addDependency()'s "already exists" check only matched the exact
(ticket_id, depends_on_id, dependency_type) tuple. A user could add
"A blocks B" from ticket A's page, then separately add "B blocked_by
A" from ticket B's page — wouldCreateCycle() correctly found no cycle
(both normalize to the same precedence edge), so the insert was
allowed, creating two DB rows describing one real relationship (shown
twice on ticket B's page: once under Dependencies, once under
Dependents).
Added an inverse-relationship check before the insert: blocks/
blocked_by are inverses of each other, relates_to is its own inverse
(symmetric). duplicates has no defined inverse type in the schema, so
both directions remain independently insertable, which is correct —
"A duplicates B" and "B duplicates A" are distinct claims.
Verified against a local MariaDB instance: the exact repro from the
issue (A blocks B, then B blocked_by A) is now rejected, relates_to's
symmetric case is rejected in both directions, and duplicates in
either direction is unaffected.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MGDKHiU5RJdo3dqQUDow3X