Ohh shit git

Think ahead. Act now.
Jesse Houwing
Tinkerer, trainer, coach
@jessehouwing
xpirit.com/jesse

Oh Sh*t - Basics

Ohh sh*t I made a typo in the commit message
git commit --amend -m “Centrum"

Ohh sh*t I forgot to add a file to my commit
git add file2.txt
git commit --amend --no-edit

Ohh sh*t I want to undo my change, but already
pushed it.
git revert <<commit>>
git push

Ohh sh*t I totally messed up everything.
del /s /q /a /f .
git clone <your remote>
https://xkcd.com/1597/

Ohh sh*t I totally messed up my repo and want to
keep my changes
Copy everything to a safe location
git clone <<your repo>>
git checkout -b fixbranch
Clear the folder
Paste the contents of your old repo (except the .git folder)
git add -A
git commit -m "Restored local changes!"

Ohh sh*t I want to clean up my changes before I
share them

Ohh sh*t I want to clean up my changes before I
share them
git rebase -i <<commit to start cleanup from>>
https://xkcd.com/1296/

Why force pushing is BAD
It messes up the work of others

Ohh Sh*t someone force pushed my parent
branch!

branch!
Not all is lost.
Try:
git pull –rebase
Or
git fetch origin/thatbranch
git rebase –onto origin/thatbranch

branch!
That failed huh?
Find the new hash <C> of the commit you last pulled
git rebase --onto origin/master <C> master

A B C
master
D
origin/master
Local
A BX
master
Remote
Find B

A B C
master
D
Local
BX
origin/master
Fetch origin/master

A B C
master
D
Local
BX CX DX
origin/master
rebase --onto origin/master <B> master
master

Ohh sh*t! Reset! Reset! Reset!

Let’s dig into reset
git reset --mixed (default)
• Move back in history
• Keep all changes in the working directory area.
git reset --soft
• Keeps the working directory, has all the changes staged.
git reset --hard & git clean -df
• Reverts all changes
• Removes all files and folders that are not tracked by git

git reset --mixed B
A B C
Stagin
g area
Work
dir
master
A B C
Stagin
g area
Work
dir
master

git reset --hard B
A B C
Stagin
g area
Work
dir
master
A B C
Stagin
g area
Work
dir
master

Ohh sh*t I totally messed but my repo is still
working.
Go back to the last time you pulled
git reset –hard
Go back to a specific commit
git reflog
Find the last known good commit
git reset --hard <<hash>>

Ohh sh*t I committed to the wrong branch

Ohh sh*t I committed to the wrong branch
git reset HEAD~1 --soft
git stash
git checkout right-branch
git stash pop
git add .
git commit -m

A B C
D
right
wrong
stash

stash
A B
C
D
right
wrong

stash
A B
C2D
right
wrong

Ohh sh*t I need to move more than one commit

Ohh sh*t I need to move more than one commit
git log
Note the hashes you want to move
git checkout <<right>>
git cherry-pick <<oldest-hash>>..<<latest-hash>>
git checkout <<wrong>>
git reset --hard <<oldest-hash>>^

A B C
E
right
wrong
D

A B C
E
right
wrong
D
C’ D’
git checkout right
git cherry-pick C..D

A
B
= C^
C
E
right
wrong
D
C’ D’
git checkout wrong
git reset --hard C^

Ohh sh*t I only need a single file from another
branch

This is hard
Because git assumes commits, not files.

Ohh sh*t I only need a single file from another
branch
I need the file as-is, ignore other changes
git checkout other-branch -- the-file-I-need.txt
I need specific changes from the other file
git checkout --patch other-branch -- the-file-I-need.txt
git cherry-pick <<hash>>
git reset --mixed
git add <<file to keep>>
git commit -m “cherry-picked one file” <<file to commit>>
git reset --hard

Ohh sh*t I need to delete all references to a file

On linux:
git filter-branch --index-filter 'git rm --cached --ignore-unmatch
filename' HEAD
On windows:
All examples are broken due to missing utilities, quoting issues,
powershell interference and other nonsense.

Ahhh! The BFG Repo-Cleaner!

Start with a fresh mirror clone
git clone --mirror git://example.com/some-big-repo.git

git rm <<file(s) to get rid of>>
git commit -m “remove safeties”
java -jar ..bfg-1.13.0.jar --delete-files <<files to get rid of>>

Ohh sh*t I need to remove a password
git rm <<file(s) to get rid of>>
git commit -m “remove safeties”
java -jar ..bfg-1.13.0.jar --replace-text passwords.txt my-repo.git

Then force your changes
git reflog expire --expire=now --all && git gc --prune=now –
aggressive
git push --all -force
git push --tags -force

Important note
Services will not delete the object from their storage/database
To permanently get rid of the files for real:
CREATE A NEW REPO.

It’s easy to make mistakes
And a 100 ways to solve them
Visual Studio doesn’t support them all…

But we’ve seen it’s easy to
Fix the last commit
Revert a change
Move changes from one branch to another
Rewrite history
Make our co-workers miserable
Help them recover
As long as you know what you’re doing…

Cheat Sheet

Ohh shit git

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