prop/findings.md

Findings — Bugs & Improvements (Non-Critical)

Bugs

🟡 Medium

#	File	Line	Issue	Suggested Fix
1	radio.ex	128, 157	N+1 queries — list_contacts_for_user and list_contacts_involving_callsign don't preload :user	Add `
2	radio.ex	751-757	Missing indexes — dedup query filters on band, qso_timestamp, flagged_invalid with no covering index	Add partial index on (band, qso_timestamp) WHERE flagged_invalid = false
3	grid.ex	31-36	conus_points/0 recomputes ~94k elements on every call — pure function, never memoized	Memoize with module attribute @conus_points conus_points()
4	endpoint.ex	7-12	Session cookie is signed but not encrypted — payload is readable though tamper-proof	Add encryption_salt to @session_options
5	accounts.ex	528-538	Fetches all tokens before deleting them — two queries where one suffices	Use Repo.delete_all(from t in UserToken, where: t.user_id == ^user.id)
6	profiles_file.ex	169-177	Unhandled :zlib.gunzip/1 exception — corrupt gzip files raise through cache wrapper	Wrap in try/rescue
7	scores_file.ex	515	Direct ETS match_delete bypassing Cache API	Use Cache.invalidate or Cache public API
8	profiles_file.ex	323	Same direct ETS access as above	Same fix
9	path_compute.ex	381-394	Six redundant list traversals — 12 passes over 9 profiles for what could be 1 Enum.reduce	Single pass with Enum.reduce
10	hf_muf.ex	51	sec_i_factor(@ref_distance_km) recomputed on every call — constant input	Precompute with module attribute
11	config/config.exs	163	EXLA.Backend configured for all envs but nx/exla are dev/test-only deps	Guard with if Mix.env() in [:dev, :test]

🟢 Low

#	File	Line	Issue	Suggested Fix
12	router.ex	165	Login rate limit 30/min per IP may be generous for brute-force	Consider lowering to 10-15/min
13	application.ex	107-109	Dev/test model loading blocks supervisor start	Wrap in Task.start
14	scorer.ex	126-138	classify_time_period guard boundaries have gap at exactly -3.0	Switch to cond with inclusive/exclusive clarity
15	scorer.ex	636	`
16	path_compute.ex	356-357	Eager Repo.get(Station, ...) instead of preloading assoc	Preload :station upstream
17	radio.ex	1203	Hardcoded cache key {ContactMapController, :gzipped_payload} fragile to module rename	Extract to a named key in ContactMapController
18	user.ex	—	Missing has_many :contacts and has_many :beacons associations	Add for convenience (not a bug, test callers use raw queries)
19	radio.ex	337	Missing partial indexes for enrichment queries	Create filtered indexes on (qso_timestamp) WHERE weather_status IN ('pending','failed')

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Improvements

Architecture & Design

#	Area	Suggestion
1	contact_live_test.exs (3505 lines)	Split into smaller files — currently 2.5x next largest file, uses async: true with shared state, relies on send(lv.pid, ...) / :sys.get_state
2	18 Process.sleep usages in tests	Replace with Process.monitor + assert_receive or :sys.get_state per AGENTS.md
3	25 Process.alive? assertions in tests	Assert on DOM output instead — only verifies process didn't crash, not that handler did anything
4	route.ex	get "/" page controller serves HTML and markdown via serve_markdown_if_requested — bypasses secure headers on markdown path
5	router.ex	Some public routes (/docs/api/openapi.yaml) are inside :browser pipeline but outside live_session — comment explains it's intentional but fragile

Test Coverage Gaps

Module	Status
lib/microwaveprop/ionosphere.ex	Untested
lib/microwaveprop/mailer.ex	Untested
lib/microwaveprop/repo.ex	Untested
lib/microwaveprop/space_weather.ex	Untested
about_live.ex	Real DB query logic, untested

Config & Tooling

#	Finding	Suggested Fix
1	LIVE_VIEW_SIGNING_SALT hardcoded in config.exs, not read from env	Read from System.get_env in runtime.exs
2	:precommit uses deps.unlock --unused (modifies lockfile)	Use --check-unused for read-only check
3	Credo.Check.Warning.UnsafeToAtom disabled	Re-enable to catch String.to_atom(user_input) DOS vector
4	Credo.Check.Readability.Specs disabled	Consider re-enabling for production codebase
5	Credo.Check.Warning.LeakyEnvironment disabled	Re-enable to catch accidental env var logging

Performance Hotspots

#	Area	Impact
1	grid.ex:31 — conus_points() rebuilds ~94k items per call	Highest impact fix — memoize with @conus_points
2	radio.ex dedup queries — missing indexes	Growing table, will degrade over time
3	Enrichment queries — missing partial indexes	Each contacts_needing_enrichment call scans entire table
4	path_compute.ex:381-394 — 12 list traversals for 9-element profile lists	Small today, but unnecessary overhead in hot path

Security (Remaining)

#	Finding	Severity
1	Session cookie missing encryption salt (endpoint.ex:7-12)	Medium
2	String.to_atom/1 not warned by Credo (.credo.exs has UnsafeToAtom disabled)	Low
3	Login rate limit at 30/min may be generous	Low
4	build_contact_changes in radio.ex:1277 uses String.to_existing_atom(key) — safe due to whitelist, but fragile	Low
5	Markdown path bypasses secure browser headers	Low (mitigated by plain-text content type)