Inner join drops comments from soft-deleted authors Debugging Lab

Inner join drops comments from soft-deleted authorsDatabaseEasyPreparing workspaceAutosaved

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Incident Dossier

Inner join drops comments from soft-deleted authors

Customers report that replies on a blog post vanish whenever the author of a comment deletes their account. The post page is a thread of comments joined against the users table, and rows are quietly dropped from the result.

Initial failing signalMissing rows in joined comments listingExpected 8 comments returned for post 1, with anonymous and soft-deleted authors labelled [deleted] · received Only 6 comments returned; comment ids 103, 105, 106 and 108 are missing

Progress

1Reproduce the bugRun checks

2Edit the fixOpen

3Pass checksOpen

4Submit fixOpen

Reproduction Steps

Run npm test.
Notice that the assertion listing all eight comment ids fails — four rows are missing.
Inspect listCommentsForPost in src/db.js.
Identify which comments survive the join and which disappear, and why.
Make the join preserve every comment row while still rendering soft-deleted and anonymous authors as [deleted].

Focus Mode

Start

src/db.js

Likely area

src/db.js

Progressive hints

Hints reveal broad direction first, then narrow toward the suspect path without showing hidden tests or exact solution code.

TopicDatabase

DifficultyEasy

Est. time15 min

Workspacecreating

Explorer

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Evidence Map

Failing signal loaded from challenge API
Workspace files loaded from workspace API
Results rendered only after API run/submit

Autosaved

workspace

Outputread-onlyready$ workspace boot

Workspace booting...