Partially revert commit that broke using emrun.py outside the tree

[juj]

Partially revert commit that broke using emrun.py outside the tree. People often deploy emrun.py into their own CIs and infrastructure outside Emscripten.

commit 4fc6505
Author: Sam Clegg sbc@chromium.org
Date: Sun Sep 13 19:05:11 2020 -0700

Use shared wrappers for shutils. NFC. (#12200)

We we not being consistent in our use of safe_copy and
safe_move and try_delete.

[juj]

Also fixed emrun to be python 2 compatible (not sure when it lost that support).

[sbc100]

Sorry I was unaware that we want to be able run emrun outside of the emscripten tree or that we needed to be able to run it under python 2.

We should add some tests for both of these requirements if we want to keep them. In particular, I wonder if we can drop the python2 requirement since it makes testing harder. The out-of-tree requirement seems easy enough to test, but what is the use case exactly?

[juj]

I don't know if it is viable to add python2 testing for this, since we don't depend on it anymore.

The use case is that people download this tool separately out of Emsdk/Emscripten repo, to use it locally to run web servers on their system. They may not have python 3, running into issues.

[sbc100]

I don't know if it is viable to add python2 testing for this, since we don't depend on it anymore.

The use case is that people download this tool separately out of Emsdk/Emscripten repo, to use it locally to run web servers on their system. They may not have python 3, running into issues.

But do we have users that do that? This is the first time I'm hearing about it. I don't mind doing extra work here if folks really use it this way, I just want to check it worth our time.

[sbc100]

lgtm

However, we really should add tests if we want to support:

a) running emrun out-of-tree
b) running emrun run out-of-tree with only python2 available

Are we sure we have users that need both of these?

If so, and we want to continue to support these users, we should really have tests for both these configurations.

@kripken do you know of any such users?

[juj]

The source of these python 2 users come from Unity users who are looking for an ad hoc server to use. Some of those have had just python2 installed (presumably on macOS with no python3 installation).

I am fine keeping python 2 weakly supported for this script. There are really not much active changes going to it, except recent cosmetic refactoring, so I don't expect it to actively break left and right if it is not tested.

[kripken]

I'm not aware of additional users, but @juj's use case sounds valid to me. Testing of python2 there seems reasonable.