Submodules vs subtrees comparison in Git - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to add a Git submodule.

Git

git submodule [1] https://github.com/example/lib.git

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

Aadd

Bclone

Cinit

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'clone' instead of 'add' causes an error.

Using 'init' only initializes existing submodules.

The git submodule add command adds a new submodule to your repository.

2fill in blank

medium

Complete the command to pull changes for all submodules.

Git

git submodule [1] --recursive

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

Aclone

Badd

Cinit

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'init' only initializes submodules but does not update them.

Using 'clone' is not valid here.

The git submodule update --recursive command fetches and checks out the correct commits for all submodules.

3fill in blank

hard

Fix the error in the command to add a subtree at prefix 'lib'.

Git

git subtree [1] --prefix=lib https://github.com/example/lib.git main

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

Aclone

Bpull

Cadd

Dinit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pull' instead of 'add' causes errors.

Using 'clone' is not a valid subtree command.

The correct command to add a subtree is git subtree add.

4fill in blank

hard

Fill both blanks to complete the command that updates a subtree from remote 'origin' branch 'main'.

Git

git subtree [1] --prefix=lib [2] main

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

Apull

Bpush

Corigin

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping pull and push causes wrong behavior.

Using 'add' instead of 'pull' does not update the subtree.

The command git subtree pull --prefix=lib origin main updates the subtree from the remote repository.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps submodule names to their paths if they are initialized.

Git

{ [1]: [2] for [3] in submodules if submodules[[3]]['initialized'] }

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

Aname

Bsubmodules[name]['path']

Dsubmodules

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable name causes errors.

Not filtering initialized submodules includes unwanted entries.

This comprehension creates a dictionary with submodule names as keys and their paths as values, filtering only initialized submodules.

Practice

1. What is the main difference between Git submodules and Git subtrees?

easy

A. Submodules and subtrees are identical in how they manage external repositories.

B. Submodules copy external repositories; subtrees link them separately.

C. Submodules merge external repositories automatically; subtrees require manual merging.

D. Submodules link external repositories separately; subtrees copy them into your project.

Solution

1. Step 1: Understand submodules behavior

   Submodules keep external repositories linked but separate from the main project folder.

2. Step 2: Understand subtrees behavior

   Subtrees copy the external repository content directly into your project folder, making it part of your codebase.

3. Final Answer:

   Submodules link external repositories separately; subtrees copy them into your project. -> Option D

4. Quick Check:

   Submodules = separate links, Subtrees = copied content [OK]

Hint: Remember: submodules link, subtrees copy [OK]

Common Mistakes:

• Confusing which method copies code versus links it
• Thinking submodules merge code automatically
• Assuming subtrees keep repos separate

2. Which Git command correctly adds a submodule to your repository?

easy

A. git subtree add --prefix=folder_name repo_url branch

B. git submodule add repo_url folder_name

C. git add submodule repo_url folder_name

D. git clone --submodule repo_url folder_name

Solution

1. Step 1: Identify the correct syntax for adding a submodule

   The correct command is 'git submodule add' followed by the repository URL and the folder name.

2. Step 2: Verify other options

   git subtree add --prefix=folder_name repo_url branch is for subtrees, not submodules. git add submodule repo_url folder_name and git clone --submodule repo_url folder_name are invalid Git commands for adding submodules.

3. Final Answer:

   git submodule add repo_url folder_name -> Option B

4. Quick Check:

   Submodule add uses 'git submodule add' [OK]

Hint: Submodule add always starts with 'git submodule add' [OK]

Common Mistakes:

• Using 'git subtree add' for submodules
• Trying to add submodules with 'git add'
• Confusing clone options with submodule commands

3. Given the commands below, what will be the result after cloning a repository with a submodule?

git clone https://example.com/main-repo.git
cd main-repo
git submodule update --init --recursive

medium

A. Only the main repository is cloned; submodules remain empty folders.

B. The submodules are cloned but not initialized.

C. The main repository and all submodules are cloned and initialized.

D. The clone fails because submodules require separate cloning.

Solution

1. Step 1: Understand cloning with submodules

   Cloning the main repo alone does not fetch submodule content; submodules are empty initially.

2. Step 2: Use 'git submodule update --init --recursive'

   This command fetches and initializes all submodules recursively, filling their folders with content.

3. Final Answer:

   The main repository and all submodules are cloned and initialized. -> Option C

4. Quick Check:

   Submodule update with init fetches submodules [OK]

Hint: Run 'git submodule update --init --recursive' after clone [OK]

Common Mistakes:

• Assuming submodules clone automatically with main repo
• Skipping the submodule update command
• Confusing initialization with cloning

4. You added a subtree with git subtree add --prefix=lib https://example.com/lib.git main but later changes in the subtree are not reflected in your main repo. What is the likely cause?

medium

A. You forgot to pull subtree updates with git subtree pull.

B. Subtrees automatically sync changes; no action needed.

C. You must use git submodule update to sync subtrees.

D. Subtrees cannot be updated once added.

Solution

1. Step 1: Understand subtree update process

   Subtrees copy code but do not auto-sync; you must manually pull updates.

2. Step 2: Identify correct command to update subtree

   The command 'git subtree pull' fetches and merges changes from the external repo into your subtree folder.

3. Final Answer:

   You forgot to pull subtree updates with git subtree pull. -> Option A

4. Quick Check:

   Subtrees require manual pull to update [OK]

Hint: Use 'git subtree pull' to update subtree changes [OK]

Common Mistakes:

• Expecting automatic subtree sync
• Using submodule commands for subtrees
• Thinking subtrees are read-only

5. You want to include a third-party library in your project. You want to keep it separate for easy updates but also want your team to clone the project with one command without extra steps. Which approach is best?

hard

A. Use Git subtrees to copy the library into your project for simpler cloning.

B. Use Git submodules and instruct the team to run extra commands after cloning.

C. Manually copy the library files without Git integration.

D. Use Git submodules but disable recursive cloning.

Solution

1. Step 1: Analyze submodules pros and cons

   Submodules keep code separate but require extra commands after cloning to initialize submodules.

2. Step 2: Analyze subtrees pros and cons

   Subtrees copy the library into the project, so cloning is simple with one command and no extra steps.

3. Final Answer:

   Use Git subtrees to copy the library into your project for simpler cloning. -> Option A

4. Quick Check:

   Subtrees simplify cloning by embedding code [OK]

Hint: Subtrees = easy clone; submodules = extra steps [OK]

Common Mistakes:

• Choosing submodules despite extra clone steps
• Ignoring subtree benefits for team convenience
• Thinking manual copy is better than Git methods