auto fix not visible after partial commit #888

aschleifer · 2026-04-30T12:46:36Z

aschleifer
Apr 30, 2026

I have a repository with several hk linters enabled. In this repository I have these two files:

a.json:

{
  "entries": [],
  "test": false
}

b.md:

# test document

this is just for testing

Now I change something in a.json which will trigger an auto fix and i change something in b.md:

diff --git a/a.json b/a.json
index 212bc54..43fb2e0 100644
--- a/a.json
+++ b/a.json
@@ -1,5 +1,5 @@
 {
   "entries": [
   ],
-  "test": true
+  "test": false
 }
diff --git a/b.md b/b.md
index 3db9211..16736e6 100644
--- a/b.md
+++ b/b.md
@@ -1,3 +1,3 @@
 # test document

-this is just for testing
+this is just for testing.

I then only add the changes for a.json and try to commit that:

$ git add a.json

$ git commit -m "chore: json update"
hk WARN  Files were modified by fix commands (fail_on_fix=true):
  a.json
hk 1.44.0 by @jdx – pre-commit – fix  [=================================================================================================================================================================================================================] 5/5
✔ files - Stashed unstaged changes (1 file)
✔ check-symlinks
✔ check-added-large-files
✔ jq
✔ newlines
✔ trailing-whitespace
✔ stash – Restoring unstaged changes (manual)
hk ERROR pre-commit: hook finished with error: fail_on_fix: files were modified by fix commands

Location:
    src/hook.rs:973:30
Error: fail_on_fix: files were modified by fix commands

Location:
    src/hook.rs:973:30

When I run a git status now I would expect the original changes of a.json to still be staged, but the auto fix to be unstaged and b.md also unstaged. Instead I find that the auto fix is just gone:

$ ╰─ git status
On branch test
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
        modified:   a.json

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
        modified:   b.md

$ git diff 
diff --git a/b.md b/b.md
index 3db9211..16736e6 100644
--- a/b.md
+++ b/b.md
@@ -1,3 +1,3 @@
 # test document

-this is just for testing
+this is just for testing.

jdx · 2026-04-30T13:33:21Z

jdx
Apr 30, 2026
Maintainer

Confirmed bug. The step's auto-staging was silently re-staging the fixer's output over your explicit git add choices, so the fix never appeared as an unstaged change for review and a re-commit would silently succeed with the fix baked in — defeating the point of fail_on_fix.

Fix in #892: when fail_on_fix=true, fix runs no longer stage their output. After the fix your scenario behaves as you described — original staged change preserved, jq's reformatting visible as an unstaged change, b.md untouched.

This comment was generated by Claude Code.

2 replies

aschleifer May 6, 2026
Author

@jdx sadly the fix had no effect. I see the same behavior as before. I did verify that I'm on 1.44.3

jdx May 6, 2026
Maintainer

I rebuilt your scenario on both v1.44.2 (pre-fix) and v1.44.3 (post-fix) — same hk.pkl, same files, same staging steps. The bug reproduces exactly on v1.44.2 and is fixed on v1.44.3.

v1.44.2 (broken — matches your report):

$ git status --short
M  a.json     # only staged — the fix was silently re-staged
 M b.md

$ git diff --cached a.json
-  "test": true
+  "test": false      # your intent...
   "entries": []      # ...silently merged with jq's reformatting

$ git diff a.json
(empty — fix is gone)

v1.44.3 (fixed):

$ git status --short
MM a.json     # staged: your original change | unstaged: jq's fix (visible for review)
 M b.md

$ git diff --cached a.json
   "entries": [
+  ],
-  "test": true
+  "test": false      # your original change preserved as-is

$ git diff a.json
-  "entries": [
-  ],
+  "entries": [],     # jq's reformatting now visible as unstaged

Your reported git status (single modified: a.json staged, no unstaged diff on a.json, fix gone) matches v1.44.2 1:1. So most likely the binary actually invoked at commit time isn't v1.44.3, even if your shell's hk --version says it is.

Could you run these from inside your repo and paste the output?

which hk
hk --version
git config --get-all hook.hk-pre-commit.command

If your hook command is mise x -- hk …, also run mise which hk to confirm what mise resolves to. The hook may be picking up an older binary from a different PATH than your interactive shell.

If those all confirm v1.44.3, please also paste:

the output of HK_LOG=debug git commit -m … for the failed commit
git status and git diff --cached a.json (the cached diff is the smoking gun) immediately after
your hk.pkl, especially the stash field if set, and echo $HK_STASH

That will tell us whether the fix landed but a different code path is bypassing it.

This comment was generated by Claude Code.

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