Auto-completion of filename in :write with append flag does not work

[notarock]

Issue type

• Bug report

Environment

Emacs version: GNU Emacs 27.1 Operating System: NixOS 20.09 Evil version: Evil version 1.14.0 Evil installation type: Not sure, I'm using Doom-Emacs Graphical/Terminal: Graphical Tested in a make emacs session (see CONTRIBUTING.md): No

Reproduction steps

• Open a file and type something with evil-mode activated
• Select a part of the file using visual mode
• User the ex command write to try to append to a file (e.g. :w >>directory/path/to/file)
• While writing the file name, press tab to try and use the auto-completion feature
• Auto-completion does not works for the file name (e.g. :w >>direc<press tab> should autocomplete directory)

Expected behavior

I have included a gif of the behavior in vim with no plugins and minimal vimrc:

When I press <tab> while writing the file name, it gets completed.

Actual behavior

I have included a gif of the behavior in evil-mode:

As you can see, when using :w path/to/file, there are candidates for auto-completed when I press tabs. But if I add the >> characters before the filename, the completion no-longer works.

Further notes

I can probably fix this if someone can point me in the right direction :smile: