Why merging combines work in Git - Visual Breakdown

Process Flow - Why merging combines work

Start: Two branches

↓

Make changes on branch A

↓

Commit changes on A

↓

Merge branch B into A

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Combine changes from both

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Resolve conflicts if any

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Final merged commit

Merging takes changes from two branches and combines them into one, preserving work from both sides.

Execution Sample

Git

git checkout main
# On main branch
# Make change and commit

git checkout feature
# On feature branch
# Make change and commit

git checkout main
git merge feature

This sequence switches branches, makes changes, commits them, then merges feature branch into main.

Process Table

Step	Action	Branch	Changes Present	Result
1	Checkout main	main	No new changes	On main branch
2	Make change and commit	main	Change A committed	Main branch updated
3	Checkout feature	feature	No new changes	On feature branch
4	Make change and commit	feature	Change B committed	Feature branch updated
5	Checkout main	main	Change A committed	Back on main branch
6	Merge feature into main	main	Changes A and B combined	Merged commit created
7	Check for conflicts	main	No conflicts	Merge successful

💡 Merge completes combining changes from both branches into main.

Status Tracker

Variable	Start	After Step 2	After Step 4	After Step 6	Final
main branch content	Initial code	Code + Change A	Code + Change A	Code + Change A + Change B	Code + Change A + Change B
feature branch content	Initial code	Initial code	Code + Change B	Code + Change B	Code + Change B

Key Moments - 3 Insights

Why does merging not overwrite changes from the main branch?

Because merging combines changes from both branches, preserving commits from main and feature as shown in step 6 of the execution_table.

What happens if both branches change the same line?

A conflict occurs that must be resolved manually before the merge completes, as noted in step 7 of the execution_table.

Why do we checkout main before merging?

Because merging applies changes into the current branch, so we switch to main to merge feature into it (step 5 and 6).

Visual Quiz - 3 Questions

Look at the execution_table, what changes are present on the main branch after step 2?

A No new changes

B Change A committed

C Change B committed

D Changes A and B combined

💡 Hint

Check the 'Changes Present' column at step 2 in the execution_table.

At which step does the merge combine changes from both branches?

A Step 4

B Step 3

C Step 6

D Step 7

💡 Hint

Look for the step where 'Changes A and B combined' appears in the execution_table.

If a conflict occurs during merge, which step would show this in the execution_table?

A Step 7

B Step 6

C Step 5

D Step 2

💡 Hint

Step 7 checks for conflicts according to the execution_table.

Concept Snapshot

git merge combines changes from two branches into one.
Switch to the branch you want to update (e.g., main).
Run 'git merge <branch>' to combine work.
If changes overlap, resolve conflicts manually.
Merge preserves history from both branches.

Full Transcript

Merging in git means combining work from two branches. First, you have two branches, each with their own changes. You commit changes on each branch separately. Then, you switch to the branch you want to update, usually main. Running 'git merge feature' takes the changes from the feature branch and adds them to main. If both branches changed different parts, git combines them automatically. If they changed the same lines, git asks you to fix conflicts. After resolving conflicts, the merge finishes and you have one branch with all combined work.