fix: force Git fetch during updates

[antoineco]

Fixes #1100

I believe --force is a sensible default in the context of packer updates. In most cases, users don't care about things such as force-pushed tags, and simply want packer to pull whatever Git ref was indicated in their config.

[overhacked]

Due to the condition:

packer.nvim/lua/packer/plugin_types/git.lua

Lines 221 to 223 in 64ae65f

	if plugin.commit or plugin.tag then
	update_cmd = fetch_cmd
	end

The fetch command also needs to be --force, like:

      fetch = 'fetch --depth 999999 --progress --force',

[antoineco]

@overhacked in what context have you been running into issues with the fetch command?

Edit: I just saw your comment on the original issue. Good point.

[wbthomason]

@antoineco @overhacked Thanks, and sorry for the delay here. If we're to merge this, we should add @overhacked's suggested change.

Also, are there cases where --force might not do what we want? I don't know of any (as you say, users typically just want "get the latest" or "get the thing I specified", and afaik --force will do the right thing in these cases), but I don't entirely trust my knowledge of git to be exhaustive enough here.

[antoineco]

@wbthomason absolutely 👍 Done in e1979615..3a4fff64

[overhacked]

@wbthomason @antoineco Not sure why this got closed? #1100 is still open; I posted my enthusiastic agreement (#1100 (comment)) with this PR's approach there. I'm closing #1171; it would over-complicate the matter.

[antoineco]

@overhacked it was closed because you disagreed with the approach in the original issue and opened #1171 instead.

I have since deleted my fork and no longer use packer, but by any mean feel free to re-submit.

[overhacked]

Understood. I was wrong about the approach being harmful. I'll resubmit.