Git History & Forensics Vocabulary Exercises

1 / 5

A senior developer says: "We used git bisect to find the commit that introduced the regression."

What does git bisect do?

git bisect — binary search for regression commits:

Step	Command
1. Start	`git bisect start`
2. Mark current as broken	`git bisect bad`
3. Mark known-good commit	`git bisect good <SHA>`
4. Git checks out midpoint	Test and label good/bad — repeat until culprit found

Key vocabulary: binary search in history, regression bisect, bisect automation with test script, first bad commit.

2 / 5

An engineer says: "I ran git blame on that function to understand why it was changed."

What does git blame show?

git blame <file> — line-by-line authorship annotation:

Information shown per line	Use
Commit SHA	Run `git show <SHA>` for full context
Author name	Know who to ask about the code
Date	Understand when the change was made

Key vocabulary: line annotation, authorship attribution, code archaeology, git log -p (commit history with patches), using git blame for understanding, not blame.

3 / 5

A release note says: "The fix was cherry-picked from the hotfix branch to the release branch."

What does git cherry-pick do?

git cherry-pick — applying specific commits across branches:

Use case	Example
Apply security fix to multiple release branches	Cherry-pick the fix commit onto v1.x, v2.x branches
Selective backport	Take only one feature commit from main to release

Cherry-pick creates a new commit with a new SHA. Key vocabulary: apply changes from commit, new commit SHA, cherry-pick conflict, backport pattern.

4 / 5

A developer says: "I accidentally force-pushed and lost commits — I used git reflog to recover them."

What is the reflog?

git reflog — your local safety net:

Recovery scenario	Reflog recovery
Accidental `git reset --hard`	`git reflog` → find SHA → `git checkout <SHA>`
Deleted branch accidentally	Find last commit SHA in reflog → recreate branch
Force-push overwrote remote	Reflog has the pre-push HEAD position

Reflog keeps entries for ~90 days locally. Key vocabulary: HEAD history, dangling commit, reflog expiry (90 days), recovery after reset, lost commit retrieval.

5 / 5

A developer says: "I amended the last commit before pushing to fix a typo in the commit message."

What does git commit --amend do and when should it NOT be used?

git commit --amend — safe only before pushing:

State	Safe to amend?
Commit not yet pushed	✓ Safe — no one else has the old SHA
Commit pushed to personal branch (no one pulled)	✓ Safe with `--force-with-lease`
Commit pushed to shared/protected branch	✗ Dangerous — breaks collaborators who already pulled

Key vocabulary: commit amendment, history rewrite, force push danger on shared branches, amend before push.