Return correct has_satellite

[adlerd]

Progress bars are being disabled even when satellite is not present. Returning false from satellite.lua in this case restores the progress bars.

[Julian]

@adlerd sincere apoogies, somehow I totally missed this PR. I definitely do see something isn't working in this case but I honestly don't really understand why? Maybe you looked?

Specifically, we check against nil, and we seem to return nil... does Lua do something magical if you return nil from a module, or yeah I don't see why it's broken at the minute, which I'd like to understand before merging. Let me know if you've already had a look, and sorry again for only just noticing.

[adlerd]

After a recent update I lost progress bars. I can reproduce locally that when I apply this patch, I get progress bars back; and when I undo this patch, I lose them again.

I can't explain it either in terms of the Lua book and I don't have any "real-world" Lua experience. However, without this patch, the following code does not call notify(), when run via :lua ex command. (With this patch, it does call notify() as expected.)

local has_satellite = require 'lean.satellite'
if not has_satellite then
  vim.notify("not has_satellite")
end

This behavior differs from my local installation of luajit when it requires a file containing just return, so there's either a behavior change due to lua version or something funny about neovim's require.

[adlerd]

Ah. vim.print(tostring(require 'lean.satellite')) prints true, and :help require states,

If the loader
returns no value and has not assigned any value to
package.loaded[modname], then require assigns true to this
entry.

In theory, since Lua has multiple-returns, return might be returning no values, rather than nil; and in theory, the "loader" (which :help is a bit vague on) might be correctly passing through multiple values. Actually it doesn't seem to matter, since return nil also gives no progress bars and stores true in the table. neovim's require appears to "helpfully" reinterpret a nil return from modules as generic success, whereupon it stores true.

[Julian]

Fun... OK. Thanks for tracking this down and for the PR!