Inaccurate vim emulation in marker placement when using insert-mode remappings

[ekiefl]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: Code 1.81.1 (Universal) (6c3e3db, 2023-08-09T22:20:33.924Z)
• OS Version: Darwin arm64 22.5.0

List of extensions:

Extension	Author (truncated)	Version
python	ms-	2023.14.0
vscode-pylance	ms-	2023.8.20
material-icon-theme	PKi	4.29.0
vscode-sort-json	ric	1.20.0
find-it-faster	Tom	0.0.25
vim	vsc	1.25.2

Steps to reproduce / description

I like to make a marker whenever I exit insert mode. Here's a toy example where I replace a word via this approach:

Starting with this file:

this_is_a_variable = old_name
new_name

Using the vim command sequence:

gg$ciw<esc>mfjyiw`fp

Yields the following modification to said file:

this_is_a_variable = new_name
new_name

This behavior is consistent between vim and VSCode.

In vim, you can automate making the marker f with an insert-mode remapping:

" when exiting insert mode, the marker f is made
inoremap <esc> <esc>mf

This shortens the command sequence and preserves the behavior when in vim:

before: gg$ciw<esc>mfjyiw`fp
after:  gg$ciw<esc>jyiw`fp

But making the equivalent remapping in the VSCode settings.json reveals a bug in VSCode's vim emulation. Applying the new command sequence, instead of this:

this_is_a_variable = new_name
new_name

you get this:

this_is_a_varianew_nameble = 
new_name

The marker is displaced left of it's correct location, and by an amount equal to the difference in line length before versus after the change (c) operation.

Here is the settings.json used:

{
    "vim.insertModeKeyBindings": [
        {"before": ["<esc>"], "after": ["<esc>", "m", "f"]}, // FIXME
    ]
}

It would be nice if this were fixed, or if a hack existed to correct the behavior.

[ekiefl]

Wrong repo, sorry.