René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Still cannot create Nullable\u003cT\u003e(None)","articleBody":"### Environment\r\n\r\n-   Pythonnet version: 2.5.2\r\n-   Python version: 3.8.7\r\n-   Operating System: Windows 10\r\n-   .NET Runtime: \r\n Runtime Environment:\r\n OS Name:     Windows\r\n OS Version:  10.0.19044\r\n OS Platform: Windows\r\n RID:         win10-x64\r\n Base Path:   C:\\Program Files\\dotnet\\sdk\\6.0.101\\\r\n\r\n### Details\r\n\r\n-   Describe what you were trying to get done.\r\n\r\n   I was trying to invoke a C# function with an argument of type Nullable\u003cT\u003e. Python.NET reported that it could find no function matching the arguments. Eventually, I tried to test the fix for issue #460.\r\n\r\n-   What commands did you run to trigger this issue? If you can provide a\r\n    [Minimal, Complete, and Verifiable example](http://stackoverflow.com/help/mcve)\r\n    this will help us understand the issue.\r\n\r\n```ipython\r\nPython 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)]\r\nType 'copyright', 'credits' or 'license' for more information\r\nIPython 7.28.0 -- An enhanced Interactive Python. Type '?' for help.\r\n\r\n[ins] In [1]: import clr\r\n\r\n[ins] In [2]: from System import (UInt32, Nullable)\r\n\r\n[ins] In [3]: Nullable[UInt32](3)\r\nOut[3]: \u003cSystem.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] object at 0x0000020A6AF106D0\u003e\r\n\r\n[ins] In [4]: Nullable[UInt32](None)\r\n---------------------------------------------------------------------------\r\nTypeError                                 Traceback (most recent call last)\r\n\u003cipython-input-4-b1659b301f87\u003e in \u003cmodule\u003e\r\n----\u003e 1 Nullable[UInt32](None)\r\n\r\nTypeError: No constructor matches given arguments: (\u003cclass 'NoneType'\u003e)\r\n```\r\n\r\n-   If there was a crash, please include the traceback here.\r\n\r\nI also tried testing against pythonnet 3.0.0.a2. I see the following stack trace.\r\n\r\n```ipython                                                                                                  \r\nPython 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)]                                                             \r\nType 'copyright', 'credits' or 'license' for more information                                                                                     \r\nIPython 8.0.1 -- An enhanced Interactive Python. Type '?' for help.                                                                               \r\n                                                                                                                                                  \r\n[ins] In [1]: import clr                                                                                                                          \r\n                                                                                                                                                  \r\n[ins] In [2]: from System import DateTime, Double, Guid, Nullable, String, UInt32                                                                 \r\n                                                                                                                                                  \r\n[ins] In [3]: Nullable[Double](None)                                                                                                              \r\nPython.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                                             \r\n                                                                                                                                                  \r\n                                                                                                                                                  \r\nThe above exception was the direct cause of the following exception:                                                                              \r\n                                                                                                                                                  \r\nSystem.ArgumentException: 'NoneType' value cannot be converted to System.Double in method Void .ctor(Double) ---\u003e Python.Runtime.PythonException: \r\n'NoneType' value cannot be converted to System.Double                                                                                             \r\n                                                                                                                                                  \r\n   --- End of inner exception stack trace ---                                                                                                     \r\n                                                                                                                                                  \r\nThe above exception was the direct cause of the following exception:                                                                              \r\n                                                                                                                                                  \r\nSystem.AggregateException: One or more errors occurred. ---\u003e System.ArgumentException: 'NoneType' value cannot be converted to System.Double in me\r\nthod Void .ctor(Double) ---\u003e Python.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                \r\n                                                                                                                                                  \r\n                                                                                                                                                  \r\n   --- End of inner exception stack trace ---                                                                                                     \r\n   --- End of inner exception stack trace ---                                                                                                     \r\n---\u003e (Inner Exception #0) System.ArgumentException: 'NoneType' value cannot be converted to System.Double in method Void .ctor(Double) ---\u003e Python\r\n.Runtime.PythonException: 'NoneType' value cannot be converted to System.Double                                                                   \r\n                                                                                                                                                  \r\n   --- End of inner exception stack trace ---\u003c---                                                                                                 \r\n                                                                                                                                                  \r\n                                                                                                                                                  \r\nThe above exception was the direct cause of the following exception:                                                                              \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 3251, in run_code                                                                                                                              \r\n                                                                                                                                                  \r\n    exec(code_obj, self.user_global_ns, self.user_ns)                                                                                             \r\n  File \"\u003cipython-input-3-3b78c20f70fb\u003e\", line 1, in \u003cmodule\u003e                                                                                      \r\n    Nullable[Double](None)                                                                                                                        \r\nTypeError: No constructor matches given arguments: (\u003cclass 'NoneType'\u003e)                                                                           \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1934, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = value._render_traceback_()                                                                                                              \r\nAttributeError: 'TypeError' object has no attribute '_render_traceback_'                                                                          \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 3191, in run_ast_nodes                                                                                                                         \r\n                                                                                                                                                  \r\n    if await self.run_code(code, result, async_=asy):                                                                                             \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 3268, in run_code                                                                                                                              \r\n                                                                                                                                                  \r\n    self.showtraceback(running_compiled_code=True)                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1936, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 1105, \r\nin structured_traceback                                                                                                                           \r\n                                                                                                                                                  \r\n    return FormattedTB.structured_traceback(                                                                                                      \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 999, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    return VerboseTB.structured_traceback(                                                                                                        \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 871, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                \r\n                                                                                                                                                  \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 775, i\r\nn format_exception_as_a_whole                                                                                                                     \r\n                                                                                                                                                  \r\n    assert etb is not None                                                                                                                        \r\nAssertionError                                                                                                                                    \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1934, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = value._render_traceback_()                                                                                                              \r\nAttributeError: 'AssertionError' object has no attribute '_render_traceback_'                                                                     \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 2814, in _run_cell                                                                                                                             \r\n                                                                                                                                                  \r\n    return runner(coro)                                                                                                                           \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\async_helpers.py\", line \r\n129, in _pseudo_sync_runner                                                                                                                       \r\n                                                                                                                                                  \r\n    coro.send(None)                                                                                                                               \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 3012, in run_cell_async                                                                                                                        \r\n                                                                                                                                                  \r\n    has_raised = await self.run_ast_nodes(code_ast.body, cell_name,                                                                               \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 3210, in run_ast_nodes                                                                                                                         \r\n                                                                                                                                                  \r\n    self.showtraceback()                                                                                                                          \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1936, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 1105, \r\nin structured_traceback                                                                                                                           \r\n                                                                                                                                                  \r\n    return FormattedTB.structured_traceback(                                                                                                      \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 999, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    return VerboseTB.structured_traceback(                                                                                                        \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 871, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                \r\n                                                                                                                                                  \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 775, i\r\nn format_exception_as_a_whole                                                                                                                     \r\n                                                                                                                                                  \r\n    assert etb is not None                                                                                                                        \r\nAssertionError                                                                                                                                    \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1934, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = value._render_traceback_()                                                                                                              \r\nAttributeError: 'AssertionError' object has no attribute '_render_traceback_'                                                                     \r\n                                                                                                                                                  \r\nDuring handling of the above exception, another exception occurred:                                                                               \r\n                                                                                                                                                  \r\nTraceback (most recent call last):                                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\Programs\\Python\\Python38\\lib\\runpy.py\", line 194, in _run_module_as_main                               \r\n                                                                                                                                                  \r\n    return _run_code(code, main_globals, None,                                                                                                    \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\Programs\\Python\\Python38\\lib\\runpy.py\", line 87, in _run_code                                          \r\n                                                                                                                                                  \r\n    exec(code, run_globals)                                                                                                                       \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\Scripts\\ipython.exe\\__main__.py\", line 7, in \u003cmodule\u003e  \r\n                                                                                                                                                  \r\n    sys.exit(start_ipython())                                                                                                                     \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\__init__.py\", line 123, in st\r\nart_ipython                                                                                                                                       \r\n    return launch_new_instance(argv=argv, **kwargs)                                                                                               \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\traitlets\\config\\application.py\", lin\r\ne 846, in launch_instance                                                                                                                         \r\n                                                                                                                                                  \r\n    app.start()                                                                                                                                   \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\terminal\\ipapp.py\", line 316,\r\n in start                                                                                                                                         \r\n    self.shell.mainloop()                                                                                                                         \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\terminal\\interactiveshell.py\"\r\n, line 611, in mainloop                                                                                                                           \r\n                                                                                                                                                  \r\n    self.interact()                                                                                                                               \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\terminal\\interactiveshell.py\"\r\n, line 604, in interact                                                                                                                           \r\n                                                                                                                                                  \r\n    self.run_cell(code, store_history=True)                                                                                                       \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 2768, in run_cell                                                                                                                              \r\n                                                                                                                                                  \r\n    result = self._run_cell(                                                                                                                      \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 2819, in _run_cell                                                                                                                             \r\n                                                                                                                                                  \r\n    self.showtraceback(running_compiled_code=True)                                                                                                \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\interactiveshell.py\", li\r\nne 1936, in showtraceback                                                                                                                         \r\n                                                                                                                                                  \r\n    stb = self.InteractiveTB.structured_traceback(etype,                                                                                          \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 1105, \r\nin structured_traceback                                                                                                                           \r\n                                                                                                                                                  \r\n    return FormattedTB.structured_traceback(                                                                                                      \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 999, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    return VerboseTB.structured_traceback(                                                                                                        \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 871, i\r\nn structured_traceback                                                                                                                            \r\n                                                                                                                                                  \r\n    formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,                                                \r\n                                                                                                                                                  \r\n  File \"C:\\Users\\larry.jones\\AppData\\Local\\pypoetry\\Cache\\virtualenvs\\libpy-QVeQv1xn-py3.8\\lib\\site-packages\\IPython\\core\\ultratb.py\", line 775, i\r\nn format_exception_as_a_whole                                                                                                                     \r\n                                                                                                                                                  \r\n    assert etb is not None                                                                                                                        \r\nAssertionError                                                                                                                                    \r\n                                                                                                                                                  \r\nIf you suspect this is an IPython 8.0.1 bug, please report it at:                                                                                 \r\n    https://github.com/ipython/ipython/issues                                                                                                     \r\nor send an email to the mailing list at ipython-dev@python.org                                                                                    \r\n                                                                                                                                                  \r\nYou can print a more detailed traceback right now with \"%tb\", or use \"%debug\"                                                                     \r\nto interactively debug it.                                                                                                                        \r\n                                                                                                                                                  \r\nExtra-detailed tracebacks for bug-reporting purposes can be enabled via:                                                                          \r\n    %config Application.verbose_crash=True                                                                                                        \r\n                                                                                                                                                  \r\n\r\n```","author":{"url":"https://github.com/mrwizard82d1","@type":"Person","name":"mrwizard82d1"},"datePublished":"2022-02-09T01:52:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/1693/pythonnet/issues/1693"}