PR #43 was rejected on two findings and had gone unmergeable behind SAFETY-28 and the ALLOC-01 fix. This is the merge commit; the conflict resolution and both fixes are below, because a merge that also changes behaviour has to say so. THE MERGE, AND WHAT IT COST =========================== Two conflicts in main.py, both where SAFETY-28 and this card touched the same method: * `write_setpoint()` split into a site entry point plus a per-unit `_write_unit()` here, while SAFETY-28 put its record gate in the old single-unit body. `write_refusal()` now takes the INVERTER it is about. Asking it with `self.unit` - as release/1.0 does - would authorise A's share on B's wire, and would also trip test_inverter.py part 1's AST scan, which goes red on any read of a Controller N=1 view inside Controller. * the SAFETY-28 gate sits above the clamp and below the non-finite coercion, exactly where release/1.0 put it, and is now asked about `inv`. Fallout the merge produced in the checks, re-aimed rather than relaxed: * every fixture that calls `write_setpoint()` DIRECTLY - the clamp probe, the hung-heartbeat experiment and its serialised counterfactual, the split deadline probe - now arms a real allocation record first. test_inverter.py grows an `arm()` built through the shipped `resolve()`, the same shape test_clamp.py's is: the per-unit envelopes are filed as real `supervised` claims and the site target is their sum, so the water-fill has exactly one answer and the fixture cannot quietly become its own allocator. * test_clamp.py's two-unit failsafe fixture assigned `c.units`, which DEV-02 made a derived property with no setter. It appends a real `Inverter`. BLOCKER 1 - AC 4's ARBITER-BOUND EVIDENCE WAS VACUOUS ===================================================== test_peakguard.py claimed "each unit's `supervised` bound is ITS OWN `max_w` - give inverter B a different rating and the claim filed on inverter B moves with it", and compared B's bound against `_b2.max_w`. `second_inverter()` DEFAULTED B's rating to `LIVE_MAX_W`, which is A's. IT COMPARED (-5000, 5000) AGAINST (-5000, 5000): a number against itself, unable to observe the failure it named. Reproduced: filing the per-unit `device`/`supervised` claims from `self.inverters[0]`'s numbers while leaving `actuator=self.actuator_of(..., inv)` alone left ALL 19 FILES GREEN. At a roster of two with A=5000/B=3000 that makes inverter B's planned envelope (-5000, 5000) instead of (-3000, 3000) - a 2000 W over-command the arbiter believes is supervised. It is a DIFFERENT defect from the actuator variant the static routing pin catches, and only the actuator variant was in the mutation table. * `second_inverter()` gives B 3000 W - a hypothesis, marked as one - for every fixture in the file, so no check there can compare B against A by accident. * the claim is asserted against LITERAL numbers rather than against an expression that can read the same object twice, for `supervised` AND for `device` (whose `dev` had the same defect), plus the envelope the ARBITER RESOLVED for B - a claim filed right and resolved wrong is the same defect one layer down. * a PRECONDITION check fails if the two ratings are ever made equal again. * the BOUND mutation is in the table, beside the actuator one, and was observed RED (3 checks in test_peakguard.py) via tools/mutation_run.sh. ⚠️ THIRD INSTANCE THIS SESSION of a check whose DATA cannot reach the failure it names - ARB-03's call-site scan saw 3 of 8 appends, ALLOC-01's replay generator saw 0 escapes where a widened one saw 39,991. MUTATION.md gains a section for it beside the stale-bytecode and masking ones, and the rule is written at the line: ANY CHECK ASSERTING "X DIFFERS FROM Y" MUST BE RUN ONCE WITH X AND Y ACTUALLY MADE DIFFERENT. BLOCKER 2 - THE LATCH WAS SILENTLY DISARMED BY THE ROLLBACK ROUND TRIP ====================================================================== store.py's rule 2 keeps the flat keys "so a rollback still finds its latch". The operator path that rule contemplates is a ROUND TRIP, and this card lost the latch on it: 1. install migrates -> schema_version=1, unit/inverter-a/... = False 2. operator DOWNGRADES; SAFETY-02 trips inside the downgrade window and the old add-on writes only the flat `sign_tripped: true` 3. operator upgrades again -> `rep.ran` is False, so `_grade_store_migration()` returned early, and `Inverter.__init__` read the namespaced key: False Observed: the controller came up with `sign_wd.tripped = False` while /data/state.json said `sign_tripped: true`. That is store.py's own header sentence - "the file still says sign_tripped: true, the banner is green, and the controller resumes driving the wrong way" - rebuilt by the version marker. A firmware version change with a rollback path was performed on this site on 2026-09-02, so this is not hypothetical. Three changes, each graded by a mutation observed RED: * THE OPERATOR'S CLEAR CLEARS BOTH SPELLINGS. That is what removes the "re-arm forever" objection the `rep.ran` gate existed to answer: with the fossil cleared, `flat True + namespaced False` is unambiguously a downgrade-window latch. * A TRIP MIRRORS THE FLAT PAIR. Rule 2 only ever covered the latch present AT MIGRATION TIME - nothing flat was written for a trip taken afterwards, so an operator who downgraded found `sign_tripped: false` and came up DRIVING. store.py claimed the staleness could only fail toward a SPURIOUS latch. It could not; that sentence is corrected rather than left standing. * THE GUARD RUNS ON EVERY START, and asks the STORE - not the roster - whether anything namespaced is latched. A mirrored trip on B must not re-arm a healthy A, and the store is the right place to ask because it holds every `unit/*/sign_tripped` this install has written, including one belonging to a unit that is not in today's roster. Graded by the three-step scenario itself, run end to end in test_inverter.py part 2, with all three preconditions asserted - including that the catching start did NOT migrate anything, which is what used to skip the guard. Part 2's idempotence check now PRESSES the button instead of hand-writing the store, because the state it used to construct is not one the shipped clear path can produce. Part 3 grades the mirror and the clear on a real roster of two. test_watchdog.py's "the flat key is NOT written" assertion is re-aimed rather than deleted: its argument was right about the READ and wrong about the WRITE. Nothing at runtime reads that key, and the one thing that does ignores it whenever any namespaced latch is set - which a sibling's trip always leaves. What its absence actually cost was the rollback. HANDOVER.md and DOCS.md said the flat key "is never read again", which was the instruction an operator clearing a trip by hand would follow. Both corrected: it is a maintained rollback view, it IS read on every start, and clearing a trip by hand means clearing both spellings. MUTATIONS THIS ROUND, each applied on a purged tree via tools/mutation_run.sh and observed RED: * per-unit `device`/`supervised` BOUNDS from `self.inverters[0]`, actuator left correct -> test_peakguard.py 10g * `_grade_store_migration()` gated on `rep.ran` -> test_inverter.py part 2 * the operator's clear leaving the flat keys set -> test_inverter.py part 2/3 * a trip not mirroring the flat pair -> test_inverter.py part 3 * the guard asking only `self.inverters[0]` -> test_inverter.py part 3 19/19 files green on the merged tree. No hardware was touched. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
GoodWe RS485 Controller — Home Assistant add-on repository
Replaces a GoodWe battery inverter's vendor controller with a local one: holds net grid exchange at zero by emulating the inverter's smart meter over RS485, and runs the monthly battery maintenance cycle the vendor box was doing.
repository.yaml add-on repository metadata
goodwe_controller/ the add-on
config.yaml manifest + options schema (the per-site config form)
app/ the controller
control.py the control law — pure functions, no I/O
maintenance.py the monthly cycle state machine
hass.py Supervisor/Core API access
store.py persistent state in /data
mqtt.py optional status entities
web.py ingress UI
main.py orchestration, heartbeat, failsafe behaviour
test_control.py runnable checks — no framework needed
test_maintenance.py runnable checks — walks a full cycle in fake time
DOCS.md the add-on's documentation tab
MUTATION.md how to run a mutation so the result means something
tools/mutation_run.sh the mutation harness - purges bytecode, then grades
firmware/goodwe-master.yaml ESPHome config for the T-CAN485
estop/rs485_log.py optional RS485 e-stop / bus witness
docs/GoodWe-RS485-Field-Guide.pdf the guide techs carry (10pp, A4)
docs/build_guide.py its single source - rebuilds the HTML and PDF
FIELD-GUIDE.md how to edit and rebuild the guide
Picking this up after a break? Read HANDOVER.md first — current state,
what is known broken, and what to do next.
Install
Settings → Add-ons → Add-on store → ⋮ → Repositories → add
https://gittea.kammenstraatha.duckdns.org/admin/goodwe-addon
then install GoodWe RS485 Controller.
⚠️ The repository must be PUBLIC for this to work. Home Assistant clones it
anonymously; against a private repo the store shows nothing and gives no useful
error. If it must stay private, install locally instead: copy
goodwe_controller/ into the machine's /addons/ folder, then
ha store reload — it appears as a Local add-on.
⚠️ Bump version: in goodwe_controller/config.yaml for every change.
Supervisor keys the built image by that version, so without a bump it silently
reuses the old image and your fix appears not to work — on your bench and on
every client's machine.
Requires Home Assistant OS or Supervised. Add-ons cannot be installed on HA Container or Core.
Read this first
The inverter holds its last command forever. It has no meter-timeout of its own — a controller that dies mid-command leaves the battery running until a human intervenes. Measured on real hardware: 5 kW of discharge held for 113 seconds after a controller went silent.
Three layers exist because of that, and only the third covers the Home Assistant machine itself dying:
- ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
- Wind-down before firmware updates — 0 W written before the update starts.
- RS485 e-stop (optional) — writes 0 W after 30 s of total bus silence.
Sites sold without the e-stop must have the acknowledgement in FIELD-GUIDE.md
§10 signed.
Development
The control law and the maintenance machine are pure Python with no Home Assistant imports, so they run anywhere:
cd goodwe_controller
python3 test_control.py
python3 test_maintenance.py
Both must pass before shipping any change. To prove a check bites - the way
almost every claim in this repository was established - mutate the module and
run tools/mutation_run.sh, which clears __pycache__ first. It is not
optional: a same-size edit reverted inside one second leaves CPython reusing the
old bytecode, and the run grades code that is not there. goodwe_controller/MUTATION.md
has the mechanism, the measurement, and what the flags do not do. They are not unit-test theatre —
each assertion corresponds to a rule whose absence produced an observed failure
on real hardware, and the comments in control.py say which.
Compatibility
Check the serial number, not the model name. Characters 6-8 of the serial are the platform tag:
| tag | platform | verdict |
|---|---|---|
ESU EMU ESA BPS BPU EMJ IJL |
105 — ES/EM/BP, AA55-era meter bus | supported |
SPB SPN |
745 — SBP G2 (GW…-SBP-20) |
no |
ESN ESC |
745 — ES G2 (GW…-ES-20) |
no |
ETU EHU BTU … |
205/745/753 — ET/EH/BT hybrids | no |
SDT DST MSU NSU … |
PV-only inverters — no battery to control | no |
A "-20" or "G2" suffix means a different platform with a different meter
protocol. The tags come from the goodwe library's PLATFORM_105_MODELS, which
is also what Home Assistant's own integration uses to pick a protocol.
- GoodWe ES / BP family inverters (AA55 / RS485 meter-bus generation)
- The protocol is reverse-engineered. There is no vendor contract, and a firmware change on GoodWe's side could break every installation at once. Say so when you sell it.