LibOSPD v4.0 Release Plan

[sidcha]

A lot of things have changed in LibOSDP in preparation for a major release. The following things have to be documented. This issue will track all those topics as a todo list before making the major release.

v4.0 breaking / behavior-changing items

• App-owned queue data(b5823c0) OPT_OSDP_APP_OWNED_QUEUE_DATA is gone — always-on. Apps that submit queued payloads must now register osdp_cp_set_command_completion_callback / osdp_pd_set_event_completion_callback.
• Single channel per OSDP context (04a0851) osdp_cp_setup() / osdp_pd_setup() take a struct osdp_channel * argument. channel removed from osdp_pd_info_t; id removed from struct osdp_channel. Multi-bus deployments must create one osdp_t per channel.
• Retire inline MFGREP support (34cda90) Positive return from pd_command_callback_t for OSDP_CMD_MFG is no longer honored as an inline MFGREP. pd_command_callback_t contract is now 0 = ACK, -ve = NAK, +ve reserved. MFGREP must be emitted asynchronously via osdp_pd_submit_event().
• File-transfer completion is notification-driven (f0990cd) Querying file-transfer status now advances the FSM to idle on terminal states. Callers must consume the new OSDP_EVENT_NOTIFICATION_FILE_TX_DONE (payload enum osdp_file_tx_outcome) to learn the outcome.
• osdp_event_notification renamed to osdp_notification (dfbf978) — the struct is shared by CP events and PD commands, so the event_ prefix was misleading. Source-level rename; enum names unchanged.
• PD-mode notifications now fire the command callback (c07d953) — OSDP_FLAG_ENABLE_NOTIFICATION was previously a PD no-op. It now delivers link / SC transitions via pd_command_callback_t wrapped in osdp_cmd with id OSDP_CMD_NOTIFICATION. PD apps that set the flag must handle or ignore the new command id.
• OSDP_NOTIFICATION_COMMAND.arg1 semantics (c01cc92) Changed from 1 = success, 0 = failure (bool-as-int) to the documented 0 = success, -1 = failure. Consumers comparing against the old values read every success as a failure (caught the pytest suite).
• Adaptive CRC/Checksum handling along with strict capabilities based check-character gating

New features that need explicit documentation or callouts

• Zero-copy RX (772ba9e) OPT_OSDP_RX_ZERO_COPY is a compile-time switch, no fallback. The old buffered osdp_read_fn_t path is removed in zero-copy builds. Python bindings do not support zero-copy builds.
• Static CP builds (19596c9) --static-pd / OPT_OSDP_STATIC_PD renamed to --static / OPT_OSDP_STATIC (old names kept as deprecated aliases). Static builds now include CP, not just PD. Downstream build systems referencing the old preprocessor symbol must update.
• tick_t and its width (c23e05e) Internal timestamps and osdp_millis_now() / osdp_millis_since() switched from int64_t to tick_t. New build flags --bare-metal and --use-32bit-tick-t (requires --bare-metal) let embedded targets opt into a 32-bit tick. Bare-metal apps that override the __weak osdp_millis_now() must change their return type to tick_t.
• Minimal logger mode (e506db6) Opt-in mode where libosdp skips filtering/formatting and hands logs to the app as-is, with a static logger context (lower RAM). Useful for apps that already have a host logging subsystem.