Inbound follow records are tied to mutable usernames instead of immutable user IDs

[Ridanshi]

Summary

Inbound follow tracking uses mutable usernames as relationship identifiers.

Username changes can break relationship consistency and historical analytics.

Affected Files

• follow.ts
• analytics.ts
• schema.prisma

Root Cause

Follow relationships reference usernames rather than immutable user identifiers.

When usernames change, historical records become disconnected from the current account identity.

Reproduction

1. Follow a user.
2. Rename the followed account.
3. Inspect inbound follow records.
4. Observe inconsistencies between historical records and current account identity.

Expected Behavior

Follow relationships should remain stable regardless of username changes.

Actual Behavior

Username changes affect relationship consistency.

Why This Is Difficult To Detect

The issue only appears after account renames.

Most follow testing uses static usernames.

Production Impact

• Broken analytics
• Inconsistent relationship tracking
• Historical data corruption
• Identity ambiguity

Suggested Fix

Store immutable user IDs rather than mutable usernames.

Severity

Medium-High

[Ridanshi]

I investigated this issue and would like to work on it.

The current follow tracking implementation appears to rely on mutable usernames rather than immutable user identifiers.

I plan to:

• review follow relationship storage
• migrate relationship logic toward stable identifiers
• preserve existing follow functionality
• add regression tests covering username change scenarios

Please assign this issue to me.