Runtime Debugging Playbook

A playbook for chasing runtime bugs such as empty panels, missing tables, stale seed data, FK failures, blank maps, and frozen-build crashes. Covers symptom→cause→fix for each issue.

Sby Skills Guide Bot
DevelopmentAdvanced
107/27/2026
Claude CodeCursorWindsurfCopilotCodex
#debugging#python#sqlite#frozen-build#troubleshooting

Recommended for


name: debugging description: Use when chasing a runtime bug — empty panels or "no such table", stale seed data after editing data/*.json, FK constraint failures, a blank/white map, dead network features, or frozen-build-only crashes. Symptom→cause→fix playbook plus where the real user DB lives per-OS, how to inspect it, where Qt warnings and JS console output go, and the SSL/resource-path traps specific to this app.

Debugging playbook

Start from the symptom. Each row links to the detail section below.

| Symptom | Most likely cause | Fix | |---|---|---| | Empty panels / sqlite3 ... no such table | DB not initialised, or a bundled data file not found in a frozen build | Reinit DB; confirm resource_path + .spec datas (§1) | | Edited data/*.json but the app shows old data | _SCHEMA_VERSION not bumped → no reseed on existing installs | Bump the version (§2) | | FOREIGN KEY constraint failed | Insert order / stale row vs FKs-on-at-runtime | §3 | | DB seems to be in the "wrong" place, or edits don't take | Looking at the source tree, not the per-user data dir | §4 (per-OS paths) | | Blank / white map area | Web assets not found, or WebEngine can't render | §5 | | No plant photos / no elevation / OSM import empty | Missing CA certs (SSL) or offline with no fallback | §6 | | Works from source, crashes only when installed | Frozen-build resource resolution / missing hidden import | §7 |


1. Empty panels / "no such table"

Two distinct causes:

  • Source checkout: the DB was never seeded. init_db() (src/db/plants.py) is idempotent and runs on first GUI launch and on the first facade call. Force it: python3 -c "from src.db.plants import init_db; init_db()". Then inspect (§4).
  • Frozen build: a bundled data/schema file isn't found. The file must be (a) listed in scripts/packaging/permadesign.spec under datas, and (b) read via src/resources.py resource_path(...), never a __file__-relative join. This exact bug once produced "No such file: schema.sql" on installed builds; tests/test_resource_path.py guards it.

2. Stale seed data after editing data/*.json

init_db() only reseeds when it decides needs_reseed — which is count < 100 or current_version < _SCHEMA_VERSION. So editing seed JSON without bumping _SCHEMA_VERSION (src/db/plants.py, currently 45) means existing installs keep the old rows: the version check is the only trigger that fires the reseed on a populated DB. This is the #1 "my data change didn't show up" cause. See the schema-change and seed-data skills. To force it locally, bump the version, or just delete the user DB (§4) so the next launch reseeds from scratch.

3. FK constraint failures

FK enforcement is ON at runtime (get_connection sets PRAGMA foreign_keys = ON) but temporarily OFF during the bulk reseed. This matters because Python 3.14 enforces FKs at statement time rather than at transaction commit, so seeding a child row before its parent would fail mid-reseed; the reseed path disables FKs for the duration and re-enables after. If you hit a FK error:

  • In normal operation: you're inserting a child (e.g. a plant_uses / plant_fauna row) whose parent id doesn't exist. Insert the parent first, or fix the id.
  • During a reseed you wrote: make sure your new seed step runs inside the FK-off window in init_db, following the existing _seed_* helpers.
  • If you added a dependent table, it must also be added to the reseed wipe list in init_db or it accumulates stale rows across reseeds (see schema-change).

4. Where the real user DB lives (per-OS) + inspecting it

The single source of truth is src/user_paths.py. The per-user data folder is <base>/Site & Pattern/, where <base> is:

| OS | Base | Full DB path | |---|---|---| | Linux | $XDG_DATA_HOME or ~/.local/share | ~/.local/share/Site & Pattern/permadesign.db | | macOS | ~/Library/Application Support | ~/Library/Application Support/Site & Pattern/permadesign.db | | Windows | %APPDATA% | %APPDATA%\Site & Pattern\permadesign.db |

Notes:

  • The filename stays permadesign.db (internal legacy name — deliberate).
  • The folder was PermaDesign before V1.69 and is renamed once, in place, on first launch (user_paths.migrate_legacy_into). If a migration half-happened, you may see both folders; the code no-ops if the target already exists.
  • Never put the DB in the source tree — tests/test_polycultures.py asserts against it.

Inspect it (Linux example):

sqlite3 "$HOME/.local/share/Site & Pattern/permadesign.db" \
  ".tables" "SELECT COUNT(*) FROM plants;" "PRAGMA user_version;"

PRAGMA user_version is where the schema version is stored (_get_schema_version / _set_schema_version); compare it to _SCHEMA_VERSION in src/db/plants.py to see whether a reseed is pending.

Reset to clean state (destroys the user's designs in that DB): delete the permadesign.db file (or the whole Site & Pattern folder) — the next launch recreates and reseeds it. Warn the user first; saved .perma.geojson project files elsewhere are unaffected.

5. Blank / white map

The map is Leaflet inside QWebEngineView (src/map_widget.py), loading html/map.html + the six html/map/*.js files. Causes:

  • Web assets not resolved in a frozen build — same resource_path / .spec datas issue as §1, but for html/.
  • WebEngine can't initialise (missing system libs / sandbox). Run from a terminal (§7) to see the Chromium error.
  • A JS error broke page init. See "seeing JS output" below.

Seeing JS console output / renderer errors: src/map_widget.py routes the embedded page's console.* messages into Python (javaScriptConsoleMessage on the page). Run the app from a terminal and watch stdout/stderr. See the map-frontend skill for the bridge and console routing detail.

6. Network features dead (photos / elevation / OSM / climate)

Offline-first is by design — the app must degrade gracefully — so a dead feature is usually certs, not logic:

  • macOS Pythons and frozen builds ship no root certificates, so every HTTPS fetch fails silently while the Leaflet map (Chromium, own cert store) keeps working. src/ssl_bootstrap.py (ensure_ca_bundle) wires certifi's CA bundle at startup; if it's missing, pip install -r requirements.txt so certifi is present, then rebuild if packaging.
  • Genuinely offline: fetches fall back to DB-cached results and the data/*_fallback_prairie.json regional defaults. See external-data.
  • In this sandbox, outbound HTTPS goes through a proxy — a fetch that hangs is usually waiting on that, not broken code.

7. Frozen build differs from source

  • Run the installed binary from a terminal to see the traceback:
    • Windows: "C:\Program Files\Site & Pattern\SiteAndPattern.exe"
    • macOS: dist/SiteAndPattern.app/Contents/MacOS/SiteAndPattern
    • Linux: ./dist/SiteAndPattern/SiteAndPattern
  • "Missing module": add it to hiddenimports in scripts/packaging/permadesign.spec.
  • Missing data/html: add to datas in the same spec and read via resource_path.
  • See the release-packaging skill and docs/BUILD.md troubleshooting.

Diagnostics quick reference

  • Qt warnings are filtered by a message handler installed in main.py (keeps the console readable); if you're missing an expected Qt warning, that filter is why. Loosen it temporarily while debugging.
  • Typed errors: the facade/domain raise src/errors.py exceptions (ProjectError, AnalysisError, …) rather than popping Qt dialogs — good places to breakpoint.
  • Reproduce headlessly whenever possible via the facade (see agent-api) — it isolates domain bugs from Qt.

Key files

| Path | What | |---|---| | src/user_paths.py | Per-OS data dir + legacy folder migration (source of truth). | | src/db/plants.py | init_db, reseed decision, FK pragma, _SCHEMA_VERSION. | | src/resources.py | resource_path — frozen-build-safe bundled-file resolution. | | src/ssl_bootstrap.py | CA-bundle wiring for headless/frozen HTTPS. | | src/http_utils.py | Shared fetch helpers + timeouts. | | main.py | Qt warning-message filter; app entry. | | src/map_widget.py | Map view; JS console-message routing. | | src/errors.py | Typed exception hierarchy. | | docs/BUILD.md | Troubleshooting section for installed builds. |

Validation

Reproduce the suspected path headlessly, then confirm the fix with the relevant test module (see testing), e.g. after a DB/reseed fix:

python3 -c "from src.db.plants import init_db; init_db(); print('ok')"
python3 -m unittest tests.test_polycultures -v
Related skills