Is it possible to recover changes lefthook reverts and were not staged when running lefthook?

[Fydon]

I'm had issues with lefthook duplicating changes when running it on a repository that didn't have any commits. However now that I have commits I've just had an issue where I staged most of the changes but left some unstaged comments about changes that I still needed to apply and work I was progressing with. However after running lefthook (lefthook run pre-commit) it returned the following error and almost all the uncommitted changes were gone (untracked files were fine; 2 files with changes but none staged were fine; all files with some staged changes retained only the staged changes)

│  > git apply -v --whitespace=nowarn --recount --unidiff-zero /workspaces/foo/.git/info/lefthook-unstaged.patch                                    
│    Checking patch module/cluster/README.md...                                                                                                                        
│    error: while searching for:                                                                                                                                       
│    | [aws_security_group.bar1](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group) | resource | 
│    | [aws_security_group.bar2](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group) | resource |
│    error: patch failed: module/cluster/README.md:32                                                                                                                  
│    error: module/cluster/README.md: patch does not apply                                                                                                             
│    Checking patch module/foo/main.tf...                                                                                                              
│    Hunk #1 succeeded at 17 (offset 1 line).                                                                                                                          
│    Hunk #3 succeeded at 203 (offset 1 line).                                                                                                                         
│                                                                                                                                                                      
│  Couldn't restore unstaged files: couldn't apply the patch /workspaces/foo/.git/info/lefthook-unstaged.patch: exit status 1

/workspaces/foo/.git/info/lefthook-unstaged.patch was missing almost all the changes and the 2 stashes named lefthook auto backup only contained the staged changes.

Does lefthook retain a backup of the changes it reverts? Is there a setting to not have it make destructive changes?

I can't think clearly now, having lost quite a bit of work, but the only thing I might have done is stage minor a change after running lefthook. lefthook runs quickly. I'm not sure if I even attempted it.

I think I've recovered most of changes using undoing, resulted in the changes reappearing.

[PaulRBerg]

Same class of failure here on Lefthook 2.1.9 while testing a Husky/lint-staged migration.

Repro shape: partially staged tracked file + mutating pre-commit formatter. Lefthook hid the unstaged patch, the formatter rewrote the same lines, then .git/info/lefthook-unstaged.patch could not be applied back cleanly. Removing stage_fixed did not prevent the hide/restore path in my test.

I could not find a simple “don’t hide unstaged changes” or “fail before mutating if partial staging is present” option. We wanted Lefthook to simplify hooks, but this pushed us toward avoiding Lefthook for pre-commit entirely.

A no-hide or fail-fast mode would make this much safer.

[Fydon]

The 2.1.7 release as improved things, with changes like the ones linked #1400, where earlier 2.1.x releases were causing issues for me constantly. I've not had an issue yet since that update, but haven't used 2.1.8. or 2.1.9 yet.