Antipattern: Callback Hell

The smell

• Multiple after_create / after_save / after_commit callbacks doing side effects (charges, emails, jobs, external APIs)
• update_columns used as a workaround to skip them
• Tests must stub or skip callbacks to keep the suite fast
• "Save without notifying" requires hacks

Why it hurts

• Implicit side effects — call sites can't see what happens
• Callback ordering bugs are silent and rare-to-reproduce
• Re-saving for unrelated reasons re-fires effects
• Hard to compose alternative flows (admin imports, backfills)

The fix

• Make side effects explicit at the call site. Replace lifecycle callbacks with named methods controllers/jobs invoke
• Push async work to jobs triggered explicitly, not from after_commit
• Reserve callbacks for invariants tightly coupled to persistence: before_validation normalization, derived columns, dependent: :destroy — things that don't reach outside the row