IronPython error under .Net Core: "failed to parse CPython sys:version"-CodePudding

I have a .Net 4.x WPF desktop solution that uses IronPython to run numerous scripts in the form of .py files. I've just finished migrating the solution to .Net 6, but I see this error when the software tries to run a particular script:

IronPython.Runtime.Exceptions.ValueErrorException: 'failed to parse CPython sys.version: '2.7.12 (2.7.12.1000)\n[.NETCoreApp,Version=v3.1 on .NET 6.0.6 (64-bit)]''

The .py file that fails simply displays the Python version:

import platform

...

print 'Using Python {0}'.format(platform.python_version())

How can I resolve this problem? Modifying the .py file is out of the question (at this stage), as we have a large customer base, all with the same script installed on their PCs.

CodePudding user response：

I've found one solution, which is to execute the following script after creating the ScriptEngine object, to replace the version with a hardcoded string:

_scriptEngine.Execute(@"
import sys
version_bak = sys.version
sys.version = '2.7.12 (IronPython 2.7.12 (2.7.12.1000) on .NET 
6.0.0.0 (64-bit))'
import platform
platform.python_implementation()
platform._sys_version_cache[version_bak] = 
platform._sys_version_cache[sys.version]
sys.version = version_bak
");

This works, and I can further refine it to use the correct IronPython and .Net version no.s rather than hardcode those. Just wondering if there is a better solution out there though, such as manipulating the version number via IronPython classes rather than have to run this script each time?

CodePudding user response：

I've discovered an easier way to change the version string is as follows that doesn't involve running a script as per my other answer:

_scriptEngine.Runtime.SetHostVariables(
    "", 
    "", 
    "2.7.12 (IronPython 2.7.12 (2.7.12.1000) on .NET 6.0.0.0 (64-bit))");

The hardcoded string can be refined by dropping in the current IronPython and .Net versions like so:

var ironPythonVer = _engine.LanguageVersion;
var netVer = Environment.Version;
_scriptEngine.Runtime.SetHostVariables(
    "", 
    "", 
    "{ironPythonVer} (IronPython {ironPythonVer} ({ironPythonVer}.0) on .NET {netVer} (64-bit))");