fix(calling): don't fail startCall when reaction listener is blocked …

[bluk16]

Summary

From Icm: https://portal.microsofticm.com/imp/v5/incidents/details/21000001115074/summary
startCall (and join) can throw and return a null Call when the app has no involvement with reactions at all, because the stateful client unconditionally registers a 'reaction' listener during call wiring. On calls where that registration is policy-gated by the Calling SDK — notably Teams-identity outbound Group / PSTN calls — the SDK throws an ExpectedError (code=403 subCode=45802 EVENT_SUBSCRIBE_FAIL_POLICY, "Unable to register listener due to meeting policy"). That error propagates out of CallAgent.startCall, aborting call setup even though the application never uses reactions.

This makes reactions — an optional feature — a hard dependency of establishing a call.

Root cause

CallSubscriber's constructor unconditionally constructs a ReactionSubscriber:

this._reactionSubscriber = new ReactionSubscriber(
  this._callIdRef,
  this._context,
  this._call.feature(Features.Reaction)
);

ReactionSubscriber's constructor synchronously calls this._reaction.on('reaction', …). When that .on() is rejected by meeting policy, the exception is thrown during CallSubscriber construction, which happens as part of startCall / join. Nothing catches it, so it surfaces to the caller and the returned Call is null.

Other optional-feature subscribers in this file (captions, real-time text, local recording) are already guarded against exactly this class of failure via the _safeSubscribe helper; the reaction subscriber was missing that guard.

Fix

Wrap the ReactionSubscriber construction in the existing _safeSubscribe(...) helper, which try/catches the subscription and tees any error to state via teeErrorToState instead of letting it abort call setup:

this._safeSubscribe(() => {
  this._reactionSubscriber = new ReactionSubscriber(
    this._callIdRef,
    this._context,
    this._call.feature(Features.Reaction)
  );
});

This mirrors the pattern already used for the other policy-gated optional-feature subscribers, so the behavior is consistent: a blocked reaction subscription no longer breaks a call, and the failure is still observable through latestErrors rather than being swallowed silently.

Testing

• Added a regression test: "should not fail call setup when registering the reaction listener is rejected by meeting policy". It makes the mocked Reaction feature's .on() throw the 403 / EVENT_SUBSCRIBE_FAIL_POLICY error and asserts the call is still set up in state (and the error is tee'd to latestErrors['Call.on']).
• Verified the guard is real: reverting only the _safeSubscribe wrap makes exactly this one test fail; with the fix the full calling-stateful-client suite passes (70/70).

Change type

Bug fix (patch). Change files added for both the stable and beta channels.

[github-actions]

@azure/communication-react jest test coverage for beta.

	Lines	Statements	Functions	Branches
Base	58580 / 95109 61.59%	58580 / 95109 61.59%	1180 / 2709 43.55%	3417 / 5799 58.92%
Current	58631 / 95274 61.53%	58631 / 95274 61.53%	1185 / 2719 43.58%	3408 / 5809 58.66%
Diff	51 / 165 -0.06%	51 / 165 -0.06%	5 / 10 0.03%	-9 / 10 -0.26%

[github-actions]

@azure/communication-react jest test coverage for stable.

	Lines	Statements	Functions	Branches
Base	29739 / 47381 62.76%	29739 / 47381 62.76%	810 / 1491 54.32%	2394 / 3842 62.31%
Current	29732 / 47501 62.59%	29732 / 47501 62.59%	815 / 1501 54.29%	2432 / 3868 62.87%
Diff	-7 / 120 -0.17%	-7 / 120 -0.17%	5 / 10 -0.03%	38 / 26 0.56%

[github-actions]

📦 Chat bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	1793916	1794311	⚠️ increased	395
398.bundle.js	375829	375829	➖ unchanged	0
450.bundle.js	4454	4454	➖ unchanged	0
82.bundle.js	28161	28139	⬇️ decreased	-22
91.bundle.js	4102	4102	➖ unchanged	0

Total change: +373 B ⚠️

[github-actions]

📦 Calling bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	6767681	6769999	⚠️ increased	2318
580.bundle.js	12407925	12407925	➖ unchanged	0

Total change: +2.3 KB ⚠️

[github-actions]

📦 CallWithChat bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	7758336	7760699	⚠️ increased	2363
450.bundle.js	4470	4470	➖ unchanged	0
580.bundle.js	12407938	12407938	➖ unchanged	0
727.bundle.js	372564	372564	➖ unchanged	0
82.bundle.js	28177	28155	⬇️ decreased	-22
91.bundle.js	4118	4118	➖ unchanged	0

Total change: +2.3 KB ⚠️