System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034

levihb · 2020-01-24T12:30:50Z

Environment

Pythonnet version: Tried latest from pip, latest from git
Python version: Tried 3.5, 3.7, 3.8
Operating System: Arch Linux

Details

Trying to import clr so that I can import a library.

import clr

When trying to import this, the following error is thrown:

>>> import clr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: System.DllNotFoundException: /usr/lib/../lib/libmono-native.so assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Interop+Sys.GetNonCryptographicallySecureRandomBytes(byte*,int)
  at Interop.GetRandomBytes (System.Byte* buffer, System.Int32 length) [0x00000] in <894a218ab05a4151a4fb84b414f81888>:0 
  at System.Guid.FastNewGuidArray () [0x00020] in <894a218ab05a4151a4fb84b414f81888>:0 
  at System.Reflection.Emit.ModuleBuilder..ctor (System.Reflection.Emit.AssemblyBuilder assb, System.String name, System.String fullyqname, System.Boolean emitSymbolInfo, System.Boolean transient) [0x00035] in <894a218ab05a4151a4fb84b414f81888>:0 
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name, System.String fileName, System.Boolean emitSymbolInfo, System.Boolean transient) [0x0005b] in <894a218ab05a4151a4fb84b414f81888>:0 
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name) [0x00000] in <894a218ab05a4151a4fb84b414f81888>:0 
  at Python.Runtime.CodeGenerator..ctor () [0x0002b] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.DelegateManager..ctor () [0x00061] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv, System.Boolean initSigs) [0x0000a] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv, System.Boolean initSigs) [0x00005] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.InitExt () [0x00000] in <1d25771ef5ab45e58a874c804663e59c>:0 
>>>

I'm not sure what is going on, msbuild and mono work just fine, the referenced libmono-native library exists in the location specified (not sure why it drops back a directory, then goes back into lib though?).

levihb · 2020-01-24T16:06:08Z

After upgrading to Mono 6.11, I get the following, slightly different error:

>>> import clr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: System.TypeInitializationException: The type initializer for 'Sys' threw an exception. ---> System.DllNotFoundException: /lib/../lib/libmono-native.so assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Interop+Sys.LChflagsCanSetHiddenFlag()
  at Interop+Sys..cctor () [0x00000] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
   --- End of inner exception stack trace ---
  at Interop.GetRandomBytes (System.Byte* buffer, System.Int32 length) [0x00000] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
  at System.Guid.FastNewGuidArray () [0x00020] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
  at System.Reflection.Emit.ModuleBuilder..ctor (System.Reflection.Emit.AssemblyBuilder assb, System.String name, System.String fullyqname, System.Boolean emitSymbolInfo, System.Boolean transient) [0x00035] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name, System.String fileName, System.Boolean emitSymbolInfo, System.Boolean transient) [0x0005b] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name) [0x00000] in <c2db598b04474bb8b2ca952ec0b0ce8b>:0 
  at Python.Runtime.CodeGenerator..ctor () [0x0002b] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.DelegateManager..ctor () [0x00061] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv, System.Boolean initSigs) [0x0000a] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv, System.Boolean initSigs) [0x00005] in <1d25771ef5ab45e58a874c804663e59c>:0 
  at Python.Runtime.PythonEngine.InitExt () [0x00000] in <1d25771ef5ab45e58a874c804663e59c>:0

intendednull · 2020-03-09T20:57:20Z

I am experiencing an identical issue. Also on Arch Linux.

(venv) [13:57] zer0:pythonnet (master) $ python -c "import clr"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: System.DllNotFoundException: /usr/lib/../lib/libmono-native.so assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Interop+Sys.GetNonCryptographicallySecureRandomBytes(byte*,int)
  at Interop.GetRandomBytes (System.Byte* buffer, System.Int32 length) [0x00000] in <c4bddbfe864a4b8191bb818d6b204e9d>:0
  at System.Guid.FastNewGuidArray () [0x00020] in <c4bddbfe864a4b8191bb818d6b204e9d>:0
  at System.Reflection.Emit.ModuleBuilder..ctor (System.Reflection.Emit.AssemblyBuilder assb, System.String name, System.String fullyqname, System.Boolean emitSymbolInfo, System.Boolean transient) [0x00035] in <c4bddbfe864a4b8191bb818d6b204e9d>:0
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name, System.String fileName, System.Boolean emitSymbolInfo, System.Boolean transient) [0x0005b] in <c4bddbfe864a4b8191bb818d6b204e9d>:0
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name) [0x00000] in <c4bddbfe864a4b8191bb818d6b204e9d>:0
  at Python.Runtime.CodeGenerator..ctor () [0x0002b] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.DelegateManager..ctor () [0x00061] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv, System.Boolean initSigs) [0x0000a] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv, System.Boolean initSigs) [0x00005] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.InitExt () [0x00000] in <78c98e72d96d408ea33ed377e3ab5fd1>:0

lostmsu · 2020-03-09T21:52:00Z

Judging by stack trace, this must be a Mono issue. You can try reproducing it by opening C# REPL and running System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule("__CodeGenerator_Module").

intendednull · 2020-03-12T20:11:14Z

Compiled mono master branch directly and ~~it seems to be fixed (mono v16.13.0)~~ now a different dll is missing

[13:12] zer0:mono (master) $ python -c "import clr"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: libmonosgen-2.0.so.1: cannot open shared object file: No such file or directory

Turns out it just wasn't in my path. Fixing that gets me a slightly different error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: System.TypeInitializationException: The type initializer for 'Sys' threw an exception. ---> System.DllNotFoundException: /usr/local/lib/../lib/libmono-native.so assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Interop+Sys.LChflagsCanSetHiddenFlag()
  at Interop+Sys..cctor () [0x00000] in <41515cbda246402e80204eed794202d2>:0
   --- End of inner exception stack trace ---
  at Interop.GetRandomBytes (System.Byte* buffer, System.Int32 length) [0x00000] in <41515cbda246402e80204eed794202d2>:0
  at System.Guid.FastNewGuidArray () [0x00020] in <41515cbda246402e80204eed794202d2>:0
  at System.Reflection.Emit.ModuleBuilder..ctor (System.Reflection.Emit.AssemblyBuilder assb, System.String name, System.String fullyqname, System.Boolean emitSymbolInfo, System.Boolean transient) [0x00035] in <41515cbda246402e80204eed794202d2>:0
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name, System.String fileName, System.Boolean emitSymbolInfo, System.Boolean transient) [0x0005b] in <41515cbda246402e80204eed794202d2>:0
  at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name) [0x00000] in <41515cbda246402e80204eed794202d2>:0
  at Python.Runtime.CodeGenerator..ctor () [0x0002b] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.DelegateManager..ctor () [0x00061] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv, System.Boolean initSigs) [0x0000a] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv, System.Boolean initSigs) [0x00005] in <78c98e72d96d408ea33ed377e3ab5fd1>:0
  at Python.Runtime.PythonEngine.InitExt () [0x00000] in <78c98e72d96d408ea33ed377e3ab5fd1>:0

intendednull · 2020-03-13T23:09:39Z

There's a similar issue open over at mono/mono#17079

So far everyone encountering the issue has been using Arch and Python.

lostmsu · 2020-03-15T02:43:16Z

@Zer0897 as a workaround you could try adding the true path to libmonosgen-2.0.so.1 to PATH?

intendednull · 2020-03-15T20:48:12Z

@lostmsu Yeah I was able to get that recognized by adding it to path, but libmono-native.so is still not found. I feel like this path is super fishy /usr/local/lib/../lib/libmono-native.so. If it's not expanding correctly then it may be the culprit.

filmor · 2020-05-10T18:28:01Z

I'm actually observing the same issue on my Gentoo system, looking into it. The path is fine, the actual issue (if you run with MONO_LOG_LEVEL=debug) seems to be that Mono fails to find the symbol mono_add_internal_call_with_flags while running (or loading) libmononative.so. However, that symbol is defined in libmonosgen-2.0.so which is already loaded, so the issue seems to be with Mono's P/Invoke implementation seems to get confused with libraries that require Mono's own symbols.

b0g2 · 2020-05-10T19:05:39Z

I experienced a similar problem in Ubuntu 18.4, not via import clr but by loading the mono embedded runtime from a Python extension library written in C++ (I am not using PythonNet). There were a lot of exceptions similar to the ones mentioned here, including failing to find the symbol mono_add_internal_call_with_flags.

For me, the solution was to pre-load libmono-2.0.so and libstdc++.so (important: this library contains the _ZTIPi symbol)

LD_PRELOAD="libmono-2.0.so libstdc++.so" python3 test/test.py

By doing this, the problem went away. It can also be done from code, via dlopen, prior to import clr.

Masutani · 2021-04-26T12:23:14Z

Same issue on Amazon Linux in SageMaker : https://stackoverflow.com/questions/67212443/pythonnet-on-sagemaker-cannot-import-clr

lostmsu · 2021-04-27T07:46:21Z

@Masutani there's a workaround for 2.4.0 mentioned above. Previews of 3.0.x do not have this issue anymore.

intendednull mentioned this issue Mar 13, 2020

ImportError: System.TypeInitializationException mono/mono#17079

Open

lostmsu mentioned this issue Apr 22, 2020

ImportError undefined symbol _ZTIPi on import clr #939

Closed

filmor mentioned this issue May 10, 2020

Link stdc++ #1139

Merged

4 tasks

filmor closed this as completed in #1139 May 11, 2020

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System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034

System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034

levihb commented Jan 24, 2020 •

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intendednull commented Mar 12, 2020 •

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lostmsu commented Mar 15, 2020

intendednull commented Mar 15, 2020

filmor commented May 10, 2020

b0g2 commented May 10, 2020

Masutani commented Apr 26, 2021

lostmsu commented Apr 27, 2021

System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034

System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034

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levihb commented Jan 24, 2020 • edited Loading

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levihb commented Jan 24, 2020

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lostmsu commented Mar 15, 2020

intendednull commented Mar 15, 2020

filmor commented May 10, 2020

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