Closes#391 (full-replace footgun). Phase 1 of #574 (esp32-csi-node
provisioning UX). The mDNS discovery + USB-CDC pairing work in #574
remains future work; this PR handles only the provision.py-side fix.
Background: provision.py flashed a fresh NVS partition at 0x9000 every
invocation. The previous behaviour built that partition only from the
CLI flags passed on the current run — every key you didn't pass was
silently erased. We hit it ourselves earlier today: --force-partial
only suppressed the safety check but still wiped the SSID.
This PR replaces the full-replace semantic with a per-port state file
that captures every config value previously flashed from this machine.
On each invocation:
1. Read ~/.config/wifi-densepose/esp32-provision-state/<port>.json
(or %APPDATA%/... on Windows).
2. Overlay the new CLI flags on top — CLI wins where set.
3. Generate + flash NVS from the merged dict.
4. Persist the merged dict back to the state file.
Net effect: the exact scenario from #391 + today's incident now
passes (test_partial_invocation_does_not_drop_unrelated_keys):
python provision.py --port COM7 --ssid Net --password p --target-ip 10.0.0.5
# later:
python provision.py --port COM7 --seed-url http://10.0.0.99:8080
# WiFi creds preserved, seed_url added.
New flags:
--reset Wipe per-port state before merging (recycled-board path).
--state-dir Override per-user state dir (XDG / %APPDATA% by default).
--state Print the merged state and exit (debug / inspection).
--force-partial preserved as a deprecation-flagged escape hatch.
State file caveats (in the module docstring): per-machine, atomic
write via .tmp + os.replace, future follow-up to add USB-CDC NVS dump
for device-authoritative merging is tracked in #574.
Tests: tests/test_provision_state.py — 11 tests covering load/save
round-trip, corrupt-JSON resilience, CLI-wins-over-prior, the exact
#391 case, falsy-but-not-None CLI override (node_id=0 must survive),
and serial-port path sanitization for /dev/ttyUSB0. 11/11 pass.
Live-tested end-to-end with --dry-run + --state inspection:
first run: ssid + password + target_ip persisted
second run: --seed-url added — WiFi creds intact in final state.
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