安全にミスを取り消す
AIの助けを借りて失った作業を復元します。
「安全にミスを取り消す」はCoddyKit上の無料Vibe Codingレッスンです。 これはレッスン4/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはVibe Coding学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Vibe Codingコースには全4レッスンが含まれています。
このレッスンの一部はまだ翻訳されておらず、英語で表示されています。
Mistakes Are Normal
Every builder breaks things. The difference between panic and calm is one thing: knowing you can undo it.
Because you've been committing along the way, your good work is saved. This lesson shows you how to recover from the most common "oh no" moments — with AI guiding you so you never make things worse.
Rule #1 of undoing: don't panic, don't randomly type commands. Ask AI first.
The First Question to Ask
Before undoing anything, figure out where your changes are. There are three places work can live:
- Unsaved — edited but not committed yet
- Committed — snapshotted but maybe you want to go back
- Pushed — already on GitHub
The right undo depends on which one. So always start by telling AI your exact situation.
Undo: Unsaved Changes
Most common case: you made changes (often AI made them), they broke things, and you haven't committed yet. You just want to go back to your last good commit.
This is the easiest recovery. Tell AI exactly this:
My last commit was working. Then I made changes that broke everything,
and I have NOT committed those bad changes.
I want to throw away all my uncommitted changes and go back to
exactly how things were at my last commit.
Give me the safe command to do that, and warn me about anything
I'll permanently lose.A Mental Model of Undo
Think of undo as choosing which save point to load. Run this to see the idea: you pick a known-good commit and discard everything after it.
const commits = ['Start', 'Add homepage', 'Add login (WORKS)', 'Break everything'];
let current = commits.length - 1;
console.log('You are here: ' + commits[current]);
const goodPoint = 2; // 'Add login (WORKS)'
current = goodPoint;
console.log('Reverting to: ' + commits[current]);
console.log('Your project is now back to a working state.');Undo: A Bad Commit
What if you already committed the broken change? You have two safe options, and AI will pick the right one:
- revert — creates a NEW commit that undoes the bad one (safe, keeps history)
- reset — moves you back, removing the bad commit (use with care)
For beginners, git revert is the gentle, reversible choice. It never erases history.
Revert vs Reset Prompt
Not sure which to use? Don't guess. Describe it and let AI choose the safest path:
I committed a change that broke my app. The bad commit is my most
recent one. I haven't pushed yet.
I'm a beginner and want the SAFEST way to undo just that one commit
without losing my earlier work. Should I use git revert or git reset?
Explain the difference simply, then give me the exact command.Recovering 'Lost' Work
Panic moment: "I think I deleted hours of work!" Usually, it's not actually gone. Git keeps a hidden safety log called the reflog that records nearly everything you did.
Even commits you thought you erased can often be brought back. Before you despair, ask AI to check the reflog:
I think I lost a bunch of work in Git -- maybe from a reset or a
branch I deleted. It might be gone.
Walk me through using `git reflog` to find my lost commits, and
then how to safely restore the one I need. Go one step at a time
and wait for me to paste the output before the next step.Undo One File Only
Sometimes you don't want to undo everything — just one file you messed up, while keeping your other changes.
Git can restore a single file to how it looked in any past commit. Describe exactly which file:
I have several files with changes I want to KEEP. But one file,
styles.css, got messed up and I want ONLY that file restored to
how it was in my last commit.
Give me the exact command to restore just styles.css, leaving
all my other changes untouched.The Safety Branch Trick
Before any scary undo, do this one thing: make a backup branch. It's a free insurance policy.
If the undo goes wrong, your backup branch still holds everything exactly as it was. Run this to see why it's reassuring:
let mainBranch = 'risky-state';
let backup = null;
// Before undoing, snapshot current state into a backup branch
backup = mainBranch;
console.log('Backup branch saved: ' + backup);
// Now experiment freely on main
mainBranch = 'after-undo';
console.log('Main branch now: ' + mainBranch);
console.log('If undo fails, restore from backup: ' + backup);When It's Already Pushed
If you already pushed the mistake to GitHub, undoing is still possible but needs a little more care so you don't confuse collaborators.
The safest move is almost always git revert (a new undo commit) followed by another push. Avoid rewriting pushed history unless AI tells you it's safe. Let AI handle the nuance:
I already pushed a broken commit to GitHub. Other people might be
using this repo.
What's the SAFEST way to undo it without messing up anyone else's
copy? I'm a beginner. Recommend revert vs reset for this case and
give me the exact commands.Your Calm Recovery Routine
Lock in this routine so mistakes never scare you again:
- Stop — don't randomly type commands
- Identify — unsaved, committed, or pushed?
- Backup — make a safety branch if it's risky
- Ask AI — describe the exact situation, get the safe command
- Verify — confirm the app works after
With commits as your save points and AI as your guide, there's almost no mistake you can't walk back.
Quick Check
You broke something. What's the smartest first move?
Recap & Course Wrap-Up
You can now recover from mistakes calmly:
- Identify where changes live: unsaved, committed, or pushed
- Discard uncommitted changes to return to your last good commit
- Use git revert for a gentle, reversible undo of a commit
- The reflog can rescue "lost" work
- Restore a single file, and make a backup branch before risky undos
That completes Version Control & Git with AI. You now save, organize, and recover your projects with confidence — and an AI helper at every step. Go build fearlessly.
よくある質問
「安全にミスを取り消す」レッスンは無料ですか？
はい。「安全にミスを取り消す」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Vibe Codingコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Vibe Codingコースには全4レッスンが含まれています。
「安全にミスを取り消す」で何を学びますか？
AIの助けを借りて失った作業を復元します。 ブラウザで直接実行するハンズオンコードでVibe Codingを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。
Vibe Codingを始めるのに経験は必要ですか？
事前経験は必要ありません。CoddyKitのVibe Codingは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン4/4です。
「安全にミスを取り消す」レッスンにはどのくらい時間がかかりますか？
ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。
このVibe Codingレッスンでコードを書いて実行できますか？
はい。すべてのVibe Codingレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。