BLD: use a generator for f2py

This removes all remaining invocations of `py3` in meson.build files.

Not invoking the Python interpreter we're building for at all
helps with cross-compilation, since that interpreter typically
isn't able to run without the use of an emulator like QEMU.

Author: rgommers

mypy.ini

@@ -119,7 +119,7 @@ ignore_missing_imports = True
 [mypy-scipy.optimize._slsqp]
 ignore_missing_imports = True
 
-[mypy-scipy.interpolate.dfitpack]
+[mypy-scipy.interpolate._dfitpack]
 ignore_missing_imports = True
 
 [mypy-scipy.interpolate.interpnd]

scipy/_build_utils/_generate_blas_wrapper.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 Generate wrappers to dispatch BLAS/LAPACK calls to the properly prefixed/
 suffixed symbols.

scipy/_build_utils/echo.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+"""
+A dummy script that only echos its input arguments.
+
+This is useful in case a platform-independent way to run a no-op command
+on a target in a meson.build file is needed (e.g., to establish a
+dependency between targets).
+"""
+import logging
+import sys
+
+logging.debug(f"Passed args to `scipy/_build_utils/echo.py`: {sys.argv[1:]}")

scipy/_build_utils/meson.build

@@ -1,8 +1,8 @@
 if generate_blas_wrappers
-  blas_wrapper_gen = files('_generate_blas_wrapper.py')
+  blas_wrapper_gen = find_program('_generate_blas_wrapper.py')
   blas_lapack_wrappers = custom_target('blas_lapack_wrappers',
       output: ['blas_lapack_wrappers.c'],
-      command: [py3, blas_wrapper_gen, '-o', '@OUTDIR@', accelerate_flag],
+      command: [blas_wrapper_gen, '-o', '@OUTDIR@', accelerate_flag],
       depend_files: [
         '../linalg/cython_blas_signatures.txt',
         '../linalg/cython_lapack_signatures.txt',

scipy/integrate/meson.build

@@ -128,14 +128,8 @@ py3.extension_module('_odepack',
   subdir: 'scipy/integrate'
 )
 
-vode_module = custom_target('vode_module',
-  output: ['_vode-f2pywrappers.f', '_vodemodule.c'],
-  input: 'vode.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_vode',
-  vode_module,
+  f2py_gen.process('vode.pyf'),
   link_with: [vode_lib],
   c_args: [Wno_unused_variable],
   link_args: version_link_args,
@@ -145,14 +139,8 @@ py3.extension_module('_vode',
   subdir: 'scipy/integrate'
 )
 
-lsoda_module = custom_target('lsoda_module',
-  output: ['_lsoda-f2pywrappers.f', '_lsodamodule.c'],
-  input: 'lsoda.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_lsoda',
-  lsoda_module,
+  f2py_gen.process('lsoda.pyf'),
   link_with: [lsoda_lib, mach_lib],
   c_args: [Wno_unused_variable],
   dependencies: [lapack_dep, fortranobject_dep],
@@ -162,14 +150,8 @@ py3.extension_module('_lsoda',
   subdir: 'scipy/integrate'
 )
 
-_dop_module = custom_target('_dop_module',
-  output: ['_dop-f2pywrappers.f', '_dopmodule.c'],
-  input: 'dop.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_dop',
-  _dop_module,
+  f2py_gen.process('dop.pyf'),
   link_with: [dop_lib],
   c_args: [Wno_unused_variable],
   dependencies: [fortranobject_dep],
@@ -186,14 +168,8 @@ py3.extension_module('_test_multivariate',
   subdir: 'scipy/integrate'
 )
 
-_test_odeint_banded_module = custom_target('_test_odeint_banded_module',
-  output: ['_test_odeint_bandedmodule.c', '_test_odeint_banded-f2pywrappers.f'],
-  input: 'tests/banded5x5.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_test_odeint_banded',
-  ['tests/banded5x5.f', _test_odeint_banded_module],
+  ['tests/banded5x5.f', f2py_gen.process('tests/test_odeint_banded.pyf')],
   link_with: [lsoda_lib, mach_lib],
   fortran_args: _fflag_Wno_unused_dummy_argument,
   link_args: version_link_args,

scipy/integrate/tests/banded5x5.pyf renamed to scipy/integrate/tests/test_odeint_banded.pyf

@@ -25,7 +25,7 @@
 import numpy as np
 
 from . import _fitpack_impl
-from . import dfitpack
+from . import _dfitpack as dfitpack
 
 
 dfitpack_int = dfitpack.types.intvar.dtype

scipy/interpolate/_fitpack2.py

@@ -32,7 +32,7 @@
 
 # Try to replace _fitpack interface with
 #  f2py-generated version
-from . import dfitpack
+from . import _dfitpack as dfitpack
 
 
 dfitpack_int = dfitpack.types.intvar.dtype

scipy/interpolate/_fitpack_impl.py

@@ -12,7 +12,7 @@
 from scipy.special import comb
 
 from . import _fitpack_py
-from . import dfitpack
+from . import _dfitpack as dfitpack
 from ._polyint import _Interpolator1D
 from . import _ppoly
 from .interpnd import _ndim_coords_from_arrays

scipy/interpolate/_interpolate.py

@@ -143,15 +143,9 @@ py3.extension_module('_fitpack',
   subdir: 'scipy/interpolate'
 )
 
-dfitpack_module = custom_target('dfitpack_module',
-  output: ['dfitpack-f2pywrappers.f', 'dfitpackmodule.c'],
-  input: 'src/fitpack.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 # TODO: Add flags for 64 bit ints
-py3.extension_module('dfitpack',
-  dfitpack_module,
+py3.extension_module('_dfitpack',
+  f2py_gen.process('src/dfitpack.pyf'),
   c_args: [Wno_unused_variable],
   link_args: version_link_args,
   dependencies: [lapack_dep, fortranobject_dep],

scipy/interpolate/meson.build

@@ -9,7 +9,7 @@
 ! This limit can be overridden with -fmax-stack-var-size, or -frecursive can
 ! be used to force all local arrays to be allocated on the stack.
 !
-python module dfitpack ! in
+python module _dfitpack ! in
 
   usercode '''
 

scipy/interpolate/src/fitpack.pyf renamed to scipy/interpolate/src/dfitpack.pyf

@@ -24,7 +24,7 @@
 # XXX: move to the interpolate namespace
 from scipy.interpolate._ndbspline import make_ndbspl
 
-from scipy.interpolate import dfitpack
+from scipy.interpolate import _dfitpack as dfitpack
 from scipy.interpolate import _bsplines as _b
 
 

scipy/interpolate/tests/test_bsplines.py

@@ -12,7 +12,7 @@
 
 from scipy.interpolate._fitpack_py import (splrep, splev, bisplrep, bisplev,
      sproot, splprep, splint, spalde, splder, splantider, insert, dblint)
-from scipy.interpolate.dfitpack import regrid_smth
+from scipy.interpolate._dfitpack import regrid_smth
 from scipy.interpolate._fitpack2 import dfitpack_int
 
 

scipy/interpolate/tests/test_fitpack.py

@@ -1,12 +1,6 @@
-_test_fortran_module = custom_target('_test_fortran_module',
-  output: ['_test_fortranmodule.c'],
-  input: '_test_fortran.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_test_fortran',
   [
-    _test_fortran_module,
+    f2py_gen.process('test_fortran.pyf'),
     '_test_fortran.f'
   ],
   c_args: [Wno_unused_variable],

scipy/io/meson.build

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 Code generator script to make the Cython BLAS and LAPACK wrappers
 from the files "cython_blas_signatures.txt" and

scipy/io/_test_fortran.pyf renamed to scipy/io/test_fortran.pyf

@@ -3,6 +3,7 @@
 __init__py = fs.copyfile('__init__.py')
 _cy_array_utils_pxd = fs.copyfile('_cythonized_array_utils.pxd')
 
+_generate_pyx = find_program('_generate_pyx.py')
 cython_linalg = custom_target('cython_linalg',
   output: [
     'cython_blas.pyx',
@@ -13,7 +14,7 @@ cython_linalg = custom_target('cython_linalg',
     '_lapack_subroutines.h'
   ],
   input: '_generate_pyx.py',
-  command: [py3, '@INPUT@', '-o', '@OUTDIR@', accelerate_flag],
+  command: [_generate_pyx, '-o', '@OUTDIR@', accelerate_flag],
   depend_files: [
     'cython_blas_signatures.txt',
     'cython_lapack_signatures.txt',
@@ -30,10 +31,11 @@ cython_linalg = custom_target('cython_linalg',
 # warnings about multiple outputs. And using `depends: cython_linalg[2]` does
 # not work, because that generator depends does not accept CustomTargetIndex,
 # only CustomTarget. See https://github.com/mesonbuild/meson/issues/9837
+_echo = find_program('../_build_utils/echo.py')
 cython_blas_pxd = custom_target(
   output: '_dummy_cython_blas.pxd',
   input: cython_linalg[2],
-  command: [py3, '-c', '"@INPUT@"'],
+  command: [_echo, '@INPUT@'],
 )
 
 # pyx -> c, pyx -> cpp generators, depending on __init__.py here.
@@ -109,13 +111,6 @@ py3.extension_module('_flapack',
 
 # TODO: cblas/clapack are built *only* for ATLAS. Why? Is it still needed?
 
-# _interpolative
-interpolative_module = custom_target('interpolative_module',
-  output: '_interpolativemodule.c',
-  input: 'interpolative.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 # id_dist contains a copy of FFTPACK, which has type mismatch warnings
 # that are hard to fix. This code is terrible and noisy during the build,
 # silence it completely.
@@ -159,7 +154,7 @@ py3.extension_module('_interpolative',
     'src/id_dist/src/idzr_rid.f',
     'src/id_dist/src/idzr_rsvd.f',
     'src/id_dist/src/prini.f',
-    interpolative_module,
+    f2py_gen.process('interpolative.pyf'),
   ],
   fortran_args: [fortran_ignore_warnings, _suppress_all_warnings],
   link_args: version_link_args,

scipy/linalg/_generate_pyx.py

@@ -144,6 +144,15 @@ fortranobject_dep = declare_dependency(
   compile_args: _f2py_c_args,
 )
 
+f2py = find_program('f2py')
+# Note: cannot handle .pyf.src or targets with #include's (due to no
+#       `depend_files` - see feature request at meson#8295)
+f2py_gen = generator(generate_f2pymod,
+  arguments : ['@INPUT@', '-o', '@BUILD_DIR@'],
+  output : ['_@[email protected]', '_@[email protected]'],
+)
+
+
 # TODO: 64-bit BLAS and LAPACK
 #
 # Note that this works as long as BLAS and LAPACK are detected properly via
@@ -252,14 +261,15 @@ endif
 
 scipy_dir = py3.get_install_dir() / 'scipy'
 
+version_utils = find_program('../tools/version_utils.py')
 generate_version = custom_target(
   'generate-version',
   install: true,
   build_always_stale: true,
   build_by_default: true,
   output: 'version.py',
   input: '../tools/version_utils.py',
-  command: [py3, '@INPUT@', '--source-root', '@SOURCE_ROOT@'],
+  command: [version_utils, '--source-root', '@SOURCE_ROOT@'],
   install_dir: scipy_dir,
   install_tag: 'python-runtime',
 )

scipy/linalg/meson.build

@@ -92,18 +92,12 @@ py3.extension_module('_zeros',
   subdir: 'scipy/optimize'
 )
 
-lbfgsb_module = custom_target('lbfgsb_module',
-  output: ['_lbfgsb-f2pywrappers.f', '_lbfgsbmodule.c'],
-  input: 'lbfgsb_src/lbfgsb.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_lbfgsb',
   [
     'lbfgsb_src/lbfgsb.f',
     'lbfgsb_src/linpack.f',
     'lbfgsb_src/timer.f',
-    lbfgsb_module,
+    f2py_gen.process('lbfgsb_src/lbfgsb.pyf'),
   ],
   fortran_args: fortran_ignore_warnings,
   link_args: version_link_args,
@@ -126,14 +120,8 @@ py3.extension_module('_moduleTNC',
   subdir: 'scipy/optimize'
 )
 
-cobyla_module = custom_target('cobyla_module',
-  output: ['_cobylamodule.c'],
-  input: 'cobyla/cobyla.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_cobyla',
-  [cobyla_module, 'cobyla/cobyla2.f', 'cobyla/trstlp.f'],
+  [f2py_gen.process('cobyla/cobyla.pyf'), 'cobyla/cobyla2.f', 'cobyla/trstlp.f'],
   c_args: [Wno_unused_variable],
   fortran_args: fortran_ignore_warnings,
   link_args: version_link_args,
@@ -143,14 +131,8 @@ py3.extension_module('_cobyla',
   subdir: 'scipy/optimize'
 )
 
-minpack2_module = custom_target('minpack2_module',
-  output: ['_minpack2module.c'],
-  input: 'minpack2/minpack2.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_minpack2',
-  [minpack2_module, 'minpack2/dcsrch.f', 'minpack2/dcstep.f'],
+  [f2py_gen.process('minpack2/minpack2.pyf'), 'minpack2/dcsrch.f', 'minpack2/dcstep.f'],
   fortran_args: fortran_ignore_warnings,
   link_args: version_link_args,
   dependencies: [fortranobject_dep],
@@ -160,14 +142,8 @@ py3.extension_module('_minpack2',
   subdir: 'scipy/optimize'
 )
 
-slsqp_module = custom_target('slsqp_module',
-  output: ['_slsqpmodule.c'],
-  input: 'slsqp/slsqp.pyf',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-)
-
 py3.extension_module('_slsqp',
-  [slsqp_module, 'slsqp/slsqp_optmz.f'],
+  [f2py_gen.process('slsqp/slsqp.pyf'), 'slsqp/slsqp_optmz.f'],
   fortran_args: fortran_ignore_warnings,
   link_args: version_link_args,
   dependencies: [fortranobject_dep],

scipy/meson.build

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 python generate_sparsetools.py
 

scipy/optimize/meson.build

@@ -97,14 +97,8 @@ foreach ele: elements
     gnu_symbol_visibility: 'hidden',
   )
 
-  propack_module = custom_target('propack_module' + ele[0],
-    output: [ele[0] + '-f2pywrappers.f', ele[0] + 'module.c'],
-    input: ele[2],
-    command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@']
-  )
-
   propacklib = py3.extension_module(ele[0],
-    propack_module,
+    f2py_gen.process(ele[2]),
     link_with: propack_lib,
     c_args: ['-U_OPENMP', _cpp_Wno_cpp],
     fortran_args: _fflag_Wno_maybe_uninitialized,

scipy/sparse/_generate_sparsetools.py

@@ -1,3 +1,4 @@
+gen_sparsetools = find_program('../_generate_sparsetools.py')
 _sparsetools_headers = custom_target('_sparsetools_headers',
   output: [
     'bsr_impl.h',
@@ -7,7 +8,7 @@ _sparsetools_headers = custom_target('_sparsetools_headers',
     'sparsetools_impl.h',
   ],
   input: '../_generate_sparsetools.py',
-  command: [py3, '@INPUT@', '--no-force', '-o', '@OUTDIR@']
+  command: [gen_sparsetools, '--no-force', '-o', '@OUTDIR@']
 )
 
 py3.extension_module('_sparsetools',

scipy/sparse/linalg/_propack/meson.build

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 python _generate_pyx.py