Git Internals

Hooks and policy enforcement

Use local and server-side hooks with clear responsibility boundaries to turn collaboration policy from convention into enforcement.

Written by Lance MQ · 12 years of Git

Who This Is For

Readers building a durable Git mental model
Developers who keep running into history, ref, or recovery confusion

Prerequisites

Comfort reading basic Git output
A rough idea of commits, branches, and HEAD

Common Risks

Learning low-level terms without connecting them to commands
Collapsing objects, refs, and working state into one concept

Citations & Further Reading

Githooks [Official]
Git commit [Official]
Git push [Official]

What you will learn

Understand the core purpose of Hooks and policy enforcement
Master the basic usage and common options of Hooks and policy enforcement
Use local and server-side hooks with clear responsibility boundaries to turn collaboration policy from convention into enforcement.
Understand key concepts: Two hook classes
Know when to use this feature and when to avoid it

Git hooks let teams attach automation and policy checks to commit and push lifecycle events.

Start with a problem

You use Git commands daily, but occasionally encounter 'strange' behavior — like being told a file changed when you didn't touch it, or unexpected conflicts during a rebase. You want to understand how Git works under the hood.

Two hook classes

local hooks: execute on developer machines
server hooks: execute when remote receives pushes

Hook Execution FlowGit hooks execute scripts on specific event triggers, the lowest-cost way to enforce local policies.

Trigger Events

pre-commitprepare-commit-msgpost-checkout

Policy Checks

Code styleCommit messageBranch naming

Client-side hooks can be bypassed. Do not rely on them as the only security line.

Responsibility split

local hooks for fast feedback (formatting, quick lint)
server hooks for mandatory governance (branch rules, policy gates)

Common enforcement targets

commit-message policy
protected-branch direct-push restrictions
required issue/change-ticket reference

Practical rule

Put advisory checks locally and mandatory checks server-side.

Local-only hooks cannot guarantee team policy

Local hooks can be skipped or inconsistent. Critical controls must be enforced centrally.

Good follow-up reads

Try it yourself

Practice the hooks-and-policy-enforcement command in a test repository and observe state changes before and after
Experiment with different options and compare the output differences
Simulate a real scenario where you would need to use this, and walk through the full process

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