bug: Public mentors page returns 500 when a mentor has no mentee_section (unguarded NPE)

[yingliu-data]

Bug Report

The public mentors page throws HTTP 500 if any mentor row lacks a mentee_section; the keyword filter has the same unguarded dereference.

• domain/platform/mentorship/Mentor.java:166 — mentor.getMenteeSection().toDto() with no null check.
• utils/FiltersUtil.java:79 — mentor.getMenteeSection().additional() unguarded (while matchesTypes at line 91 explicitly guards null).
• repository/postgres/component/MentorMapper.java:55-56 only sets menteeSection when a row exists, so null is a reachable state (legacy/partial data).

Reproduction

One mentor exists without a mentee_section row → GET /api/cms/v1/mentorship/mentors throws NPE in Mentor.toDto() → unhandled 500 for the entire public mentors page.

Severity

Medium

Potential Risk

• A single malformed mentor record takes down the whole public mentors listing.

Suggested Fix

• Null-guard getMenteeSection() in Mentor.toDto() and in FiltersUtil (mirror the guard already present in matchesTypes).
• Optionally enforce presence of mentee_section at write time so the null state can't arise.
• Add a test rendering a mentor with a null mentee section (expect the list to render, not 500).