[ECO-5117] Fix channel ATTACH/DETACH state checks

[sacOO7]

Fixed #1045

Summary by CodeRabbit

• New Features

  • Enhanced channel state management during attachment and detachment operations.
  • Improved handling for channel states such as failed and suspended.

• Bug Fixes

  • Resolved issues related to publishing messages when the channel is in a failed or suspended state.

• Tests

  • Added new test cases to validate channel behavior in various states, ensuring robust testing of attachment and detachment functionalities.

[coderabbitai]

Walkthrough

The changes in this pull request involve modifications to the ChannelBase class and its associated test suite, RealtimeChannelTest. The primary focus is on improving the handling of channel states during attach and detach operations, specifically addressing the failed and suspended states. The attachImpl and detachImpl methods have been updated for better state management, and new unit tests have been added to validate these behaviors.

Changes

File	Change Summary
lib/src/main/java/io/ably/lib/realtime/ChannelBase.java	- Enhanced state handling in attachImpl and detachImpl methods for failed and suspended states. - Updated setState method for state transitions. - Modified publish methods to check channel states.
lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java	- Added new tests for channel attachment and detachment in failed and suspended states. - Refined assertions in existing tests for clarity.

Assessment against linked issues

Objective	Addressed	Explanation
Implement handling for suspended and failed states during attach/detach (1045, ECO-5117)	✅
Add unit tests for channel state management during attach/detach (1045, ECO-5117)	✅

Possibly related PRs

• Fix implicit attach on subscribe #1028: This PR modifies the ChannelBase class to enhance subscription functionality, which is closely related to the changes in the main PR that also focus on channel state management during attachment and detachment.
• [ECO-4972] Fix implicit channel ATTACH #1043: This PR addresses issues related to channel attachment and subscription, including updates to the RealtimeChannelTest class that enhance testing for channel states, aligning with the main PR's focus on state management in the ChannelBase class.

Suggested reviewers

• ttypic

Poem

In the channels where we play,
States now dance in a new way.
Failed or suspended, fear not,
Attach and detach, give it a shot!
With tests to guard our joyful spree,
Robust and clear, we hop with glee! 🐇✨

---

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[coderabbitai]

Actionable comments posted: 3

🧹 Outside diff range and nitpick comments (1)

lib/src/main/java/io/ably/lib/realtime/ChannelBase.java (1)

Line range hint 948-950: Address the TODO comment regarding test failure in setConnected

The setConnected method contains a TODO comment indicating a failing test due to explicit attach after connect. Investigate and resolve this issue to ensure that the channel correctly reattaches when the connection is reestablished, adhering to RTN15c6 and RTN15c7 specifications.

Would you like assistance in diagnosing the test failure or updating the test to reflect the intended behavior?

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between dc4d464 and ec5b6dd.

📒 Files selected for processing (2)

• lib/src/main/java/io/ably/lib/realtime/ChannelBase.java (2 hunks)
• lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java (3 hunks)

🔇 Additional comments (5)

lib/src/main/java/io/ably/lib/realtime/ChannelBase.java (5)

224-236: Verify handling of 'failed' state during attach

In the attachImpl method, when the channel state is failed, the code sets this.reason = null; and proceeds without explicitly initiating a new attach operation. Ensure that this approach aligns with the RTL4g specification, which states that the channel should proceed as if it were in the initialized state when attach is called on a failed channel.

---

317-322: Confirm success callback for 'initialized' and 'detached' states in detach

In the detachImpl method, when the channel state is initialized or detached, the code calls callCompletionListenerSuccess(listener);. Verify that returning success in these states is appropriate and consistent with the RTL5a specification.

---

322-330: Handle pending detach requests in 'detaching' and 'attaching' states

The code adds the listener to the channel's state change listeners when the state is detaching, and queues the detach request when the state is attaching. Ensure that this logic correctly handles concurrent detach operations as specified in RTL5i.

---

330-334: Appropriate error callback for 'failed' state during detach

In the detachImpl method, when the channel state is failed, the code constructs an ErrorInfo object based on this.reason and calls callCompletionListenerError(listener, error);. This behavior aligns with the RTL5b specification, which expects an error when detaching a channel in a failed state.

---

335-338: Transition from 'suspended' to 'detached' during detach

When the channel state is suspended, the code transitions the state to detached by calling setState(ChannelState.detached, null); and then invokes callCompletionListenerSuccess(listener);. This complies with the RTL5j specification, ensuring proper state management during detach operations from a suspended state.

[ttypic]

LGTM

[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (2)

lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java (2)

1071-1106: Good test coverage for detach in suspended state.

The test effectively verifies channel detach behavior when in suspended state. Consider adding a verification that channel.reason is null after successful detach, similar to the attach test.

 /* Verify onSuccess callback gets called */
 detachWaiter.waitFor();
 assertTrue(detachWaiter.success);
+assertNull("Verify error reason is cleared", channel.reason);

---

1108-1147: Comprehensive test for detach failure in failed state.

Good validation of error conditions and state transitions. Consider adding a test case for the scenario where the channel moves from failed to attached state while a detach operation is pending.

@Test
public void detach_pending_when_channel_moves_to_attached() {
    // Setup code...
    
    // Simulate connection failure
    ably.connection.connectionManager.requestState(ConnectionState.failed);
    channelWaiter.waitFor(ChannelState.failed);
    
    // Start detach operation
    Helpers.CompletionWaiter detachWaiter = new Helpers.CompletionWaiter();
    channel.detach(detachWaiter);
    
    // Move channel to attached state
    ably.connection.connectionManager.requestState(ConnectionState.connected);
    channelWaiter.waitFor(ChannelState.attached);
    
    // Verify detach operation completes successfully
    detachWaiter.waitFor();
    assertTrue(detachWaiter.success);
}

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between ec5b6dd and 47cd42f.

📒 Files selected for processing (1)

• lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java (3 hunks)

🔇 Additional comments (2)

lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java (2)

933-933: LGTM! Improved assertion message clarity.

The updated assertion message better describes the expected state.

---

947-998: Well structured test for channel attach in failed state.

Good test coverage that:

1. Properly simulates connection failure
2. Verifies state transitions (attached -> failed -> attaching -> attached)
3. Validates error information
4. Checks cleanup of error reason after reattach

[sacOO7]

@coderabbitai resolve

[coderabbitai]

✅ Actions performed

Comments resolved.