samples: net: MQTT: transport: Respect Run To Completion

[simensrostad]

Ensure that state changes are executed in order by queueing an event on callbacks from the internal MQTT thread. This ensures correct order and state changes in the state machine.

[NordicBuilder]

CI Information

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Build number: 4

Inputs:

Sources:

sdk-nrf: PR head: 0c3bdec99c83c55c744c2b7e0a6540b12d3c2b26

more details

sdk-nrf:

PR head: 0c3bdec99c83c55c744c2b7e0a6540b12d3c2b26
merge base: 09ee10042bf78d173e63dbd08e80cd05fa0af84a
target head (main): a69dbd907d47e9eb660882e303faffa741afa83f
Diff

Github labels

Enabled	Name	Description
	ci-disabled	Disable the ci execution
	ci-all-test	Run all of ci, no test spec filtering will be done
	ci-force-downstream	Force execution of downstream even if twister fails
	ci-run-twister	Force run twister
	ci-run-zephyr-twister	Force run zephyr twister

List of changed files detected by CI (1)

samples
│  ├── net
│  │  ├── mqtt
│  │  │  ├── src
│  │  │  │  ├── modules
│  │  │  │  │  ├── transport
│  │  │  │  │  │  │ transport.c

Outputs:

Toolchain

Version: 53a57c4d75
Build docker image: docker-dtr.nordicsemi.no/sw-production/ncs-build:53a57c4d75_bba2ea5f2e

Test Spec & Results: ✅ Success; ❌ Failure; 🟠 Queued; 🟡 Progress; ◻️ Skipped; ⚠️ Quarantine

• ◻️ Toolchain - Skipped: existing toolchain is used
• ✅ Build twister
  • sdk-nrf test count: 19
• ✅ Integration tests
  • ✅ test-fw-nrfconnect-nrf-iot_thingy91

Disabled integration tests

• • test-fw-nrfconnect-nrf_lrcs_mosh
  • test-fw-nrfconnect-nrf_lrcs_positioning
  • desktop52_verification
  • doc-internal
  • test_ble_nrf_config
  • test-fw-nrfconnect-apps
  • test-fw-nrfconnect-ble_mesh
  • test-fw-nrfconnect-ble_samples
  • test-fw-nrfconnect-chip
  • test-fw-nrfconnect-fem
  • test-fw-nrfconnect-nfc
  • test-fw-nrfconnect-nrf-iot_libmodem-nrf
  • test-fw-nrfconnect-nrf-iot_lwm2m
  • test-fw-nrfconnect-nrf-iot_samples
  • test-fw-nrfconnect-nrf-iot_serial_lte_modem
  • test-fw-nrfconnect-nrf-iot_zephyr_lwm2m
  • test-fw-nrfconnect-nrf_crypto
  • test-fw-nrfconnect-proprietary_esb
  • test-fw-nrfconnect-rpc
  • test-fw-nrfconnect-rs
  • test-fw-nrfconnect-tfm
  • test-fw-nrfconnect-thread-main
  • test-low-level
  • test-sdk-audio
  • test-sdk-dfu
  • test-sdk-find-my
  • test-sdk-mcuboot
  • test-sdk-pmic-samples
  • test-sdk-wifi
  • test-secdom-samples-public

Note: This message is automatically posted and updated by the CI

[Copilot]

Pull Request Overview

This PR implements a Run To Completion pattern for MQTT transport state management by introducing an event queue mechanism. Instead of directly changing states from MQTT callback threads, state changes are now queued as events and processed in the correct thread context.

Key changes:

• Introduces a private ZBUS channel for internal transport events
• Replaces direct state transitions in MQTT callbacks with event publishing
• Adds event processing logic in the main transport task

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[simensrostad]

@nrfconnect/ncs-modem