Describe the issue:

I'm trying to compile a fix-form Fortran file with f2py. In the past I have had this working, but apparently some recent change has broken this? Or perhaps I'm doing something wrong.

I'm including a very simple test file on which it is also failing. I'm getting the same type of error on a much larger file. It seems to me like it doesn't like the fix-form spacing or something, but the file hasn't changed since I previously had it working with f2py.

Reproduce the code example:

Example Fortran File where I'm having the issue:

TEST.f

      subroutine test ()

      implicit none

      character(8) name
      name = 'TEST'

      return
      end

Then running:

f2py -h TEST.pyf TEST.f -m TEST --overwrite-signature --verbose

My actual program is an Abaqus UMAT, so it also only implements subroutines and no main.

Error message:

Reading fortran codes...
	Reading file 'TEST.f' (format:fix,strict)
analyzeline: Creating module block 'TEST'
analyzeline: Creating additional interface block (groupcounter=2).
Line #7 in TEST.f:"      name = 'TEST' "
	crackline:3: No pattern for line
Line #8 in TEST.f:"      return "
	crackline:3: No pattern for line
Post-processing...
	Block: TEST
			Block: test
In: :TEST:TEST.f:test
buildimplicitrules: no implicit rules for routine 'test'.
In: :TEST:TEST.f:test
buildimplicitrules: no implicit rules for routine 'test'.
Applying post-processing hooks...
  character_backward_compatibility_hook
Post-processing (stage 2)...
Saving signatures to file "./TEST.pyf"
Stopping. Edit the signature file and then run f2py on the signature file: f2py ./TEST.pyf

Python and NumPy Versions:

2.2.4
3.13.0 (main, Oct 16 2024, 03:23:02) [Clang 18.1.8 ]

Runtime Environment:

[{'numpy_version': '2.2.4',
'python': '3.13.0 (main, Oct 16 2024, 03:23:02) [Clang 18.1.8 ]',
'uname': uname_result(system='Linux', node='clarklaptop', release='6.14.2-arch1-1', version='#1 SMP PREEMPT_DYNAMIC Thu, 10 Apr 2025 18:43:59 +0000', machine='x86_64')},
{'simd_extensions': {'baseline': ['SSE', 'SSE2', 'SSE3'],
'found': ['SSSE3',
'SSE41',
'POPCNT',
'SSE42',
'AVX',
'F16C',
'FMA3',
'AVX2',
'AVX512F',
'AVX512CD',
'AVX512_SKX',
'AVX512_CLX',
'AVX512_CNL',
'AVX512_ICL'],
'not_found': ['AVX512_KNL', 'AVX512_KNM']}},
{'architecture': 'SkylakeX',
'filepath': '/home/clark/Research/SinglePointSimulator/.venv/lib/python3.13/site-packages/numpy.libs/libscipy_openblas64_-6bb31eeb.so',
'internal_api': 'openblas',
'num_threads': 16,
'prefix': 'libscipy_openblas',
'threading_layer': 'pthreads',
'user_api': 'blas',
'version': '0.3.28'}]

Context for the issue:

I think it's very possible that I'm just formatting something incorrectly, but I need a second set of eyes to look at this. I have run into a similar issue before, but I was using non-standard Fortran extensions, and now I have fixed that issue, but this seems to persist.

Happy to include a longer traceback of what's failing with my actual script, but it's the same "crackline:3; No pattern for line"

TIA for any and all help!