[NoelStephensUnity]

Purpose of this PR

User-PR: #4181

This PR resolves conditional transitions targeting an Exit node by following transitions through the parent state-machine hierarchy using GetStateMachineTransitions().

This supports both direct and nested Exit transitions, including transitions targeting another state machine. It prevents incorrect validation errors and allows late-joining clients to correctly synchronize the resulting animator state.

Jira ticket

Tracked by GitHub issue #3912.
Fix: #3912.

Changelog

• Fixed: NetworkAnimator now resolves conditional transitions through sub-state-machine Exit nodes.

Documentation

• No documentation changes or additions were necessary.

Testing & QA (How your changes can be verified during release Playtest)

Functional Testing

Manual testing:

• Manual testing done

Verified that a client joining during a State A -> Exit -> State B transition correctly synchronizes with the transition and reaches State B without validation or destination-state errors.

Automated tests:

• Covered by existing automated tests
• Covered by new automated tests

Added EditMode coverage for direct and nested Exit transitions, including transitions targeting another state machine.

Does the change require QA team to:

• Review automated tests?
• Execute manual tests?
• Provide feedback about the PR?

Up-port

Not needed; this PR targets develop-3.x.x.

Backports

#4240

[u-pr]

💡 Harness Review

The change expands transition resolution and adds editor coverage, but the runtime integration still has a late-join synchronization gap.

_{Reviewed commit 96e3a00}

_{🤖 Helpful? 👍/👎}

[NoelStephensUnity]

@u-pr please review again.

[u-pr]

The update in fc9f03227 cleanly addresses the issue of late-joining clients starting in a default state during a non-default transition, and the new NetworkAnimatorLateJoinTransitionTests integration test covers this scenario well.

A few items to consider for this revision:

1. TryGetTransitionInfo fallback to transitions[0]

In TryGetTransitionInfo:

transitionInfo = transitions[0];
foreach (var entry in transitions)
{
    if (entry.OriginatingState == originatingState)
    {
        transitionInfo = entry;
        break;
    }
}
return true;

If the authority is transitioning into destinationState from a state that did not transition via a tracked trigger (e.g., an untracked state, or a transition conditioned on floats/bools/exit time), originatingState will not match any entry in transitions. Because it falls back to transitions[0] and returns true:

• WriteSynchronizationData will set stateHash to transitions[0].OriginatingState and destinationStateHash to destinationState.
• In UpdateAnimationState, because !m_Animator.IsInTransition(...) is now true on late joiners, the client will cross-fade into destinationState using transitions[0]'s duration and starting from transitions[0].OriginatingState, rather than relying on parameter synchronization or direct state playback.

Have you considered returning true only when entry.OriginatingState == originatingState matches, and false otherwise?

2. Defensive null check for childStateMachine.stateMachine

In ParseStateMachineStates:

foreach (var childStateMachine in stateMachine.stateMachines)
{
    var nestedStateMachine = childStateMachine.stateMachine;
    ParseStateMachineStates(layerIndex, ref animatorController, ref nestedStateMachine, childStateMachineParents);
}

If an AnimatorController asset contains a broken or missing sub-state machine reference, childStateMachine.stateMachine can be null, resulting in a NullReferenceException inside ParseStateMachineStates. Adding a null check before recursing guards against this.

3. Redundant ContainsKey(layer) lookups

At lines 1107 and 1571, m_DestinationStateToTransitionInfo.ContainsKey(...) is checked immediately before calling TryGetTransitionInfo(...). Since TryGetTransitionInfo already checks m_DestinationStateToTransitionInfo.TryGetValue(layer, out var layerTransitions), calling TryGetTransitionInfo directly avoids an extra dictionary lookup.

_{🤖 Helpful? 👍/👎}

[NoelStephensUnity]

🤖 All three addressed in 739def1: strict origin match in TryGetTransitionInfo, null check before recursing, and the redundant ContainsKey removed on the authority side (kept on the receiver, where a missing layer table is valid and should not log).

[NoelStephensUnity]

@u-pr please review again

[u-pr]

The latest changes in 739def1 cleanly resolve all previous review items:

• Strict origin state matching: TryGetTransitionInfo now strictly requires entry.OriginatingState == originatingState rather than falling back to transitions[0].
• Defensive null check: Skipping null childStateMachine.stateMachine references prevents potential NullReferenceExceptions when controller assets contain broken sub-state machine links.
• Lookup simplification: Redundant ContainsKey(layer) was removed on the authority side while keeping the check on the receiver to prevent spurious developer error logs on layers without transition tables.
• Test coverage: The negative assertion in TransitionInfoLookupMatchesOriginatingState verifies that unmatched originating states return false, complementing the existing integration and editor tests.

The implementation and accompanying tests look solid and ready to merge.

_{🤖 Helpful? 👍/👎}

[codecov-github-com]

Codecov Report

Attention: Patch coverage is 92.30769% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
....gameobjects/Runtime/Components/NetworkAnimator.cs	92.30%	8 Missing ⚠️

@@                Coverage Diff                @@
##           develop-3.x.x    #4238      +/-   ##
=================================================
+ Coverage          76.90%   77.27%   +0.36%     
=================================================
  Files                159      159              
  Lines              27663    27749      +86     
=================================================
+ Hits               21274    21442     +168     
+ Misses              6389     6307      -82     

Flag	Coverage Δ
NGOv2_project_testproject_ubuntu	76.36% <92.30%> (+0.37%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
....gameobjects/Runtime/Components/NetworkAnimator.cs	85.50% <92.30%> (+9.47%)	⬆️

... and 5 files with indirect coverage changes

Components	Coverage Δ
com.unity.netcode.gameobjects	77.27% <92.38%> (+0.36%)	⬆️

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