fix: DSA sheet progress never persists — accept object completedTopics shape

[vedant7007]

Closes #1727

Problem

saveProgress rejected the real payload with 400:

if (completedTopics !== undefined && !Array.isArray(completedTopics)) { /* 400 "must be an array" */ }

The frontend sends completedTopics as an object/map ({ "0-0-0": true }), and so do the Zod validator (z.record(z.string(), z.boolean())), the Mongoose schema ({ type: Object }), resetProgress ({}), and the import util. !Array.isArray({...}) is true, so every save returned 400 and the frontend .catch swallowed it — progress lived only in localStorage and was lost across devices / on cache clear.

Fix

Validate completedTopics as a plain object (reject arrays/null) to match the rest of the system.

Testing

• node --check on the changed controller.

Contributing as part of Elite Coders Summer of Code (ECSoC 2026).

Summary

• Fixed saveProgress validation for completedTopics.
• The controller now accepts non-null plain objects with boolean values, such as { "0-0-0": true }.
• The controller rejects arrays, null, and non-boolean values.
• Updated the validation error message.
• Verified syntax with node --check.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between e2d6a03 and 200d7c2.

📒 Files selected for processing (1)

• backend/controllers/userSheetProgressController.js

🚧 Files skipped from review as they are similar to previous changes (1)

• backend/controllers/userSheetProgressController.js

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📝 Walkthrough

Walkthrough

The progress controller now validates completedTopics as a non-null object with boolean values. It rejects arrays and invalid value types.

Changes

Progress validation

Layer / File(s)	Summary
Completed topics validation backend/controllers/userSheetProgressController.js	saveProgress accepts boolean-valued object maps for completedTopics, rejects arrays and invalid values, and returns an updated validation error.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• Canopus-Labs/PrepPilot#1565: Modifies progress data handling in userSheetProgressController.js.
• Canopus-Labs/PrepPilot#1619: Modifies concurrent progress saving in saveProgress.
• Canopus-Labs/PrepPilot#1621: Modifies completedTopics validation in the same controller.

Suggested labels: good-backend

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the completedTopics validation fix that restores DSA sheet progress persistence.
Linked Issues check	✅ Passed	The change satisfies issue #1727 by accepting boolean-valued object maps and rejecting arrays, null, and invalid values.
Out of Scope Changes check	✅ Passed	The pull request only changes completedTopics validation in the relevant controller and contains no unrelated changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches 💡 1

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@backend/controllers/userSheetProgressController.js`:
- Around line 63-71: Strengthen the completedTopics validation in the user sheet
progress controller to require a plain object and boolean values for every
property, matching the contract enforced by ValidateUserSheetProgress. Reject
non-plain objects and any entry whose value is not boolean before persisting the
record, while preserving the existing 400 response.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: f3981c68-c780-418a-ac3b-4a331ec7ad11

📥 Commits

Reviewing files that changed from the base of the PR and between a8a7be0 and e2d6a03.

📒 Files selected for processing (1)

• backend/controllers/userSheetProgressController.js

[KaranUnique]

@vedant7007 address the coderabbit suggestions

[vedant7007]

Good catch @coderabbitai — tightened the check to also require every value to be a boolean (Object.values(completedTopics).some(v => typeof v !== 'boolean')), so { "0-0-0": "true" } is now rejected, matching the z.record(z.string(), z.boolean()) contract in ValidateUserSheetProgress.js. (The route runs validateSaveProgress before the controller, so this is a defensive second layer.)

Contributing as part of Elite Coders Summer of Code (ECSoC 2026).

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

@vedant7007 The controller validation now matches the z.record(z.string(), z.boolean()) contract. The defensive check correctly rejects string values such as "true".

🐇 ✓

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✏️ Learnings added

Learnt from: vedant7007
URL: https://github.com/Canopus-Labs/PrepPilot/pull/1729

Timestamp: 2026-08-11T14:34:20.016Z
Learning: In `backend/controllers/userSheetProgressController.js`, `completedTopics` must be a non-null plain object whose values are booleans. This matches the `z.record(z.string(), z.boolean())` contract in `ValidateUserSheetProgress.js`. The `validateSaveProgress` route middleware validates this contract first, and the controller repeats it as a defensive validation layer.

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