Allow included/load'd files to use tilt extensions

[bobjackman]

It's very helpful to be able to organize your tiltfile by separating sections out into smaller files that can be included into the main Tiltfile. However, those sub-files are unable to make use of tilt extensions. There are 2 ways we can fail at this:

Attempt, the first

Main Tiltfile

include('otherfile.tilt')  # this is just more tiltfile, NOT an extension, and NOT defining shared functions

Other Tiltfile

load('ext://someExtension', 'someFunction')
someFunction('doAThing')

This fails with: Error: cannot load ext://git_resource: extensions cannot be loaded from `load`ed Tiltfiles which is confusing, since this file was included, not loaded.

Ok, so let's load the extension first, and then include our sub-file...

Attempt, the second

Main Tiltfile

load('ext://someExtension', 'someFunction')  # load this first, so our included file can make use of it
include('otherfile.tilt')  # this is just more tiltfile, NOT an extension, and NOT defining shared functions

Other Tiltfile

someFunction('doAThing')

This one fails with: Error: /path/to/otherfile.tilt:1:1: undefined: someFunction which suggests the included file doesn't share global context with the main tiltfile.

*If included files aren't capable of using extensions, it creates a major limitation to organizing our scripts in this fashion.

[bobjackman]

@victorwuky is this relatively simple enough that it might land soon, or is it more likely a ways down the line?

[bobjackman]

@victorwuky for what it's worth, while it would definitely be nice for extensions to also load files, it seems to me like that's less important than the ability for non-extension, local includes to be able to make use of existing extensions.

[wu-victor]

Thanks @kogi for the comment. Right now we don't have a clear timeline of when we'd pick up this feature in particular.

[maiamcc]

@kogi to give a little more context, it turns out this feature isn't actually that simple because (among other things) we'd need to do a lot of work around handling working directories and all the inevitable edge cases. So--we'll keep you posted!

[nicks]

@maiamcc can you elaborate a bit more on why this is difficult to solve?

Ya, it seems like this should be much higher priority if it blocks the ability to use the restart_process extension

[nicks]

@maiamcc Your comment on tilt-dev/tilt-extensions#37 makes me think you might be confusing two different issues:

1. load()-ing extensions from other extensions raises questions about how we version extensions, and handle diamond dependencies (extensions should be able to load other extensions #3472)
2. load()-ing extensions from other sub-included files in the "normal" repo doesn't raise any versioning concerns, and is much easier to resolve

[bobjackman]

# 1 would be nice
# 2 is what this issue is asking for

[nicks]

@maiamcc how do you feel about removing the restart_process deprecation warning until this issue is resolved? seems like this issue is a blocker to adoption of restart_process.

[maiamcc]

Ugh yeah I was hoping it wouldn't be that hard to fix this issue, but since it's almost 3, I guess I'll revert the deprecation warning for today's release :-/

[maiamcc]

This should be fixed in the latest release -- let us know if you run into any trouble!

[bobjackman]

Woo! Works like a charm! Thank you all!