numpy · DWesl · Jun 27, 2025 · Jun 27, 2025 · Jun 27, 2025 · Jun 27, 2025
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
@@ -56,6 +56,9 @@ stages:
         python tools/linter.py
       displayName: 'Run Lint Checks'
       failOnStderr: true
+    - script: |
+        python tools/check_python_h_first.py
+      displayName: 'Check Python.h is first file included'
 
   - job: Linux_Python_311_32bit_full_with_asserts
     pool:

diff --git a/numpy/_core/src/common/binop_override.h b/numpy/_core/src/common/binop_override.h
@@ -1,8 +1,8 @@
 #ifndef NUMPY_CORE_SRC_COMMON_BINOP_OVERRIDE_H_
 #define NUMPY_CORE_SRC_COMMON_BINOP_OVERRIDE_H_
 
-#include <string.h>
 #include <Python.h>
+#include <string.h>
 #include "numpy/arrayobject.h"
 
 #include "get_attr_string.h"

diff --git a/numpy/_core/src/common/blas_utils.c b/numpy/_core/src/common/blas_utils.c
@@ -1,3 +1,7 @@
+#include "numpy/npy_math.h"     // npy_get_floatstatus_barrier
+#include "numpy/numpyconfig.h"  // NPY_VISIBILITY_HIDDEN
+#include "blas_utils.h"
+
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -6,10 +10,6 @@
 #include <sys/sysctl.h>
 #endif
 
-#include "numpy/numpyconfig.h"  // NPY_VISIBILITY_HIDDEN
-#include "numpy/npy_math.h"     // npy_get_floatstatus_barrier
-#include "blas_utils.h"
-
 #if NPY_BLAS_CHECK_FPE_SUPPORT
 
 /* Return whether we're running on macOS 15.4 or later

diff --git a/numpy/_core/src/common/blas_utils.h b/numpy/_core/src/common/blas_utils.h
@@ -1,7 +1,7 @@
-#include <stdbool.h>
-
 #include "numpy/numpyconfig.h" // for NPY_VISIBILITY_HIDDEN
 
+#include <stdbool.h>
+
 /* NPY_BLAS_CHECK_FPE_SUPPORT controls whether we need a runtime check
  * for floating-point error (FPE) support in BLAS.
  */

diff --git a/numpy/_core/src/multiarray/array_method.c b/numpy/_core/src/multiarray/array_method.c
@@ -30,8 +30,8 @@
 #define _UMATHMODULE
 #define _MULTIARRAYMODULE
 
-#include <npy_pycompat.h>
 #include <numpy/ndarrayobject.h>
+#include <npy_pycompat.h>
 #include "arrayobject.h"
 #include "array_coercion.h"
 #include "array_method.h"

diff --git a/numpy/_core/src/multiarray/common.h b/numpy/_core/src/multiarray/common.h
@@ -1,6 +1,8 @@
 #ifndef NUMPY_CORE_SRC_MULTIARRAY_COMMON_H_
 #define NUMPY_CORE_SRC_MULTIARRAY_COMMON_H_
 
+#include <Python.h>
+
 #include <structmember.h>
 #include "numpy/npy_common.h"
 #include "numpy/ndarraytypes.h"

diff --git a/numpy/_core/src/multiarray/textreading/conversions.h b/numpy/_core/src/multiarray/textreading/conversions.h
@@ -1,12 +1,12 @@
 #ifndef NUMPY_CORE_SRC_MULTIARRAY_TEXTREADING_CONVERSIONS_H_
 #define NUMPY_CORE_SRC_MULTIARRAY_TEXTREADING_CONVERSIONS_H_
 
-#include <stdbool.h>
-
 #define NPY_NO_DEPRECATED_API NPY_API_VERSION
 #define _MULTIARRAYMODULE
 #include "numpy/arrayobject.h"
 
+#include <stdbool.h>
+
 #include "textreading/parser_config.h"
 
 NPY_NO_EXPORT int

diff --git a/numpy/_core/src/npysort/npysort_common.h b/numpy/_core/src/npysort/npysort_common.h
@@ -1,8 +1,8 @@
 #ifndef __NPY_SORT_COMMON_H__
 #define __NPY_SORT_COMMON_H__
 
-#include <stdlib.h>
 #include <numpy/ndarraytypes.h>
+#include <stdlib.h>
 #include <numpy/npy_math.h>
 #include "dtypemeta.h"
 

diff --git a/numpy/_core/src/umath/clip.cpp b/numpy/_core/src/umath/clip.cpp
@@ -1,7 +1,6 @@
 /**
  * This module provides the inner loops for the clip ufunc
  */
-#include <type_traits>
 
 #define _UMATHMODULE
 #define _MULTIARRAYMODULE
@@ -10,6 +9,7 @@
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 
+#include <type_traits>
 #include "numpy/halffloat.h"
 #include "numpy/ndarraytypes.h"
 #include "numpy/npy_common.h"

diff --git a/numpy/random/src/mt19937/randomkit.c b/numpy/random/src/mt19937/randomkit.c
@@ -62,6 +62,8 @@
  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#include <Python.h>
+
 /* static char const rcsid[] =
   "@(#) $Jeannot: randomkit.c,v 1.28 2005/07/21 22:14:09 js Exp $"; */
 

diff --git a/tools/check_python_h_first.py b/tools/check_python_h_first.py
@@ -0,0 +1,254 @@
+#!/usr/bin/env python
+"""Check that Python.h is included before any stdlib headers.
+
+May be a bit overzealous, but it should get the job done.
+"""
+import argparse
+import fnmatch
+import os.path
+import re
+import subprocess
+import sys
+
+from get_submodule_paths import get_submodule_paths
+
+HEADER_PATTERN = re.compile(
+    r'^\s*#\s*include\s*[<"]((?:\w+/)*\w+(?:\.h[hp+]{0,2})?)[>"]\s*$'
+)
+
+PYTHON_INCLUDING_HEADERS = [
+    "Python.h",
+    # This isn't all of Python.h, but it is the visibility macros
+    "pyconfig.h",
+    "numpy/npy_common.h",
+    "numpy/npy_math.h",
+    "numpy/arrayobject.h",
+    "numpy/ndarrayobject.h",
+    "numpy/ndarraytypes.h",
+    "numpy/random/distributions.h",
+    "npy_sort.h",
+    "npy_config.h",
+    "common.h",
+    "npy_cpu_features.h",
+    # Boost::Python
+    "boost/python.hpp",
+]
+LEAF_HEADERS = [
+    "numpy/numpyconfig.h",
+    "numpy/npy_os.h",
+    "numpy/npy_cpu.h",
+    "numpy/utils.h",
+]
+
+C_CPP_EXTENSIONS = (".c", ".h", ".cpp", ".hpp", ".cc", ".hh", ".cxx", ".hxx")
+# check against list in diff_files
+
+PARSER = argparse.ArgumentParser(description=__doc__)
+PARSER.add_argument(
+    "files",
+    nargs="*",
+    help="Lint these files or directories; use **/*.c to lint all files\n"
+    "Expects relative paths",
+)
+
+
+def check_python_h_included_first(name_to_check: str) -> int:
+    """Check that the passed file includes Python.h first if it does at all.
+
+    Perhaps overzealous, but that should work around concerns with
+    recursion.
+
+    Parameters
+    ----------
+    name_to_check : str
+        The name of the file to check.
+
+    Returns
+    -------
+    int
+        The number of headers before Python.h
+    """
+    included_python = False
+    included_non_python_header = []
+    warned_python_construct = False
+    basename_to_check = os.path.basename(name_to_check)
+    in_comment = False
+    includes_headers = False
+    with open(name_to_check) as in_file:
+        for i, line in enumerate(in_file, 1):
+            # Very basic comment parsing
+            # Assumes /*...*/ comments are on their own lines
+            if "/*" in line:
+                if "*/" not in line:
+                    in_comment = True
+                # else-branch could use regex to remove comment and continue
+                continue
+            if in_comment:
+                if "*/" in line:
+                    in_comment = False
+                continue
+            line = line.split("//", 1)[0].strip()
+            match = HEADER_PATTERN.match(line)
+            if match:
+                includes_headers = True
+                this_header = match.group(1)
+                if this_header in PYTHON_INCLUDING_HEADERS:
+                    if included_non_python_header and not included_python:
+                        # Headers before python-including header
+                        print(
+                            f"Header before Python.h in file {name_to_check:s}\n"
+                            f"Python.h on line {i:d}, other header(s) on line(s)"
+                            f" {included_non_python_header}",
+                            file=sys.stderr,
+                        )
+                    # else:  # no headers before python-including header
+                    included_python = True
+                    PYTHON_INCLUDING_HEADERS.append(basename_to_check)
+                    if os.path.dirname(name_to_check).endswith("include/numpy"):
+                        PYTHON_INCLUDING_HEADERS.append(f"numpy/{basename_to_check:s}")
+                    # We just found out where Python.h comes in this file
+                    break
+                elif this_header in LEAF_HEADERS:
+                    # This header is just defines, so it won't include
+                    # the system headers that cause problems
+                    continue
+                elif not included_python and (
+                    "numpy/" in this_header
+                    and this_header not in LEAF_HEADERS
+                    or "python" in this_header.lower()
+                ):
+                    print(
+                        f"Python.h not included before python-including header "
+                        f"in file {name_to_check:s}\n"
+                        f"{this_header:s} on line {i:d}",
+                        file=sys.stderr,
+                    )
+                    included_python = True
+                    PYTHON_INCLUDING_HEADERS.append(basename_to_check)
+                elif not included_python and this_header not in LEAF_HEADERS:
+                    included_non_python_header.append(i)
+            elif (
+                not included_python
+                and not warned_python_construct
+                and ".h" not in basename_to_check
+            ) and ("py::" in line or "PYBIND11_" in line):
+                print(
+                    "Python-including header not used before python constructs "
+                    f"in file {name_to_check:s}\nConstruct on line {i:d}",
+                    file=sys.stderr,
+                )
+                warned_python_construct = True
+    if not includes_headers:
+        LEAF_HEADERS.append(basename_to_check)
+    return included_python and len(included_non_python_header)
+
+
+def sort_order(path: str) -> tuple[int, str]:
+    if "include/numpy" in path:
+        # Want to process numpy/*.h first, to work out which of those
+        # include Python.h directly
+        priority = 0x00
+    elif "h" in os.path.splitext(path)[1].lower():
+        # Then other headers, which tend to include numpy/*.h
+        priority = 0x10
+    else:
+        # Source files after headers, to give the best chance of
+        # properly checking whether they include Python.h
+        priority = 0x20
+    if "common" in path:
+        priority -= 8
+    path_basename = os.path.basename(path)
+    if path_basename.startswith("npy_"):
+        priority -= 4
+    elif path_basename.startswith("npy"):
+        priority -= 3
+    elif path_basename.startswith("np"):
+        priority -= 2
+    if "config" in path_basename:
+        priority -= 1
+    return priority, path
+
+
+def process_files(file_list: list[str]) -> int:
+    n_out_of_order = 0
+    submodule_paths = get_submodule_paths()
+    root_directory = os.path.dirname(os.path.dirname(__file__))
+    for name_to_check in sorted(file_list, key=sort_order):
+        name_to_check = os.path.join(root_directory, name_to_check)
+        if any(submodule_path in name_to_check for submodule_path in submodule_paths):
+            continue
+        if ".dispatch." in name_to_check:
+            continue
+        try:
+            n_out_of_order += check_python_h_included_first(name_to_check)
+        except UnicodeDecodeError:
+            print(f"File {name_to_check:s} not utf-8", sys.stdout)
+    return n_out_of_order
+
+
+def find_c_cpp_files(root: str) -> list[str]:
+
+    result = []
+
+    for dirpath, dirnames, filenames in os.walk(root):
+        # I'm assuming other people have checked boost
+        for name in ("build", ".git", "boost"):
+            try:
+                dirnames.remove(name)
+            except ValueError:
+                pass
+        for name in fnmatch.filter(dirnames, "*.p"):
+            dirnames.remove(name)
+        result.extend(
+            [
+                os.path.join(dirpath, name)
+                for name in filenames
+                if os.path.splitext(name)[1].lower() in C_CPP_EXTENSIONS
+            ]
+        )
+    # Check the headers before the source files
+    result.sort(key=lambda path: "h" in os.path.splitext(path)[1], reverse=True)
+    return result
+
+
+def diff_files(sha: str) -> list[str]:
+    """Find the diff since the given SHA.
+
+    Adapted from lint.py
+    """
+    res = subprocess.run(
+        [
+            "git",
+            "diff",
+            "--name-only",
+            "--diff-filter=ACMR",
+            "-z",
+            sha,
+            "--",
+            # Check against C_CPP_EXTENSIONS
+            "*.[chCH]",
+            "*.[ch]pp",
+            "*.[ch]xx",
+            "*.cc",
+            "*.hh",
+        ],
+        stdout=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    res.check_returncode()
+    return [f for f in res.stdout.split("\0") if f]
+
+
+if __name__ == "__main__":
+    args = PARSER.parse_args()
+
+    if len(args.files) == 0:
+        files = find_c_cpp_files("numpy")
+    else:
+        files = args.files
+        if len(files) == 1 and os.path.isdir(files[0]):
+            files = find_c_cpp_files(files[0])
+
+    # See which of the headers include Python.h and add them to the list
+    n_out_of_order = process_files(files)
+    sys.exit(n_out_of_order)