돈을 아끼려고 세상에서 최악의 동기화 서비스인 Apple iCloud를 Obsidian Second Brain 동기화용으로 쓰는 사람으로서, 최근 이 문제를 정말 자주 겪고 있다:

$ git status
fatal: bad object HEAD
$ git log
fatal: bad object refs/heads/main

StackOverflow 최상위 답변은 10년 된 글인데 rm -rf .git 하라고 한다. 물론 그건 제대로 된 해결법이 아니다.

이걸 몇 번 고쳐야 했는데, 최근에야 ChatGPT와 함께 해결법을 찾았다. 후세를 위해 여기에 남겨둔다:

$ git fetch origin
# THIS USUALLY DOES IT FOR ME - then i can commit and merge and push normally

# hopefully this is good enough for git status to start working again
$ git pull

평소보다 더 심각하게 망가졌을 때

# confirm fuckedness

$ git fsck
bad sha1 file: .git/objects/00/084ad8182051c580009e8ccc22e224d97a4823 2
bad sha1 file: .git/objects/02/8027ce244a5390478159b510bd6767d648e31f 2
bad sha1 file: .git/objects/03/8c235cd6cc3e93596b25d7fb0ab14d9a999ec7 2
bad sha1 file: .git/objects/05/72e5490252d8fd25230669000747a7032a14df 2
bad sha1 file: .git/objects/07/ecafe1981e587022b562562ce02fd0adc45beb 2
bad sha1 file: .git/objects/09/e5b5f51f4f9683155f7a81d4fad1321e4085ee 2
bad sha1 file: .git/objects/0a/47019b78b8fd69a1b1a2d96b2be442fbceaf49 2
bad sha1 file: .git/objects/0c/b9400cec84abac87519225f7e5ceca987e7f66 2
bad sha1 file: .git/objects/10/2a21b02d2f08c777bfe0066de28afe0df3290c 2
bad sha1 file: .git/objects/14/e8edad8d4898bc04c4a00ce0df268cf359df63 2
bad sha1 file: .git/objects/14/65567afb6ee576ceb3e3061ffdf9c4ccd47095 2
bad sha1 file: .git/objects/1a/ac8cf84058d474b8845fe4ff410a2a1bc5a25a 2
bad sha1 file: .git/objects/1b/5cf76bb3a880fcf70083fda0aa4d0faccb5864 2

# etc etc etc

"2"가 잔뜩 보인다면 iCloud가 문제를 일으키고 있는 것이다. 이렇게 해결하자:

#  remove all files in .git with a space and then a number in their name, likely duplicates created by icloud
find .git -type f -name '* [0-9]*' -delete

그 다음 git fetch origin을 다시 실행하면 된다.

만약

$ git log
fatal: bad object refs/heads/main

이런 에러가 뜬다면

git update-ref -d refs/heads/main

기타 메모

# NOTE: THIS WILL DESTROY ANY UNCOMMITTED/UNSAVED CHANGES - take care before running it
$ git reset --hard origin/main

이 과정에서 bad object가 보일 수도 있다:

remote: Enumerating objects: 3899, done.
remote: Counting objects: 100% (888/888), done.
remote: Compressing objects: 100% (364/364), done.
remote: Total 3899 (delta 554), reused 597 (delta 523), pack-reused 3011
Receiving objects: 100% (3899/3899), 1.32 MiB | 9.92 MiB/s, done.
error: corrupt loose object 'dc3711cb3ba71eefe40c8e49cc9c9fb311d29553'
fatal: loose object dc3711cb3ba71eefe40c8e49cc9c9fb311d29553 (stored in .git/objects/dc/3711cb3ba71eefe40c8e49cc9c9fb311d29553) is corrupt
fatal: fetch-pack: invalid index-pack output
fatal: Could not parse object 'origin/main'.

해결법은 이렇다:

rm -f .git/objects/dc/3711cb3ba71eefe40c8e49cc9c9fb311d29553
git fetch origin

(7월 31일 업데이트) corrupt loose object

오늘도 이 문제가 발생했다:

$ git fsck

error: corrupt loose object '25726bffc0e97532098679d0ed04095710452d29'
error: unable to unpack contents of .git/objects/25/726bffc0e97532098679d0ed04095710452d29
error: 25726bffc0e97532098679d0ed04095710452d29: object corrupt or missing: .git/objects/25/726bffc0e97532098679d0ed04095710452d29
error: corrupt loose object '5b4e2ac94c33715545674545e501a705ea20924b'
error: unable to unpack contents of .git/objects/5b/4e2ac94c33715545674545e501a705ea20924b
error: 5b4e2ac94c33715545674545e501a705ea20924b: object corrupt or missing: .git/objects/5b/4e2ac94c33715545674545e501a705ea20924b
error: corrupt loose object 'ad7ceee5b187af409cbd2219bc4b578faf425471'
error: unable to unpack contents of .git/objects/ad/7ceee5b187af409cbd2219bc4b578faf425471
error: ad7ceee5b187af409cbd2219bc4b578faf425471: object corrupt or missing: .git/objects/ad/7ceee5b187af409cbd2219bc4b578faf425471
error: corrupt loose object 'fdacf1b391398e4548fa3a9f09b0f6714881907c'
error: unable to unpack contents of .git/objects/fd/acf1b391398e4548fa3a9f09b0f6714881907c
error: fdacf1b391398e4548fa3a9f09b0f6714881907c: object corrupt or missing: .git/objects/fd/acf1b391398e4548fa3a9f09b0f6714881907c
Checking object directories: 100% (256/256), done.
Checking objects: 100% (27396/27396), done.
missing blob 60e0633917e44a958f890039cff7297f99d8e8eb
dangling commit d885e9e214a1f84ce5feb8fdcdf51a27249e689e
dangling commit a38bc134bc0ec9741e7abbfa8ee200a0c82253d6
missing blob fdacf1b391398e4548fa3a9f09b0f6714881907c
missing blob 5b4e2ac94c33715545674545e501a705ea20924b
missing blob 25726bffc0e97532098679d0ed04095710452d29
missing blob f2f68aa9deda03f256574d468395e840144d9d05
missing blob ad7ceee5b187af409cbd2219bc4b578faf425471

온갖 기괴한 옵션들을 추천받았지만, 결국 해결법은 이거였다:

git reset <last good remote commit> # NOT hard!
git stash # to store stuff that has been changed since last good remote commit
git fetch origin # pull down everything since last commit
git stash pop # put back the new stuff
git add . && git commit -m "add back new stuff" # new stuff
git push origin main # done!