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mrwizard82d1 opened this issue Feb 9, 2022 · 3 comments
Closed

Still cannot create Nullable<T>(None) #1693

mrwizard82d1 opened this issue Feb 9, 2022 · 3 comments

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@mrwizard82d1
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mrwizard82d1 commented Feb 9, 2022 •
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Environment

  • Pythonnet version: 2.5.2
  • Python version: 3.8.7
  • Operating System: Windows 10
  • .NET Runtime:
    Runtime Environment:
    OS Name: Windows
    OS Version: 10.0.19044
    OS Platform: Windows
    RID: win10-x64
    Base Path: C:\Program Files\dotnet\sdk\6.0.101\

Details

  • Describe what you were trying to get done.

I was trying to invoke a C# function with an argument of type Nullable. Python.NET reported that it could find no function matching the arguments. Eventually, I tried to test the fix for issue #460.

Python 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.28.0 -- An enhanced Interactive Python. Type '?' for help.

[ins] In [1]: import clr

[ins] In [2]: from System import (UInt32, Nullable)

[ins] In [3]: Nullable[UInt32](3)
Out[3]: <System.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] object at 0x0000020A6AF106D0>

[ins] In [4]: Nullable[UInt32](None)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-4-b1659b301f87> in <module>
----> 1 Nullable[UInt32](None)

TypeError: No constructor matches given arguments: (<class 'NoneType'>)
  • If there was a crash, please include the traceback here.

I also tried testing against pythonnet 3.0.0.a2. I see the following stack trace.

Python 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)]                                                             
Type 'copyright', 'credits' or 'license' for more information                                                                                     
IPython 8.0.1 -- An enhanced Interactive Python. Type '?' for help.                                                                               
                                                                                                                                                  
[ins] In [1]: import clr                                                                                                                          
                                                                                                                                                  
[ins] In [2]: from System import DateTime, Double, Guid, Nullable, String, UInt32                                                                 
                                                                                                                                                  
[ins] In [3]: Nullable[Double](None)                                                                                                              
Python.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                                             
                                                                                                                                                  
                                                                                                                                                  
The above exception was the direct cause of the following exception:                                                                              
                                                                                                                                                  
System.ArgumentException: 'NoneType' value cannot be converted to System.Double in method Void .ctor(Double) ---> Python.Runtime.PythonException: 
'NoneType' value cannot be converted to System.Double                                                                                             
                                                                                                                                                  
   --- End of inner exception stack trace ---                                                                                                     
                                                                                                                                                  
The above exception was the direct cause of the following exception:                                                                              
                                                                                                                                                  
System.AggregateException: One or more errors occurred. ---> System.ArgumentException: 'NoneType' value cannot be converted to System.Double in me
thod Void .ctor(Double) ---> Python.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                
                                                                                                                                                  
                                                                                                                                                  
   --- End of inner exception stack trace ---                                                                                                     
   --- End of inner exception stack trace ---                                                                                                     
---> (Inner Exception #0) System.ArgumentException: 'NoneType' value cannot be converted to System.Double in method Void .ctor(Double) ---> Python
.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                                                   
                                                                                                                                                  
   --- End of inner exception stack trace ---<---                                                                                                 
                                                                                                                                                  
                                                                                                                                                  
The above exception was the direct cause of the following exception:                                                                              
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 3251, in run_code                                                                                                                              
                                                                                                                                                  
    exec(code_obj, self.user_global_ns, self.user_ns)                                                                                             
  File "<ipython-input-3-3b78c20f70fb>", line 1, in <module>                                                                                      
    Nullable[Double](None)                                                                                                                        
TypeError: No constructor matches given arguments: (<class 'NoneType'>)                                                                           
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1934, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = value._render_traceback_()                                                                                                              
AttributeError: 'TypeError' object has no attribute '_render_traceback_'                                                                          
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 3191, in run_ast_nodes                                                                                                                         
                                                                                                                                                  
    if await self.run_code(code, result, async_=asy):                                                                                             
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 3268, in run_code                                                                                                                              
                                                                                                                                                  
    self.showtraceback(running_compiled_code=True)                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1936, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 1105, 
in structured_traceback                                                                                                                           
                                                                                                                                                  
    return FormattedTB.structured_traceback(                                                                                                      
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 999, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    return VerboseTB.structured_traceback(                                                                                                        
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 871, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                
                                                                                                                                                  
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 775, i
n format_exception_as_a_whole                                                                                                                     
                                                                                                                                                  
    assert etb is not None                                                                                                                        
AssertionError                                                                                                                                    
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1934, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = value._render_traceback_()                                                                                                              
AttributeError: 'AssertionError' object has no attribute '_render_traceback_'                                                                     
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 2814, in _run_cell                                                                                                                             
                                                                                                                                                  
    return runner(coro)                                                                                                                           
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\async_helpers.py", line 
129, in _pseudo_sync_runner                                                                                                                       
                                                                                                                                                  
    coro.send(None)                                                                                                                               
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 3012, in run_cell_async                                                                                                                        
                                                                                                                                                  
    has_raised = await self.run_ast_nodes(code_ast.body, cell_name,                                                                               
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 3210, in run_ast_nodes                                                                                                                         
                                                                                                                                                  
    self.showtraceback()                                                                                                                          
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1936, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 1105, 
in structured_traceback                                                                                                                           
                                                                                                                                                  
    return FormattedTB.structured_traceback(                                                                                                      
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 999, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    return VerboseTB.structured_traceback(                                                                                                        
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 871, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                
                                                                                                                                                  
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 775, i
n format_exception_as_a_whole                                                                                                                     
                                                                                                                                                  
    assert etb is not None                                                                                                                        
AssertionError                                                                                                                                    
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1934, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = value._render_traceback_()                                                                                                              
AttributeError: 'AssertionError' object has no attribute '_render_traceback_'                                                                     
                                                                                                                                                  
During handling of the above exception, another exception occurred:                                                                               
                                                                                                                                                  
Traceback (most recent call last):                                                                                                                
  File "C:\Users\larry.jones\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 194, in _run_module_as_main                               
                                                                                                                                                  
    return _run_code(code, main_globals, None,                                                                                                    
  File "C:\Users\larry.jones\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 87, in _run_code                                          
                                                                                                                                                  
    exec(code, run_globals)                                                                                                                       
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\Scripts\ipython.exe\__main__.py", line 7, in <module>  
                                                                                                                                                  
    sys.exit(start_ipython())                                                                                                                     
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\__init__.py", line 123, in st
art_ipython                                                                                                                                       
    return launch_new_instance(argv=argv, **kwargs)                                                                                               
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\traitlets\config\application.py", lin
e 846, in launch_instance                                                                                                                         
                                                                                                                                                  
    app.start()                                                                                                                                   
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\terminal\ipapp.py", line 316,
 in start                                                                                                                                         
    self.shell.mainloop()                                                                                                                         
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\terminal\interactiveshell.py"
, line 611, in mainloop                                                                                                                           
                                                                                                                                                  
    self.interact()                                                                                                                               
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\terminal\interactiveshell.py"
, line 604, in interact                                                                                                                           
                                                                                                                                                  
    self.run_cell(code, store_history=True)                                                                                                       
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 2768, in run_cell                                                                                                                              
                                                                                                                                                  
    result = self._run_cell(                                                                                                                      
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 2819, in _run_cell                                                                                                                             
                                                                                                                                                  
    self.showtraceback(running_compiled_code=True)                                                                                                
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\interactiveshell.py", li
ne 1936, in showtraceback                                                                                                                         
                                                                                                                                                  
    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 1105, 
in structured_traceback                                                                                                                           
                                                                                                                                                  
    return FormattedTB.structured_traceback(                                                                                                      
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 999, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    return VerboseTB.structured_traceback(                                                                                                        
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 871, i
n structured_traceback                                                                                                                            
                                                                                                                                                  
    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                
                                                                                                                                                  
  File "C:\Users\larry.jones\AppData\Local\pypoetry\Cache\virtualenvs\libpy-QVeQv1xn-py3.8\lib\site-packages\IPython\core\ultratb.py", line 775, i
n format_exception_as_a_whole                                                                                                                     
                                                                                                                                                  
    assert etb is not None                                                                                                                        
AssertionError                                                                                                                                    
                                                                                                                                                  
If you suspect this is an IPython 8.0.1 bug, please report it at:                                                                                 
    https://github.com/ipython/ipython/issues                                                                                                     
or send an email to the mailing list at ipython-dev@python.org                                                                                    
                                                                                                                                                  
You can print a more detailed traceback right now with "%tb", or use "%debug"                                                                     
to interactively debug it.                                                                                                                        
                                                                                                                                                  
Extra-detailed tracebacks for bug-reporting purposes can be enabled via:                                                                          
    %config Application.verbose_crash=True
@lostmsu
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lostmsu commented Feb 9, 2022

Why do you need an instance of Nullable<T> with value null? Why can't you use None?

@mrwizard82d1
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mrwizard82d1 commented Feb 9, 2022 •
edited
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Mea culpa.

Based on the comment, I went back to my original code and successfully passed None for an argument of type Nullable<T>. Additionally, I opened up LinqPad and verified that C# does not allow an expression like var foo = Nullable<Int32>)(null).

I am so sorry for wasting everyone's time.

@mrwizard82d1
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Closing issue.

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@lostmsu @mrwizard82d1