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Paths/Backend Engineer/Service Design & Reliability / Production Readiness

Challengeadvancedubuntu:24.04Ask AI

Change the Contract Safely

Old clients and new servers have to coexist for at least one deployment. Write the expand and contract plan that makes that possible.

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01Requirements

live checks
  • File ~/backend/services/compatibility.md exists○
  • The document describes the expand step○
  • The document describes the contract step○
  • The document states the backward compatibility rule○

02Walkthrough

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  1. 01

    Describe the expand step

    Add the new field and keep the old one. Both are valid for as long as old clients exist.

    echo '# Changing a contract safely\n\n## Step 1 - expand\n\nAdd the new field and keep serving the old one. Nothing breaks, because both shapes are valid.' > ~/backend/services/compatibility.md
  2. 3 locked · each failed submit reveals one

03Stuck?

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04AI Tutor

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Tell me what you're stuck on — I'll nudge, not solve. Which requirement are you looking at?

04Notebook

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