Reading conflict markers in Git - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are conflict markers in Git?

Conflict markers are special lines Git adds to files when it can't automatically merge changes. They show where the conflicts are so you can fix them.

beginner

Identify the three parts of a Git conflict marker.

The three parts are: <<<<<<< HEAD (your changes), ======= (separator), and >>>>>>> branch-name (incoming changes).

beginner

What does the line starting with <<<<<<< mean in a conflicted file?

It marks the start of your current branch's version of the conflicting code.

beginner

What should you do after seeing conflict markers in your file?

You should read the conflicting sections, decide which code to keep or combine, remove the conflict markers, and then save the file.

beginner

Why does Git add conflict markers instead of merging automatically?

Git adds conflict markers when it can't decide which changes to keep because both branches changed the same part of the file differently.

What does the ======= line in a Git conflict marker separate?

A Two unrelated files

B The start and end of the file

C The commit message and the code

D Your changes and the incoming changes

The ======= line separates your current branch's changes from the incoming branch's changes.

Which marker shows the incoming branch's changes in a conflict?

A <<<<<<< HEAD

B >>>>>>> branch-name

C =======

D # Conflict start

The >>>>>>> branch-name marker shows the incoming branch's conflicting changes.

What is the first step to resolve a Git conflict after seeing conflict markers?

A Read and understand the conflicting sections

B Delete the file

C Commit the file immediately

D Run git push

You must first read and understand the conflicting sections before deciding how to fix them.

If you want to keep only your changes in a conflict, what should you do?

A Keep all code including markers

B Keep the code after =======

C Keep the code between <<<<<<< HEAD and =======, remove the rest

D Delete the entire file

To keep your changes, keep the code between <<<<<<< HEAD and ======= and remove the rest including markers.

Why might Git not be able to merge automatically?

A Because both branches changed the same lines differently

B Because the commit messages are missing

C Because the internet is slow

D Because the files are too large

Git cannot merge automatically when both branches changed the same lines in different ways.

Explain what conflict markers look like in a Git file and what each part means.

Think about how Git shows your version and the other branch's version.

Describe the steps you take to resolve a file with Git conflict markers.

Focus on understanding, editing, and finalizing the file.

Practice

1. What do conflict markers in a Git file indicate?

easy

A. They show where changes from different branches clash in the file.

B. They mark lines that are deleted permanently.

C. They highlight syntax errors in the code.

D. They indicate lines that are ignored by Git.

Solution

1. Step 1: Understand the purpose of conflict markers

   Conflict markers appear when Git cannot automatically merge changes from different branches.

2. Step 2: Identify what conflict markers show

   They highlight the exact lines where changes from two sources conflict, so you can decide how to fix them.

3. Final Answer:

   They show where changes from different branches clash in the file. -> Option A

4. Quick Check:

   Conflict markers = show clashes [OK]

Hint: Conflict markers always show merge clashes in files [OK]

Common Mistakes:

• Thinking conflict markers show deleted lines
• Confusing conflict markers with syntax errors
• Believing conflict markers mark ignored lines

2. Which of the following is the correct way conflict markers appear in a Git file?

easy

A. >>>>>> HEAD
Your changes here
======
Incoming changes here
<<<<<<< branch-name

B. <<<<<<< HEAD
Your changes here
=======
Incoming changes here
>>>>>>> branch-name

C. <<<<<<< branch-name
Incoming changes here
=======
Your changes here
>>>>>>> HEAD

D. ======
Your changes here
<<<<<<< HEAD
Incoming changes here
>>>>>>> branch-name

Solution

1. Step 1: Recall the standard conflict marker format

   Git uses <<<<<<< HEAD to start your changes, ======= to separate, and >>>>>>> branch-name to end.

2. Step 2: Match the correct sequence

   <<<<<<< HEAD Your changes here ======= Incoming changes here >>>>>>> branch-name matches this exact format with your changes first, separator, then incoming changes.

3. Final Answer:

   <<<<<<< HEAD Your changes here ======= Incoming changes here >>>>>>> branch-name -> Option B

4. Quick Check:

   Conflict markers start with <<<<<<< HEAD [OK]

Hint: Conflict markers start with <<<<<<< HEAD and end with >>>>>>> branch-name [OK]

Common Mistakes:

• Swapping HEAD and branch-name positions
• Using wrong number of < or > symbols
• Mixing up the order of your and incoming changes

3. Given this conflict marker snippet in a file:

<<<<<<< HEAD
int x = 5;
=======
int x = 10;
>>>>>>> feature-branch

What will be the value of x after you manually choose the incoming change and save?

medium

A. 15

B. 5

C. 10

D. Conflict remains, no value assigned

Solution

1. Step 1: Identify the incoming change section

   The incoming change is after the ======= marker, which is int x = 10;.

2. Step 2: Understand manual conflict resolution

   Choosing the incoming change means keeping int x = 10; and removing conflict markers.

3. Final Answer:

   10 -> Option C

4. Quick Check:

   Incoming change value = 10 [OK]

Hint: Incoming changes are after ======= marker [OK]

Common Mistakes:

• Choosing the code before ======= instead of after
• Leaving conflict markers in the file
• Assuming both values apply simultaneously

4. You see this conflict marker in your file:

<<<<<<< HEAD
console.log('Hello');
=======
console.log('Hi');
>>>>>>> update-branch

After editing, you accidentally leave the conflict markers in the file and commit. What problem will this cause?

medium

A. The conflict markers will be ignored and code runs fine.

B. Git will automatically fix the conflict on next pull.

C. Git will delete the file on next merge.

D. The code will have syntax errors and may not run.

Solution

1. Step 1: Understand what conflict markers are

   Conflict markers are not valid code; they are special symbols for humans to resolve conflicts.

2. Step 2: Effect of leaving markers in code

   If left in the file, the code will have syntax errors and likely fail to run or compile.

3. Final Answer:

   The code will have syntax errors and may not run. -> Option D

4. Quick Check:

   Leaving markers = syntax errors [OK]

Hint: Remove conflict markers before committing to avoid errors [OK]

Common Mistakes:

• Assuming Git fixes conflicts automatically after commit
• Thinking conflict markers are comments
• Believing code runs fine with markers present

5. You have this conflict in a file:

<<<<<<< HEAD
function greet() {
  return 'Hello';
}
=======
function greet() {
  return 'Hi';
}
>>>>>>> feature

You want to combine both greetings so the function returns both messages separated by a comma. How should you edit the file to resolve the conflict correctly?

hard

A. Replace the conflict markers with:
function greet() {
return 'Hello, Hi';
}

B. Keep only the HEAD version:
function greet() {
return 'Hello';
}

C. Keep only the feature version:
function greet() {
return 'Hi';
}

D. Leave the conflict markers and both versions as is.

Solution

1. Step 1: Understand the goal to combine greetings

   You want the function to return both messages, so you must merge the changes manually.

2. Step 2: Edit the file by removing conflict markers and combining lines

   Replace the conflict markers and both versions with a single function returning 'Hello, Hi'.

3. Final Answer:

   Replace the conflict markers with: function greet() { return 'Hello, Hi'; } -> Option A

4. Quick Check:

   Combine changes by editing and removing markers [OK]

Hint: Edit conflict markers out and combine code as needed before commit [OK]

Common Mistakes:

• Leaving conflict markers in the file
• Choosing only one version without combining
• Not saving changes before committing