Add replacing unknown remote function to code actions

[sheldak]

I've prepared that PR to propose extending code actions by replacing unknown remote functions (I did a similar thing in that PR for ElixirLS). For example, the following code:

defmodule Example do
  def foo do
    var = Enum.counts([2, 3])
  end
end

contains an unknown function - counts/1. After this change, we would get 2 possible quick fixes:

Rename to concat
Rename to count

that rewrite our code to:

defmodule Example do
  def foo do
    var = Enum.concat([2, 3])
  end
end

or

defmodule Example do
  def foo do
    var = Enum.count([2, 3])
  end
end

respectively.

In our example, code actions were generated using String.jaro_distance/2 with a threshold of 0.77 to create at most 5 suggestions (similar to did you mean functionality).

[zachallaun]

Thanks for the contribution! I'll look more carefully at this soon but a couple of early points:

1. CI is failing because of a Credo warning -- you can just run mix credo to find/fix.
2. I'd prefer not to generate suggestions by parsing the Elixir error. This seems brittle and prone to breakage if Elixir ever changes how these suggestions are presented. Instead, we should generate the suggestions ourselves using the same mechanism Elixir uses: String.jaro_distance/2. You can get a list of functions/macros from a module with module.__info__/1, and it's easy enough to compare from there.
3. We'd like to move away from using ElixirSense. Look for Lexical.Ast.expand_alises as a replacement for what I think you're currently using it for.

[scohen]

Also, thank you for writing so many tests!

[scohen]

Also, looking at all the work you had to do to add another action makes me think we can improve the process by coming up with a simpler API for code actions, possibly pushing the bulk of their logic into remote_control, so that we only need to call a single function in remote_control to get all the relevant code actions.

[sheldak]

Thanks for a quick response!

2. I'd prefer not to generate suggestions by parsing the Elixir error. This seems brittle and prone to breakage if Elixir ever changes how these suggestions are presented. Instead, we should generate the suggestions ourselves using the same mechanism Elixir uses: String.jaro_distance/2. You can get a list of functions/macros from a module with module.__info__/1, and it's easy enough to compare from there.

That makes sense. However, I have an issue with module.__info__/1 - I cannot use it since the module is not available from Lexical (we only have the module as a document). I did something similar previously here but it required ElixirSense.

3. We'd like to move away from using ElixirSense. Look for Lexical.Ast.expand_alises as a replacement for what I think you're currently using it for.

That should work

[scohen]

That makes sense. However, I have an issue with module.info/1 - I cannot use it since the module is not available from Lexical

I think you need to do this in the project node (the remote_control app). Then you should have access to the module.

[scohen]

@sheldak Check out #453

[sheldak]

@sheldak Check out #453

Thanks, I will rebase to that. I will be able to come back to this PR next week.

[scohen]

@sheldak The PR has been merged, I think this PR is will now be much simpler to implement and test.

[sheldak]

@zachallaun @scohen All changes made!

[scohen]

@sheldak what did you think of the changes?

[scohen]

Looks pretty good. The lion's share of the file changes here are fixtures for testing in the server app.

I have some minor comments, but the approach looks solid to me.

[sheldak]

@sheldak what did you think of the changes?

It was a big improvement. They made everything more concise and I particularly liked not passing all these arguments through several functions to do only code modification in the remote control.

[scohen]

Looking at your Pr, I concur. I just wanted to make sure you felt the same.

[scohen]

@sheldak looks like you're going to need to rebase.

[scohen]

Never mind, i'll do this for you.