Visual Git Deep Dive: The Object Graph, Refs, and How Commits Actually Work
See the Invisible
Interactive simulators visualize what's hidden from view.
Hands-On Labs
Step through executions tick by tick. Manipulate state.
Why, Not Just What
Deep architectural understanding for mid-senior developers.
AI Sandbox Lab
Real-world scenarios. Find the flaws AI misses.
Become the Engineer Who Supervises AI
As AI generates more code, understanding what that code does becomes more valuable, not less. Someone must verify AI output, debug failures, and make architectural decisions.
Build Your Architectural EdgeStop Memorizing Git Commands. Start Understanding What They Do.
You've used Git for years. You can commit, branch, merge, and rebase. But when something goes wrong, you're asking ChatGPT for flags or copying commands you don't fully trust. That uncertainty comes from a gap: you know the commands but not the machinery underneath.
The Knowledge Gap Holding You Back
You run
git reset --hard
and pray nothing important disappears. You don't know
what "hard" actually resets versus "soft" or "mixed."
"Detached HEAD state" triggers panic. You're not sure where your commits go or how to recover them if you checkout somewhere else.
"Don't rebase shared branches" is a rule you follow without understanding why. You can't explain what rebase actually does to commits at the object level.
You can't predict whether a merge will fast-forward or create a merge commit. The graph structure that determines this remains invisible to you.
See What's Invisible: Interactive Simulators for Git's Object Graph
Reading about blobs, trees, and parent pointers is one thing. Watching them form in real-time as you build commits is another. This course uses custom interactive simulators that visualize the object graph, show refs as the simple pointers they are, and animate what checkout, reset, merge, and rebase do to HEAD, the index, and the working directory. You'll see the directed acyclic graph (DAG) take shape, trace reachability through parent chains, and understand why "changing history" means creating entirely new commit objects.
What You'll Build Mental Models For
Git is a content-addressed storage system. Every object is identified by its SHA hash. Identical content produces identical hashes. Objects are immutable: never edited, only created.
Blobs store file content (not filenames). Trees map names to blobs and subtrees. Commits point to a root tree (the snapshot) plus parent commits (the history). These three object types compose everything.
Parent pointers form a directed acyclic graph. Traversing parent chains is how git log works. A commit reachable from a branch tip is safe; an unreachable commit is orphaned. This concept underlies reflog recovery and garbage collection.
Branches and tags are files containing SHA hashes pointing into the object graph. HEAD is a symbolic ref pointing to a branch (attached) or directly to a commit (detached). Branch creation is writing a 40-character file.
checkout moves HEAD, populates the index from the target tree, and updates working files. reset moves the branch pointer: soft stops there, mixed also resets the index, hard also resets working files. Three distinct layers, three modes.
Fast-forward slides a pointer when no divergence exists. Three-way merge finds the merge base, compares both tips, creates a two-parent commit. Rebase creates new commit objects with identical diffs but different parent pointers, making originals unreachable.
Course Curriculum
Visual cheatsheet
Practice verifying AI-generated code
Built for Engineers Who Want Architectural Confidence
This course is for mid-level developers ready to close the gap between "I can use Git" and "I understand what Git is doing." It's for senior engineers who want to mentor others with accurate explanations. It's for technical leaders who need to make decisions about Git workflows with full knowledge of the underlying mechanics.
After this course, you'll predict command behavior before running it. You'll recover from mistakes using reflog because you understand reachability. You'll choose between merge and rebase based on what they actually do to the object graph, not convention.
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