Implement MQTT Message Publishing in MqttManager (CATROID-1673)

[Paras-ydv]

Summary

Extends MqttManager to support publishing MQTT messages to a broker using Eclipse Paho.

This PR previously carried the dependency and settings groundwork (CATROID-1670, CATROID-1672) and the connection lifecycle (CATROID-1671) as extra commits, because none of them were on develop yet. All three have since been merged (#5220, #5222), so the branch has been rebased onto develop and those commits removed. What remains is a single commit containing only the publish work.

CATROID-1673 — Publish implementation

Changes

• Added publish(topic, message) to MqttClientInterface and implemented it in PahoMqttClient
• MqttManager.publish() validates the topic (rejects blank, rejects the # and + wildcards, which are only legal in subscriptions) and the QoS range (0–2)
• Lazy-connects before publishing when no connection is active
• publishFromContext() convenience wrapper for the brick layer
• No forced unwraps; failures are logged and returned as false rather than thrown
• connectionLost now passes the Throwable to Log.e so the stacktrace is kept

Tests

24 new tests covering publish and message building:

• Successful publish, and that the correct topic and payload reach the client
• QoS 0, 1 and 2 accepted; out-of-range QoS rejected
• Retained flag set both ways
• Blank topic rejected, and the client is not called
• Wildcard topics rejected (# and +)
• Lazy connect succeeds before publishing
• No reconnect when a connection already exists
• No publish when the lazy connect fails
• Client exception returns false without crashing
• buildMessage() sets payload, QoS and retained correctly

Two existing tests were updated in this rebase. MqttManager now takes an MqttClientFactory rather than a client instance, following the change made during the CATROID-1671 review, so tests that assumed an injected client had to connect first. Without that, testPublishWhenAlreadyConnectedDoesNotReconnect failed and testSubscribeAfterDisconnectSucceedsAgain did not compile.

Full suite: 4709 tests, 0 failures.

Acceptance criteria

• publish() API added to MqttManager
• publish() added to MqttClientInterface and PahoMqttClient
• Messages published successfully to a connected broker
• Lazy connection established automatically if none exists
• Configurable QoS and retained flag
• Failures logged without crashing
• Unit tests covering the success paths, the validation rejections and the failure modes
• All existing and new tests pass

Your Checklist

• Include the name of the Jira ticket in the PR's title
• Include a summary of the changes plus the relevant context
• Choose the proper base branch (develop)
• Confirm that the changes follow the project's coding guidelines
• Verify that the changes generate no compiler or linter warnings
• Perform a self-review of the changes
• Verify to commit no other files than the intentionally changed ones
• Include reasonable and readable tests verifying the added or changed behavior
• Confirm that new and existing unit tests pass locally
• Check that the commits' message style matches the project's guideline
• Stick to the project's gitflow workflow
• Verify that your changes do not have any conflicts with the base branch
• After the PR, verify that all CI checks have passed
• Post a message in the catroid-stage or catroid-ide Slack channel and ask for a code reviewer

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud