Fix coercion broken by a user-defined Func function

[lacygoill]

MWE:

Start Vim like this:

$ vim -Nu NORC +'set rtp^=/path/to/vim-abolish'

Execute on the command-line:

:fu! Func() ^@ endfu

^@ is a NUL inserted by pressing C-v C-j.

Insert a word in the buffer:

iword

Escape to get back to normal mode, and press cru to make it uppercase.
It raises the following error:

Error detected while processing function <SNR>1_coerce[11]..<SNR>1_send:
line    2:
E705: Variable name conflicts with existing function: Func

I think the issue comes from an assignment in the s:send() function.
Usually, the l: scope is useless unless you use one of these 5 variables:

count
errmsg
shell_error
this_session
version

Because they're the only ones with the VV_COMPAT flag.
But l: is also useful when you create a funcref inside a function, as its name can conflict with an outer public function.

In s:send(), I think that the variable Func refers to a funcref, and so should be scoped with l: to avoid a conflict with a user-defined function named Func.

This is an issue which I encounters often as I'm frequently creating a function Func when prototyping a new function and I don't want to think about a name yet.

I'm not familiar with the code, so I don't know whether the PR breaks something else, but in my limited usage of the plugin, it didn't seem to cause an issue.

Feel free to close the PR if there's another way of fixing the issue.
Thank you very much for your plugin.

[tpope]

I bet you can fix the issue by changing this line and this line alone. Can you confirm/refute?

[lacygoill]

I'm sorry, I don't know much about git or github, so when you say "this line", I'm not sure what line I should change.
Just above your comment I can see these 2 lines in red:

if type(Func) == type(function('tr'))
  return call(Func,a:000,s)

So, I assume you want me to only scope the first 4 occurrences of Func like this:

if type(a:func) == type('') || type(a:func) == type(0)
  let l:Func = get(a:self,a:func,'')
else
  let l:Func = a:func
endif
if type(l:Func) == type(function('tr'))
  return call(l:Func,a:000,s)

If that's what you meant, then yes, I've just made a test and it fixes the issue.

Do you want me to push another commit and only change these 4 occurrences, and leave the 10 other ones alone?

[tpope]

Just the return call(Func,a:000,s) line is what I was thinking. If that works then yes, I'd favor the single line diff.

[lacygoill]

Ok, I've just made a test, the only change being this line:

return call(Func,a:000,s)

Replaced by this line:

return call(l:Func,a:000,s)

But unfortunately, the issue still persists.

[tpope]

Oh, it must be the 2 assignment lines.

[lacygoill]

I agree, I think the error comes from the assignments, that's why I scoped them with l: in the commit.
And since I did that for the assignments, I felt it was necessary to go on and do the same for all the other occurrences, otherwise I thought that Func would refer to the user-defined function, instead of the local funcref.

If I only scope the assignments, when I press cru, something weird happens (the word is deleted, or the cursor moves and a character is deleted somewhere else); it depends on what the current line contains...

However, as I said in the previous post, if I scope only the first four occurrences, then this issue is fixed.
So if you want me to scope only them, and leave the other alone, I'll do it and push another commit.

Although, I'm not sure a similar issue would not happen if s:send() had to process the following elseif statements where Func is unscoped.
FWIW, I always scope a funcref with l: to avoid having headaches trying to understand what Vim will understand. But I admit I have far less experience in VimL than you, so if it's fine by you, it's fine by me.

[tpope]

I favor the minimum possible diff which appears to be the 2 assignment lines. Since you closed this I'll take care of it. Thanks for the recon!