debugging

There comes a time in every developer’s life when you just know a certain commit existed. You remember its hash: deadbeef1234. You remember what it did. You know it was important. And yet, when you go looking for it…

💥 fatal: unable to read tree <deadbeef1234>

Great. Git has ghosted you.

That was me today. All I had was a lonely commit hash. The branch that once pointed to it? Deleted. The local clone that once had it? Gone in a heroic but ill-fated attempt to save disk space. And GitHub? Pretending like it never happened. Typical.

🪦 Act I: The Naïve Clone

“Let’s just clone the repo and check out the commit,” I thought. Spoiler alert: that’s not how Git works.

git clone --no-checkout https://github.com/user/repo.git
cd repo
git fetch --all
git checkout deadbeef1234

🧨 fatal: unable to read tree 'deadbeef1234'

Thanks Git. Very cool. Apparently, if no ref points to a commit, GitHub doesn’t hand it out with the rest of the toys. It’s like showing up to a party and being told your friend never existed.

🧪 Act II: The Desperate fsck

Surely it’s still in there somewhere? Let’s dig through the guts.

git fsck --full --unreachable

Nope. Nothing but the digital equivalent of lint and old bubblegum wrappers.

🕵️ Act III: The Final Trick

Then I stumbled across a lesser-known Git dark art:

git fetch origin deadbeef1234

And lo and behold, GitHub replied with a shrug and handed it over like, “Oh, that commit? Why didn’t you just say so?”

Suddenly the commit was in my local repo, fresh as ever, ready to be inspected, praised, and perhaps even resurrected into a new branch:

git checkout -b zombie-branch deadbeef1234

Mission accomplished. The dead walk again.

☠️ Moral of the Story

If you’re ever trying to recover a commit from a deleted branch on GitHub:

1. Cloning alone won’t save you.
2. git fetch origin <commit> is your secret weapon.
3. If GitHub has completely deleted the commit from its history, you’re out of luck unless:
   • You have an old local clone
   • Someone forked the repo and kept it
   • CI logs or PR diffs include your precious bits

Otherwise, it’s digital dust.

🧛 Bonus Tip

Once you’ve resurrected that commit, create a branch immediately. Unreferenced commits are Git’s version of vampires: they disappear without a trace when left in the shadows.

git checkout -b safe-now deadbeef1234

And there you have it. One undead commit, safely reanimated.