post-merge hook in Git - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a post-merge hook script that prints a message after merging.

Git

#!/bin/sh
 echo "[1]"

Drag options to blanks, or click blank then click option'

AMerge completed successfully!

Bgit merge

Cmerge finished

Dpost-merge hook

Attempts:

3 left

💡 Hint

Common Mistakes

Using git commands inside the hook without proper syntax.

Not making the script executable.

Printing nothing or an unclear message.

The post-merge hook script runs after a merge. Printing a message like "Merge completed successfully!" confirms the merge.

2fill in blank

medium

Complete the code to make the post-merge hook executable.

Git

chmod [1] .git/hooks/post-merge

Drag options to blanks, or click blank then click option'

A777

B644

C-x

D+x

Attempts:

3 left

💡 Hint

Common Mistakes

Using numeric permissions instead of symbolic.

Using '-x' which removes execute permission.

Not setting executable permission at all.

The post-merge hook script must be executable. Using chmod +x sets the executable permission.

3fill in blank

hard

Fix the error in the post-merge hook script to correctly run a command after merge.

Git

#!/bin/sh
 git [1]

Drag options to blanks, or click blank then click option'

Apush

Bcommit

Cstatus

Dmerge

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to run 'git merge' inside the post-merge hook.

Running 'git push' which may cause unexpected behavior.

Running 'git commit' without staged changes.

After a merge, running git status shows the current state. Using git merge inside post-merge causes errors.

4fill in blank

hard

Fill both blanks to write a post-merge hook that updates submodules and prints a message.

Git

#!/bin/sh
 git [1] --recursive
 echo "[2]"

Drag options to blanks, or click blank then click option'

Asubmodule update

Bsubmodule init

CSubmodules updated successfully!

DMerge completed

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'submodule init' instead of 'submodule update'.

Not printing any message after updating.

Forgetting the --recursive option.

The post-merge hook can update submodules with git submodule update --recursive and then print a success message.

5fill in blank

hard

Fill all three blanks to create a post-merge hook that logs the merge time, updates submodules, and prints a message.

Git

#!/bin/sh
 echo "Merge done at $(date)" >> merge.log
 git [2] --recursive
 echo "{{BLANK_3}}"

Drag options to blanks, or click blank then click option'

Adate

Bsubmodule update

CSubmodules updated successfully!

Dgit status

Attempts:

3 left

💡 Hint

Common Mistakes

Not logging the date correctly.

Using wrong git commands for submodules.

Not printing a confirmation message.

This script logs the current date and time to merge.log, updates submodules recursively, and prints a success message.

Practice

1. What is the main purpose of the post-merge hook in Git?

easy

A. To create a new branch after merging

B. To prevent merges from happening

C. To delete merged branches automatically

D. To run commands automatically after a merge completes

Solution

1. Step 1: Understand the role of Git hooks

   Git hooks are scripts that run at specific points in Git workflows to automate tasks.

2. Step 2: Identify the specific timing of the post-merge hook

   The post-merge hook runs right after a merge finishes, allowing automation of follow-up tasks.

3. Final Answer:

   To run commands automatically after a merge completes -> Option D

4. Quick Check:

   post-merge hook = runs after merge [OK]

Hint: Post-merge hook runs after merge finishes [OK]

Common Mistakes:

• Confusing post-merge with pre-merge hooks
• Thinking it prevents merges
• Assuming it creates or deletes branches

2. Which of the following is the correct way to make a post-merge hook script executable on a Unix-like system?

easy

A. chmod 777 .git/hooks/post-merge

B. chmod +x .git/hooks/post-merge

C. git hook enable post-merge

D. chmod 644 .git/hooks/post-merge

Solution

1. Step 1: Understand file permissions for executable scripts

   To run a script as a hook, it must have executable permission, usually set with chmod +x.

2. Step 2: Identify the correct command

   chmod +x .git/hooks/post-merge sets the executable bit without giving excessive permissions.

3. Final Answer:

   chmod +x .git/hooks/post-merge -> Option B

4. Quick Check:

   Make hook executable = chmod +x [OK]

Hint: Use chmod +x to make hook executable [OK]

Common Mistakes:

• Using chmod 777 which is insecure
• Using chmod 644 which is not executable
• Trying git commands to enable hooks

3. Given this post-merge hook script saved in .git/hooks/post-merge and made executable:

#!/bin/sh
npm install
npm run build

What will happen after you run git merge feature-branch?

medium

A. The dependencies will install and the project will build automatically

B. The merge will fail because of the script

C. Nothing happens because post-merge hooks do not run automatically

D. Only npm install will run, not npm run build

Solution

1. Step 1: Understand what the post-merge hook script does

   The script runs npm install to install dependencies, then npm run build to build the project.

2. Step 2: Know when the post-merge hook runs

   It runs automatically after a successful merge, so both commands will execute in order.

3. Final Answer:

   The dependencies will install and the project will build automatically -> Option A

4. Quick Check:

   post-merge runs script after merge [OK]

Hint: Post-merge runs script commands after merge [OK]

Common Mistakes:

• Thinking hooks don't run automatically
• Assuming only first command runs
• Believing merge fails due to hook

4. You wrote a post-merge hook script but it does not run after merging. Which of these is the most likely cause?

medium

A. The script file is not executable

B. You forgot to commit the hook script

C. The merge was done with git rebase

D. The script is saved outside the .git/hooks directory

Solution

1. Step 1: Check script execution permissions

   If the script is not executable, Git will not run it after merge.

2. Step 2: Understand that hooks are local and not committed

   Hooks are not shared via commits, so forgetting to commit is irrelevant.

3. Step 3: Consider merge method and script location

   Rebase does not trigger post-merge, but the question states a merge was done. Also, hooks must be in .git/hooks.

4. Final Answer:

   The script file is not executable -> Option A

5. Quick Check:

   Non-executable script = hook won't run [OK]

Hint: Check if hook script has executable permission [OK]

Common Mistakes:

• Thinking hooks are shared via commits
• Confusing merge with rebase triggers
• Saving script outside .git/hooks folder

5. You want to ensure that after every merge, your Python project automatically installs new dependencies listed in requirements.txt and runs tests. Which post-merge hook script is the best choice?

hard

A. #!/bin/sh
git pull
pytest

B. #!/bin/sh
npm install
npm test

C. #!/bin/sh
pip install -r requirements.txt
pytest

D. #!/bin/sh
pip uninstall -r requirements.txt
pytest

Solution

1. Step 1: Identify the correct commands for Python dependency installation and testing

   pip install -r requirements.txt installs dependencies; pytest runs tests.

2. Step 2: Evaluate other options for relevance

   #!/bin/sh npm install npm test uses npm commands for JavaScript, not Python. #!/bin/sh pip uninstall -r requirements.txt pytest uninstalls dependencies which is wrong. #!/bin/sh git pull pytest pulls changes again, unnecessary after merge.

3. Final Answer:

   #!/bin/sh pip install -r requirements.txt pytest -> Option C

4. Quick Check:

   Python post-merge = pip install + pytest [OK]

Hint: Use pip install and pytest for Python post-merge tasks [OK]

Common Mistakes:

• Using npm commands for Python projects
• Uninstalling dependencies instead of installing
• Running git pull again after merge