Support Python 3.8

[janEntikan]

Importing cefpython with python 3.8 raised:
Exception: Python version not supported: 3.8.0 (default, Oct 23 2019, 18:51:26)

Arch Linux's package manager installs/updates to python 3.8. Downgrading is non-trivial.

[gregorias]

If you use an Arch Linux distro, I can also recommend installing and using python36. I find it a more convenient stop-gap measure than downgrading.

[janEntikan]

I ended up using pyenv. Thanks for the tip, though!

[coderextreme]

A new release for python 3.8.1 would be welcome, for those of us who have already upgraded. Thanks for your hard work!

[cztomczak]

Take a look at commit 1c61629 which added Python 3.7 support. It changed only a few files. To add Python 3.8 support make similar changes to these files. Then build it by following the build instructions. It might be required to update Cython module version (see tools/requirements.txt and build instructions). Pull requests are welcome.

Updated.

[alexdelorenzo]

Don't have the resources to spare to patch, build and test this project, but I'd love to use it with Python 3.8. Thanks for your work @cztomczak

[simonsan]

Keep in mind:

Python 3.8 changes the behaviour of resolving DLLs on Windows.

DLL dependencies for extension modules and DLLs loaded with ctypes on Windows are now resolved more securely. Only the system paths, the directory containing the DLL or PYD file, and directories added with add_dll_directory() are searched for load-time dependencies. Specifically, PATH and the current working directory are no longer used, and modifications to these will no longer have any effect on normal DLL resolution. If your application relies on these mechanisms, you should check for add_dll_directory() and if it exists, use it to add your DLLs directory while loading your library. Note that Windows 7 users will need to ensure that Windows Update KB2533623 has been installed (this is also verified by the installer). (Contributed by Steve Dower in bpo-36085.)

Src.: https://docs.python.org/3/whatsnew/3.8.html#bpo-36085-whatsnew

[rlaphoenix]

Just to mention, it works fine on Python 3.8 with literally no changes to the actual code other than how it's imported:

Change:

elif sys.version_info[:2] == (3, 7):

to:

elif sys.version_info[:2] in [(3, 7), (3, 8)]:

Works perfectly fine, been using it like this for months without encountering a single problem.

[cztomczak]

This is not recommended.

[cztomczak]

cefpython modules are compiled for specific Python versions. What you're doing is a hack and many bad things could happen to your app. This is unsupported and dangerous. You've been warned.

[rlaphoenix]

cefpython modules are compiled for specific Python versions. What you're doing is a hack and many bad things could happen to your app. This is unsupported and dangerous. You've been warned.

I'm aware, I tried to compile for python 3.8 on my own arch linux machine, but I encountered issues with pango trying to load hb.h (harfbuzz.h, which with some manual overrides fixed), and then issues with GTK in some way, eventually it just failed to compile. I was following the Build instructions in Knowledge Base file.

I know its a total hack and generally unsupported, but I've literally been using it in all kinds of setups for months without a single problem, and I'm not exaggerating.

[avollmerhaus]

Ubuntu 20.04 comes with python3.8, so there's that :)

[matthewhampton]

Hi @cztomczak. I'm trying to get this done based on your earlier advice. (see https://github.com/j5int/cefpython/tree/cefpython66-py38 for WIP)

I'm starting on windows, and am getting one unittest failure and I was wondering if you could give me some pointers?

(It seems to be working OK)

This is the failure:

======================================================================
FAIL: test_main (main_test.MainTest_IsolatedTest)
Main entry point. All the code must run inside one
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\mhampton\work\git\cefpython\unittests\main_test.py", line 304, in test_main
    check_auto_asserts(self, [] + client_handlers
  File "C:\Users\mhampton\work\git\cefpython\unittests\_common.py", line 88, in check_auto_asserts
    test_case.assertTrue(value, "Check assert: " +
AssertionError: False is not true : Check assert: GlobalHandler.HasDevTools_True

----------------------------------------------------------------------

And the root cause seems to be this:

29. browser.CloseBrowser() ok
Traceback (most recent call last):
  File "task.pyx", line 85, in cefpython_py38.PyTaskRunnable
  File "C:\Users\mhampton\work\git\cefpython\unittests\_common.py", line 134, in close_devtools
    global_handler.HasDevTools_True = main_browser.HasDevTools()
AttributeError: 'NoneType' object has no attribute 'HasDevTools'

Which leads to this func - so evidentally cef.GetBrowserByIdentifier(MAIN_BROWSER_ID) is returning None

def close_devtools(global_handler):
    main_browser = cef.GetBrowserByIdentifier(MAIN_BROWSER_ID)
    global_handler.HasDevTools_True = main_browser.HasDevTools()
    main_browser.CloseDevTools()
    subtest_message("DevTools popup ok")

Any help would be much appreciated.