Branch protection rules in Git - Step-by-Step Execution

Process Flow - Branch protection rules

Start: Create branch

↓

Set branch protection rules

↓

Push or PR to branch

↓

Check rules: Is push/merge allowed?

No→Block action, show error

Yes↓

Allow push/merge

↓

Branch updated

This flow shows how branch protection rules check every push or merge to a branch and block it if rules are not met.

Execution Sample

Git

git branch main
# Set protection: require PR review
# Try to push directly to main
# Push blocked by protection
# Create PR and get review
# Merge PR to main

This example shows setting a branch protection rule on 'main' and how direct pushes are blocked, requiring a pull request with review.

Process Table

Step	Action	Branch	Protection Rule Check	Result	Message
1	Create branch	main	No check needed	Branch created	Branch 'main' created locally
2	Set protection rule	main	Require PR review before merge	Rule set	Branch protection rule applied to 'main'
3	Attempt direct push	main	Check direct push allowed?	Blocked	Push rejected: direct push not allowed, PR required
4	Create pull request	main	PR created	Pending review	Pull request opened for 'main'
5	Review PR	main	Check review approval	Approved	PR approved by reviewer
6	Merge PR	main	Check merge allowed	Merged	PR merged into 'main' branch

💡 Direct push blocked at step 3 due to branch protection requiring PR review

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 5	Final
branch_protection	none	require PR review	require PR review	require PR review	require PR review
branch_state	created	created	push blocked	PR approved	merged
push_allowed	true	false	false	false	false
pr_status	none	none	none	approved	merged

Key Moments - 3 Insights

Why is the direct push blocked even though the branch exists?

Because the branch protection rule set at step 2 requires pull request review before merging, so direct pushes are not allowed as shown in step 3.

What happens if the pull request is not approved?

The merge will be blocked at step 6 because the protection rule requires approval, so the branch state remains unchanged until approval.

Can you push directly after the PR is merged?

No, direct pushes remain blocked by the branch protection rule. All changes must go through pull requests with reviews.

Visual Quiz - 3 Questions

Look at the execution table, what is the result of the direct push attempt at step 3?

A Blocked with error message

B Allowed and branch updated

C Ignored silently

D Push queued for later

💡 Hint

Check the 'Result' and 'Message' columns at step 3 in the execution table

At which step does the branch protection rule get applied?

A Step 1

B Step 4

C Step 2

D Step 6

💡 Hint

Look at the 'Action' and 'Protection Rule Check' columns in the execution table

If the PR was not approved, what would be the branch state after step 5?

A merged

B PR open but not approved

C push blocked

D PR approved

💡 Hint

Refer to the 'pr_status' variable in the variable tracker after step 5

Concept Snapshot

Branch protection rules prevent direct pushes or merges that don't meet set conditions.
Common rules include requiring PR reviews, status checks, or restricting who can push.
When a rule blocks an action, Git rejects the push or merge with a clear message.
To update protected branches, follow the rules: create PRs, get reviews, then merge.
This keeps important branches safe and stable.

Full Transcript

Branch protection rules are settings on Git branches that control how changes can be made. The flow starts with creating a branch, then setting protection rules like requiring pull request reviews. When someone tries to push directly to the protected branch, Git checks the rules and blocks the push if it doesn't meet them. Instead, the user creates a pull request, which must be reviewed and approved. After approval, the pull request can be merged, updating the branch. Variables like branch protection status, push permission, and pull request state change step-by-step during this process. Key points include understanding why direct pushes are blocked and how approvals enable merges. This ensures the branch stays stable and changes are reviewed.