `numpy-scripts-example`: Tests that unisolated package scripts (say, `f2py` or `numpy-config` from NumPy as a build dependency) are available on PATH during builds.
 
 ### For maintainers
 

integration_tests/recipes/numpy-scripts-example/meta.yaml

@@ -0,0 +1,23 @@
+package:
+  name: numpy-scripts-example
+  version: 0.1.0
+  top-level:
+    - numpy_scripts_example
+
+source:
+  path: source
+
+requirements:
+  host:
+    - numpy
+  run:
+    - numpy
+
+about:
+  home: https://github.com/pyodide/pyodide-build
+  summary: Minimal integration test that verifies f2py and numpy-config are on PATH during the build
+  license: MIT
+
+extra:
+  recipe-maintainers:
+    - agriyakhetarpal

integration_tests/recipes/numpy-scripts-example/source/meson.build

@@ -0,0 +1,32 @@
+project('numpy-scripts-example', 'c',
+  version: '0.1.0',
+  license: 'MIT',
+  meson_version: '>= 1.3.0',
+)
+
+py_mod = import('python')
+py3 = py_mod.find_installation()
+py3_dep = py3.dependency()
+
+# The only point of this recipe is to verify that NumPy's console scripts
+# are discoverable on PATH when it is a build-time dependency.
+f2py = find_program('f2py')
+numpy_cflags = run_command('numpy-config', '--cflags', check: true).stdout().strip().split()
+
+incdir_numpy = run_command(py3,
+  ['-c', 'import numpy; print(numpy.get_include())'],
+  check: true,
+).stdout().strip()
+
+py3.install_sources(['numpy_scripts_example/__init__.py'],
+  pure: false,
+  subdir: 'numpy_scripts_example')
+
+py3.extension_module('_add',
+  'numpy_scripts_example/_add.c',
+  include_directories: incdir_numpy,
+  c_args: numpy_cflags,
+  dependencies: py3_dep,
+  install: true,
+  subdir: 'numpy_scripts_example',
+)

integration_tests/recipes/numpy-scripts-example/source/numpy_scripts_example/__init__.py

@@ -0,0 +1,3 @@
+from ._add import add
+
+__all__ = ["add"]

integration_tests/recipes/numpy-scripts-example/source/numpy_scripts_example/_add.c

@@ -0,0 +1,28 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <numpy/arrayobject.h>
+
+static PyObject *
+add(PyObject *self, PyObject *args)
+{
+    double a, b;
+    if (!PyArg_ParseTuple(args, "dd", &a, &b))
+        return NULL;
+    return PyFloat_FromDouble(a + b);
+}
+
+static PyMethodDef methods[] = {
+    {"add", add, METH_VARARGS, "Add two floats."},
+    {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef module = {
+    PyModuleDef_HEAD_INIT, "_add", NULL, -1, methods
+};
+
+PyMODINIT_FUNC
+PyInit__add(void)
+{
+    import_array();
+    return PyModule_Create(&module);
+}

integration_tests/recipes/numpy-scripts-example/source/pyproject.toml

@@ -0,0 +1,9 @@
+[build-system]
+build-backend = "mesonpy"
+requires = ["meson-python", "numpy"]
+
+[project]
+name = "numpy-scripts-example"
+version = "0.1.0"
+requires-python = ">=3.9"
+dependencies = ["numpy"]

pyodide_build/build_env.py

@@ -163,7 +163,6 @@ def get_build_environment_vars(pyodide_root: Path) -> dict[str, str]:
             "PYODIDE": "1",
             # This is the legacy environment variable used for the aforementioned purpose
             "PYODIDE_PACKAGE_ABI": "1",
-            "PYTHONPATH": env["HOSTSITEPACKAGES"],
         }
     )
 
@@ -220,29 +219,82 @@ def get_hostsitepackages() -> str:
     return get_build_flag("HOSTSITEPACKAGES")
 
 
+# TODO: Remove this function (and use remote package index)
+# https://github.com/pyodide/pyodide-build/issues/43
 @functools.cache
-def get_unisolated_packages() -> list[str]:
-    # TODO: Remove this function (and use remote package index)
-    # https://github.com/pyodide/pyodide-build/issues/43
+def get_unisolated_packages() -> dict[str, str]:
+    """
+    Get a map of unisolated packages.
+
+    Unisolated packages are packages that are used during the build process
+    and have some platform-specific files. When these packages are used
+    during the build process, their platform-specific files are replaced with
+    WASM-compatible versions to build the package correctly.
+
+    Returns
+    -------
+    A dictionary of package names and versions.
+    """
     PYODIDE_ROOT = get_pyodide_root()
 
-    unisolated_file = PYODIDE_ROOT / "unisolated.txt"
-    if unisolated_file.exists():
-        # in xbuild env, read from file
-        unisolated_packages = unisolated_file.read_text().splitlines()
+    unisolated_packages: dict[str, str] = {}
+    if in_xbuildenv():
+        unisolated_packages_file = PYODIDE_ROOT / ".." / "requirements.txt"
+
+        if not unisolated_packages_file.exists():
+            raise FileNotFoundError(
+                f"Expected {unisolated_packages_file} to exist in the xbuildenv. "
+                "The xbuildenv archive may be corrupt or from an incompatible version."
+            )
+        for line in unisolated_packages_file.read_text().splitlines():
+            line = line.strip()
+            # The xbuildenv requirements.txt is machine-generated and always
+            # uses pinned name==version entries, but we skip blank lines,
+            # comments, and any non-pinned specs just in case. Shouldn't
+            # really happen though.
+            if not line or line.startswith("#") or "==" not in line:
+                continue
+            name, version = line.split("==", 1)
+            unisolated_packages[name] = version
     else:
         from pyodide_build.recipe.loader import load_all_recipes
 
-        unisolated_packages = []
         recipe_dir = PYODIDE_ROOT / "packages"
         recipes = load_all_recipes(recipe_dir)
         for name, config in recipes.items():
             if config.build.cross_build_env:
-                unisolated_packages.append(name)
+                unisolated_packages[name] = config.package.version
 
     return unisolated_packages
 
 
+def get_cross_build_files_dir(package_name: str) -> Path:
+    """
+    Get the directory containing an unisolated package's cross-build files
+    (such as headers, .a libs, .pxd files, and so on).
+
+    Parameters
+    ----------
+    package_name
+        The name of the package
+
+    Returns
+    -------
+    The directory containing the package's cross-build files, relative to
+    which they should be laid out in site-packages. The directory may not
+    exist if the package has no cross-build files.
+    """
+    PYODIDE_ROOT = get_pyodide_root()
+
+    # TODO: unify libdir for in-tree and out-of-tree builds
+    if in_xbuildenv():
+        libdir = PYODIDE_ROOT / ".." / "site-packages-extras"
+    else:
+        libdir = Path(get_hostsitepackages())
+
+    return libdir / package_name
+
+
 def platform() -> str:
     emscripten_version = get_build_flag("PYODIDE_EMSCRIPTEN_VERSION")
     version = emscripten_version.replace(".", "_")