fbuild-python DaemonConnection drops PLATFORMIO_SRC_DIR so FastLED autoresearch builds the wrong sketch

[zackees]

Tracked from FastLED/FastLED#2510.

Symptom

On the ESP32-P4-EV autoresearch path, FastLED sets PLATFORMIO_SRC_DIR=examples/AutoResearch before calling into fbuild-python via connect_daemon(...).deploy(...). The daemon build/deploy request sent by the Python binding does not include src_dir, so the daemon falls back to platformio.ini's default src_dir = examples/Sailboat and autoresearch fails before it can flash/run the AutoResearch firmware.

Observed locally from C:/Users/niteris/dev/fastled7:

bash autoresearch esp32p4 --parlio --skip-lint --timeout 120
...
[fbuild] operation failed: build error: build failed: compilation failed for
C:\Users\niteris\dev\fastled7\.fbuild\build\esp32p4\release\src\Sailboat.ino.cpp:
.fbuild/build/esp32p4/release/src/Sailboat.ino.cpp:1:10: fatal error: Arduino.h: No such file or directory

The fbuild CLI path does work when the same env var is forwarded:

$env:PLATFORMIO_SRC_DIR=(Resolve-Path examples\AutoResearch).Path
.\.venv\Scripts\fbuild.exe . build -e esp32p4 -v

That produces AutoResearch.ino_*, AutoResearchRemote_*, etc. under .fbuild/build/esp32p4/release/src/, confirming that the daemon/build side can honor src_dir when it receives it.

Root cause

The Rust CLI forwards PLATFORMIO_SRC_DIR into BuildRequest/DeployRequest.src_dir, but the PyO3 DaemonConnection/AsyncDaemonConnection request model omits src_dir entirely. FastLED's autoresearch wrapper uses the Python binding path, so the caller env override is lost.

Expected fix

Forward the caller's PLATFORMIO_SRC_DIR through fbuild-python build/deploy requests, preferably by adding src_dir to the shared OpRequest and populating it from std::env::var(PLATFORMIO_SRC_DIR) when non-empty. Keep existing Python signatures backwards compatible.

Done

• DaemonConnection.deploy() and AsyncDaemonConnection.deploy() include src_dir when PLATFORMIO_SRC_DIR is set.
• Build requests do the same for parity with the CLI.
• Unit tests cover forwarding and empty-env omission.
• agent runbook: get bash autoresearch esp32p4 --parlio working end-to-end on the attached EV board FastLED#2510 can get past the wrong-sketch build blocker.