agent: surface ACK_FLASH_ERROR instead of returning empty bytes#101
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`FlashAgentClient.read_memory` previously broke its accumulator loop on any RSP_ACK and returned whatever the buffer held — `b""` when the agent rejected the address (e.g. a probe outside the V3+/V4+ I/O whitelist in `agent/main.c:addr_readable`). Callers couldn't tell a successful empty read from a rejection. Same shape in `FlashAgentClient.crc32`, where a clean RSP_ACK rejection was reported as a generic "CRC32 response invalid". Now both inspect the ACK status byte and raise a RuntimeError naming the status, the address, and the size — surfaced while probing eMMC controller MMIO at 0x10100000 on hi3516av300 returned empty bytes silently for ~30s. Also adds the missing `ACK_FLASH_ERROR = 0x02` to the Python protocol constants (already in agent/protocol.h) and updates the existing membw rejection test to use the constant instead of the 0x02 literal. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
FlashAgentClient.read_memory()previously broke its accumulator loop on anyRSP_ACKand returned the buffer as-is. When the agent rejected the address — e.g. a probe outside the V3+/V4+ I/O whitelist inagent/main.c:addr_readable— that meantb\"\"silently. Now it inspects the ACK status byte and raisesRuntimeError(\"Read rejected by agent: status=0x02 …; addr=… size=…\").FlashAgentClient.crc32()had the same shape — a cleanRSP_ACKrejection was reported as a generic "CRC32 response invalid". Now it explicitly detects the ACK and reports the status.ACK_FLASH_ERROR = 0x02tosrc/defib/agent/protocol.py(it already existed inagent/protocol.h). Updates the existing membw rejection test to reference the constant.Context
Surfaced while studying flash on an eMMC-based hi3516av300 over the running agent. The eMMC controller MMIO lives at
0x10100000..0x101FFFFFwhich isn't in the agent's V3+/V4+ whitelist; probing there silently returnedb\"\"for ~30s of wall time across multiple addresses, leading to wasted debugging.Test plan
uv run pytest tests/ -x --ignore=tests/fuzz— 496 passed, 2 skippeduv run ruff check src/defib/agent/ tests/test_agent_protocol.py— cleanuv run mypy src/defib/agent/ --ignore-missing-imports— clean0x10100000now reportsRead rejected by agent: status=0x02 (outside agent's readable whitelist or flash read failed); addr=0x10100000 size=64instead of returning empty bytes.🤖 Generated with Claude Code