fix commits are based on HEAD of target branch, not PR

[scarf005]

Summary

- A (merge base) - B (remote HEAD)
   \
	C (PR HEAD) - C' (auto-fixed commit)

when autofix.ci creates commit C' from C, it seems to apply changes on top of B, not C.

Example

let's assume repo for above graph

• only tracks file.txt
• uses formatter that converts lines to CapitalCase, so foo -> Foo

on commit A:

1. Hello
2. World

on commit B:

- 1. Hello
2. World

on commit C:

1. Hello
2. World
+ 3. person

on commit C', the auto-fixed one also applies changes from commit B:

- 1. Hello
2. World
- 3. person
+ 3. Person

I find this a bit odd, because i was expecting the formatting to be localized to C, like:

1. Hello
2. World
- 3. person
+ 3. Person

Workflow Run With the issue

before formatting

In locations_commercial.json, line 343 is inserted.

During formatting

diff --git a/data/json/itemgroups/Locations_MapExtras/locations_commercial.json b/data/json/itemgroups/Locations_MapExtras/locations_commercial.json
index faa4415..17dcf92 100644
--- a/data/json/itemgroups/Locations_MapExtras/locations_commercial.json
+++ b/data/json/itemgroups/Locations_MapExtras/locations_commercial.json
@@ -337,7 +337,7 @@
       [ "bandolier_shotgun", 8 ],
       [ "torso_bandolier_shotgun", 3 ],
       [ "holster", 8 ],
-	  [ "shoulder_holster", 4 ],
+      [ "shoulder_holster", 4 ],
       [ "bootstrap", 2 ],
       [ "wristholster", 1 ],
       [ "bholster", 5 ],

In the log, we can find out that for locations_commercial.json, only line 343 is formatted.

After formatting

However, in the commit autofix.ci has made, line 14 to 16 is also removed.

corresponding commit URLs since the PR branch is now deleted

• merge-base fix(content): Update ergonomic grips to work for shotguns (#3974)
• repo-head-back-then fix(content): Remove Rivtech guns from spawning in various commercial locations (#3975)
• feat(content): shoulder holsters
• autofix-oddity style(autofix.ci): automated formatting

This is unexpected because the PR's merge base was older than its removal.

Additional Context

cataclysmbnteam/Cataclysm-BN#3981 (comment)

[mhils]

Ughs, thanks for catching this! This definitely is a bug in the action right now. I guess we need to do something like this to fix it:

1. Create commit with all changes.
2. Check out PR head.
3. Cherry-pick the commit from step 1.
4. Generate autofix.json as we already do.