Git bisect

git bisect helps identify the exact commit that introduced a bug by efficiently searching through commit history.

• Uses a binary search approach to narrow down problematic commits.
• Marks commits as good or bad during testing.
• Automatically selects the next commit to test.
• Quickly pinpoints the commit that caused a regression.

Implementation of Git bisect command

Assume a repository contains a regression. The following steps outline the technical procedure for using git bisect to identify the faulty commit:

Step 1: Start the bisect process

Initialize the bisect session:

git bisect start

Step 2: Mark the current commit as bad

Assume HEAD is the bad commit.

git bisect bad

Step 3: Identify a known good commit

Specify a commit where the bug did not exist:

git bisect good <good_commit_hash>

Step 4: Test each commit

• Git will now check out a commit in the middle of the range. Run your tests:
• Run your test command

./run-tests.sh  

• If the tests fail (bug is present):

git bisect bad

• If the tests pass (bug is not present):

git bisect good

Step 5: Repeat until you find the offending commit

Git will continue to provide you with commits to test. Follow the previous step until you see a message indicating which commit introduced the bug.

Output:

git bisect efficiently finds the commit that introduced a bug by using binary search, making debugging faster and more manageable in large projects.