This topic is a practice problem inside the Git Mastery module. The goal is not to memorize the title: reconstruct the problem it solves, the mechanism that makes it work, and the signal that tells you when to use it.
Remember the shape, not the sentence
“Commits are snapshots, branches are pointers, HEAD is just 'you are here'.”
What problem does this solve?
Start from the engineering problem rather than the definition. Rescue lab: recover a 'lost' commit + fix a bad rebase exists because a system needs a reliable way to handle a recurring constraint inside Git Mastery. Ask what would become slow, ambiguous, unsafe, or impossible without it.
How the mechanism works
Break the idea into observable steps. The useful mental model is: input → transformation → decision or state change → output. Keep each step small enough that you can redraw it from memory. The surrounding module is the context: Commits are snapshots, branches are pointers, HEAD is just 'you are here'.
When to reach for it
Use nearby concepts as contrasts. In this module, compare Rescue lab: recover a 'lost' commit + fix a bad rebase with Git internals: blobs, trees, commits — the object graph, Branching strategies: trunk-based vs GitFlow, rebase -i, cherry-pick, reset (soft/mixed/hard). The distinction matters because good engineering choices depend on the constraints, not on memorizing isolated definitions.
See the mechanism before you memorize it
One diagram, one causal story, one reconstruction task.
Rescue lab: recover a 'lost' commit + fix a bad rebase — causal map
Frame
State the problem and the constraints before naming the technique.
Transform
Apply the core mechanism of Rescue lab: recover a 'lost' commit + fix a bad rebase and track what state changes.
Observe
Inspect the artifact, output, invariant, or behavior produced by the mechanism.
Transfer
Explain where the same idea appears elsewhere in DevOps & Git.
Draw the idea yourself
Rebuild the core flow on a real canvas before moving to the worked walkthrough.
Walk the system
Frame
State the problem and the constraints before naming the technique.
Transform
Apply the core mechanism of Rescue lab: recover a 'lost' commit + fix a bad rebase and track what state changes.
Observe
Inspect the artifact, output, invariant, or behavior produced by the mechanism.
Transfer
Explain where the same idea appears elsewhere in DevOps & Git.
Reconstruction card
Use the card as a generative note, not a summary to copy. Fill it from memory after the explanation.
TOPIC: Rescue lab: recover a 'lost' commit + fix a bad rebase
MODULE: Git Mastery
TYPE: practice problem
PROMPT
What problem does it solve?
What changes step by step?
What evidence proves it worked?
When would you choose something else?What usually goes wrong
Close the tab. Rebuild it from memory.
Read the question, answer aloud, then reveal.
What problem is Rescue lab: recover a 'lost' commit + fix a bad rebase designed to solve?Reveal answer
It addresses a recurring constraint inside Git Mastery. A strong answer names the input, the core mechanism, and the result rather than repeating the title.
What are the four stages of the mental model?Reveal answer
Frame the problem → transform the input/state → observe the evidence → transfer the idea to a new scenario.
git reset --hard gone wrong — why is nothing ever lost?Reveal answer
reflog records every HEAD movement for ~90 days; find the pre-reset SHA and reset back to it.
Why never rebase shared/public branches?Reveal answer
Rebase rewrites commit hashes — teammates' clones diverge and every future merge duplicates/conflicts. Rebase local work only.
Make this idea travel.
Connect it next to: Git internals: blobs, trees, commits — the object graph • Branching strategies: trunk-based vs GitFlow • rebase -i, cherry-pick, reset (soft/mixed/hard) • Interactive: disaster recovery with reflog.