refactor(llc): extract the message merge algebra into MessageMerging

[VelikovPetar]

Submit a pull request

Linear: FLU-724

Github Issue: #

CLA

• I have signed the Stream CLA (required).
• The code changes follow best practices
• Code changes are tested (add some information if not applicable)

Important

#2930 and #2942 are merged. Still depends on #2943 — merge that first, after which this PR's diff reduces to the five files below.

Replaces #2913, which could not be rebased: 99% of its channel.dart diff (281 of 282 lines) was inside the block #2930 moved into channel_client_state.dart.

channel_client_state.dart now lives at src/client/channel/. message_merging.dart and message_predicates.dart stay under src/core/util/, since they are channel-agnostic.

Description of the pull request

Moves the pure message/pin/live-location merge and removal operations (formerly private on ChannelClientState) verbatim into a new unexported static holder MessageMerging under lib/src/core/util/, following the MessageRules precedent. The two message predicates (isShownInChannel and hasValidPin, formerly the top-level _pinIsValid and inline filters) live in a separate unexported MessagePredicates extension on Message.

• Call sites in channel_client_state.dart are requalified (16 MessageMerging.* calls, 4 MessagePredicates usages); the stateful orchestrators and persistence writes stay put.
• The thread orchestrators preserve their exact write/no-write emission behavior via an identical() guard.
• Adds pure unit-test suites (41 tests across message_merging_test.dart and message_predicates_test.dart) covering the merge semantics directly, including previously untested pin-expiry filtering and the thread phantom-guard / empty-thread-pruning rules.
• Zero public API change (lib/stream_chat.dart untouched); no CHANGELOG entry since there is no observable behavior change.

ChannelClientState drops from 1,272 to 1,032 lines, and all nine of the private merge/removal helpers are gone.

Test instructions: cd packages/stream_chat && dart test — full package suite passes (1,855 tests), including the existing through-state merge characterization and #2942's event coverage.

Groundwork for the v11 shared merge-semantics rail.

Follow-up worth considering

MessagePredicates is now the natural home for other message predicates that remain inline in the channel state. Not done here to keep the diff a faithful re-derivation.

Screenshots / Videos

No UI changes.

🤖 Generated with Claude Code

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}