Python 3: Package structure and relative imports

[dgelessus]

I've been looking at Stash's package structure a bit (for the universal branch). I noticed that many modules use implicit relative imports (e. g. stash.py imports system.shcommon, which actually imports stash.system.shcommon) which do not work under Python 3. This is not a big issue, most of these can be replaced with real relative imports (e. g. from .system import shcommon).

The second issue (not directly related to the first one) is that the repo root is the stash package folder, i. e. site-package/stash is the repo root. This means that you have to clone the repo into site-packages/stash, or some imports (for example in launch_stash.py will fail). So it's not possible to have two versions of Stash installed without changing the package name and adjusting imports.

A solution to this would be to move all Stash module files (like stash.py and system) into a stash subfolder, while leaving non-module files in the repo root (like launch_stash.py). This would make installing multiple versions or switching between branches much easier. The launch_stash.py would be in the same folder as the stash package, so when it imports stash it automatically uses the version next to it instead of the one from site-packages.

For normal users nothing would change - if there is no stash package in the same folder as launch_stash.py, it looks through the other module locations, including site-packages. getstash.py would only need some minor modifications to copy the stash folder into site-packages and not the entire repo.

[ywangd]

Yes the relative imports need to be fixed. Thanks.

However, having multiple stash installations is actually something I try to avoid. I agree it is useful for development purpose. But for most users, this possibility is more likely to cause confusions, e.g. one may wonder why selfupdate does not work as it is probably updating another version which is not the currently running one.

[dgelessus]

Yes, that's understandable, users shouldn't install multiple stash instances by accident. However I don't think this change would affect stash installations in site-packages - as long as we change getstash.py to understand the new structure, selfupdate would work the same as before for normal users.

The difference is that with the old structure, when you clone the repo by hand into a different folder, the launch_stash.py in the repo would still use the stash installation in site-packages, and not the one in the cloned repo. With the new structure, launch_stash.py would prefer importing stash from the current directory, and fall back to site-packages if there is no valid stash package next to the launch_stash.py.