The infinite loop was the correct idea (I guess)
(at least I reproduce the bug when setting my pythonpath that way)

The easiest is likely to change your pythonpath, or you can use the following patch:

Cheers,

Olivier

=== modified file 'models/__init__.py'
--- models/__init__.py	2021-01-29 22:04:24 +0000
+++ models/__init__.py	2021-03-29 21:23:51 +0000
@@ -47,6 +47,8 @@
             pass
         if 'PYTHONPATH' in os.environ:
             for p in os.environ['PYTHONPATH'].split(':'):
+                if not p:
+                    continue
                 new_name = os.path.join(p, name)
                 try:
                     return load_model(new_name, decay)



> On 29 Mar 2021, at 23:19, Olivier Mattelaer <email address hidden> wrote:
> 
> Hi,
> 
> I do not reproduce the problem, but it is likely related to your enviroment and more specifically to the value of the PYTHONPATH variable.
> Could you do echo $PYTHONPATH to see how long that variable is?
> 
> One potential issue is if you have :: in that variable then it is not
> impossible to trigger an infinite loop. Would that be the case?
> 
> Cheers,
> 
> Olivier
> 
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1921787
> 
> Title:
>  issue with recursive call to model load
> 
> Status in MadGraph5_aMC@NLO:
>  New
> 
> Bug description:
>  Dear MadGraph,
> 
>  This is a follow-up to
>  https://answers.launchpad.net/mg5amcnlo/+question/696199
> 
>  As mentioned earlier,  have taken the heavyN FeynRules model and added
>  a dim-5 dipole operator. In MadGraph v2.7.3, I can execute the
>  following command without a problem:
> 
>  import model heavyNeff4_UFO --modelname
>  generate n5 > all all
>  output Test1
> 
>  I then go to Test1 and run MadEvent, executing calculate_decay_widths
>  . The code works, and I get a result.
> 
>  If I do the same in MadGraph v2.9.2, there is a problem when executing
>  "output Test1", with MadGraph crashing:
> 
>  MG5_aMC>output Test1
>  INFO: initialize a new directory: Test1 
>  INFO: remove old information in Test1 
>  INFO: Generating Helas calls for process: n5 > ve z QNP<=2 @1 
>  INFO: Processing color information for process: n5 > ve z QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > vm z QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > vm z QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > vt z QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > vt z QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > a ve QNP<=2 @1 
>  INFO: Processing color information for process: n5 > a ve QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > a vm QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > a vm QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > a vt QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > a vt QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > a n4 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > a n4 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > a n6 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > a n6 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > ve h QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > ve h QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > vm h QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > vm h QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > vt h QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > vt h QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > e- w+ QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > e- w+ QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > mu- w+ QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > mu- w+ QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > ta- w+ QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > ta- w+ QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > e+ w- QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > e+ w- QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > mu+ w- QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > mu+ w- QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > ta+ w- QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > ta+ w- QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > z n4 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > z n4 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > z n6 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > z n6 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > h n4 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > h n4 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > h n5 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > h n5 QNP<=2 @1 
>  INFO: Generating Helas calls for process: n5 > h n6 QNP<=2 @1 
>  INFO: Reusing existing color information for process: n5 > h n6 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_vez 
>  INFO: Generating Feynman diagrams for Process: n5 > ve z QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_vmz 
>  INFO: Generating Feynman diagrams for Process: n5 > vm z QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_vtz 
>  INFO: Generating Feynman diagrams for Process: n5 > vt z QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_ave 
>  INFO: Generating Feynman diagrams for Process: n5 > a ve QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_avm 
>  INFO: Generating Feynman diagrams for Process: n5 > a vm QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_avt 
>  INFO: Generating Feynman diagrams for Process: n5 > a vt QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_an4 
>  INFO: Generating Feynman diagrams for Process: n5 > a n4 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_an6 
>  INFO: Generating Feynman diagrams for Process: n5 > a n6 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_veh 
>  INFO: Generating Feynman diagrams for Process: n5 > ve h QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_vmh 
>  INFO: Generating Feynman diagrams for Process: n5 > vm h QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_vth 
>  INFO: Generating Feynman diagrams for Process: n5 > vt h QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_emwp 
>  INFO: Generating Feynman diagrams for Process: n5 > e- w+ QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_mumwp 
>  INFO: Generating Feynman diagrams for Process: n5 > mu- w+ QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_tamwp 
>  INFO: Generating Feynman diagrams for Process: n5 > ta- w+ QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_epwm 
>  INFO: Generating Feynman diagrams for Process: n5 > e+ w- QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_mupwm 
>  INFO: Generating Feynman diagrams for Process: n5 > mu+ w- QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_tapwm 
>  INFO: Generating Feynman diagrams for Process: n5 > ta+ w- QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_zn4 
>  INFO: Generating Feynman diagrams for Process: n5 > z n4 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_zn6 
>  INFO: Generating Feynman diagrams for Process: n5 > z n6 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_hn4 
>  INFO: Generating Feynman diagrams for Process: n5 > h n4 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_hn5 
>  INFO: Generating Feynman diagrams for Process: n5 > h n5 QNP<=2 @1 
>  INFO: Creating files in directory P1_n5_hn6 
>  INFO: Generating Feynman diagrams for Process: n5 > h n6 QNP<=2 @1 
>  Generated helas calls for 22 subprocesses (25 diagrams) in 0.023 s
>  Wrote files for 91 helas calls in 0.399 s
>  Fatal Python error: _Py_CheckRecursiveCall: Cannot recover from stack overflow.
>  Python runtime state: initialized
> 
>  Thread 0x00007f3fc67d5640 (most recent call first):
>    File "/usr/lib64/python3.9/threading.py", line 312 in wait
>    File "/usr/lib64/python3.9/queue.py", line 171 in get
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/madgraph/various/cluster.py", line 631 in worker
>    File "/usr/lib64/python3.9/threading.py", line 892 in run
>    File "/usr/lib64/python3.9/threading.py", line 954 in _bootstrap_inner
>    File "/usr/lib64/python3.9/threading.py", line 912 in _bootstrap
> 
>  Current thread 0x00007f3fd4e47740 (most recent call first):
>    File "<frozen importlib._bootstrap_external>", line 64 in <listcomp>
>    File "<frozen importlib._bootstrap_external>", line 64 in _path_join
>    File "<frozen importlib._bootstrap_external>", line 369 in cache_from_source
>    File "<frozen importlib._bootstrap_external>", line 434 in _get_cached
>    File "<frozen importlib._bootstrap>", line 391 in cached
>    File "<frozen importlib._bootstrap>", line 550 in _init_module_attrs
>    File "<frozen importlib._bootstrap>", line 571 in module_from_spec
>    File "<frozen importlib._bootstrap>", line 666 in _load_unlocked
>    File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
>    File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/heavyNeff4/particles.py", line 10 in <module>
>    File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
>    File "<frozen importlib._bootstrap_external>", line 790 in exec_module
>    File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
>    File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
>    File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/heavyNeff4/__init__.py", line 3 in <module>
>    File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
>    File "<frozen importlib._bootstrap_external>", line 790 in exec_module
>    File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
>    File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
>    File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 44 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    File "/home/jjones/Programs/MG5_aMC_v2_9_2/models/__init__.py", line 52 in load_model
>    ...
>  [jjones@arrakis MG5_aMC_v2_9_2]$
> 
>  Any clues to what might be happening?
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1921787/+subscriptions