Macvim: Updating to snapshot 160 breaks Python support

[romainl]

Describe the bug
The Python interface no longer works after updating MacVim from snapshot 159 to snapshot 160.

To Reproduce
Detailed steps to reproduce the behavior:

1. Put the lines below in /tmp/pythontest.vim to tell Vim where to find Python 3.7:

    " this is from MacPorts, use a path that works for you
    let &pythonthreehome = '/opt/local/Library/Frameworks/Python.framework/Versions/3.7'
    let &pythonthreedll = '/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/libpython3.7.dylib'

1. Start the TUI with:

   $ mvim -vNu /tmp/pythontest.vim
   

   or the GUI with:

   $ mvim -gNu /tmp/pythontest.vim
   

2. Do :echo has('python3').

3. Get a 0.

4. Do :py3 print(1).

5. Get the following errors:

   E370: Could not load library /opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/libpython3.7.dylib
   E263: Sorry, this command is disabled, the Python library could not be loaded.
   

Expected behavior
Both commands should echo 1, without throwing errors.

Environment:

• Vim version: 8.1.2224 (160)
• OS: macOS 10.14.6
• Terminal: Terminal.app and the GUI

First reported:
https://www.reddit.com/r/vim/comments/dotqki/macvim_black_and_python_version_problem/

[eirnym]

@romainl Thank you for an issue,

It's a known problem, #978

[RStankov]

Have the same issues. Any workarounds?

[romainl]

@RStankov I worked around the issue by rolling back to snapshot 159. I'll wait and see for snapshot 161.

[ychin]

This will be fixed in snapshot 161 which will come out in a day or so. The cause of this was that snapshot-160 turned on hardened runtime for app notarization requirements but it messed with Python and other scripting languages.

For now, Apple allows using much more lenient restrictions so I'm going to work around the issue and get the app notarized, but they are going to tighten up what they allow to be notarized soon (Janurary 2020) so I'll need to find a real solution for this problem.

[ychin]

Fixed in 161: https://github.com/macvim-dev/macvim/releases/latest