BUG: Fix meson build failure due to unchanged inplace auto-generated …

…dispatch config headers

  Ensure that the distutils generated config files and wrapped sources,
  derived from dispatch-able sources are consistently generated within the build directory
  when the inplace build option is enabled.

  This change is crucial to prevent conflicts with meson-generated config headers.
  Given that `spin build --clean` does not remove these headers, which
  requires cleaning up the numpy root via `git clean` otherwise
  the build will fails.

.gitignore

@@ -208,11 +208,6 @@ tools/swig/test/Array.py
 
 # SIMD generated files #
 ###################################
-# config headers of dispatchable sources
-*.dispatch.h
-# wrapped sources of dispatched targets, e.g. *.dispatch.avx2.c
-*.dispatch.*.c
-*.dispatch.*.cpp
 # _simd module
 numpy/core/src/_simd/_simd.dispatch.c
 numpy/core/src/_simd/_simd_data.inc

numpy/distutils/command/build_clib.py

@@ -320,8 +320,8 @@ def build_a_library(self, build_info, lib_name, libraries):
             dispatch_hpath = os.path.join("numpy", "distutils", "include")
             dispatch_hpath = os.path.join(bsrc_dir, dispatch_hpath)
             include_dirs.append(dispatch_hpath)
-
-            copt_build_src = None if self.inplace else bsrc_dir
+            # copt_build_src = None if self.inplace else bsrc_dir
+            copt_build_src = bsrc_dir
             for _srcs, _dst, _ext in (
                 ((c_sources,), copt_c_sources, ('.dispatch.c',)),
                 ((c_sources, cxx_sources), copt_cxx_sources,

numpy/distutils/command/build_ext.py

@@ -458,7 +458,16 @@ def build_extension(self, ext):
             dispatch_hpath = os.path.join(bsrc_dir, dispatch_hpath)
             include_dirs.append(dispatch_hpath)
 
-            copt_build_src = None if self.inplace else bsrc_dir
+            # copt_build_src = None if self.inplace else bsrc_dir
+            # Always generate the generated config files and dispatch-able sources
+            # inside the build directory, even if the build option `inplace` is enabled.
+            # This approach prevents conflicts with Meson-generated config headers.
+            # Since `spin build --clean` will not remove these headers,
+            # they might overwrite the generated Meson headers, causing compatibility issues.
+            # Maintaining separate directories ensures compatibility between
+            # distutils dispatch config headers and Meson headers, avoiding build disruptions.
+            # See gh-24450 for more details.
+            copt_build_src = bsrc_dir
             for _srcs, _dst, _ext in (
                 ((c_sources,), copt_c_sources, ('.dispatch.c',)),
                 ((c_sources, cxx_sources), copt_cxx_sources,