Repository navigation
fix(mobile): isolate channel header scroll rebuilds - #9400
Merged
Merged
Conversation
michaelfransen
marked this pull request as ready for review
November 12, 2026 17:24
github-actions
Bot
added
the
codex-security-review-current
🔐 Codex Security Review
Review SummaryOverall Risk: NONE
FindingsNo concrete security, correctness, or reliability findings were identified. Notes
Generated by Codex Security Review | |
kazemek21
approved these changes
Nov 12, 2026
kazemek21
left a comment
kazemek21
left a comment
Contributor
There was a problem hiding this comment.
Kyle reviewed the PR and the Nexus review-tracker notes and approves.
Posted by Codex (gpt-6.1-sol) on behalf of kylez
Keep scroll-driven header animation from rebuilding the channel inventory while preserving provider-driven content updates. Co-authored-by: Karl <9e8471f7b792e46c9c100840959dc71c660786c79c2a3165dbcaf58f52c4266e@buzz.block.builderlab.xyz> Signed-off-by: Michael Fransen <[email protected]>
michaelfransen
force-pushed
the
mfransen/channel-header-rebuilds
branch
from
November 12, 2026 20:45
fd27df6 to
90abe8e
Compare
github-actions
Bot
removed
the
codex-security-review-current
github-actions
Bot
added
the
codex-security-review-current
brow
added a commit
that referenced
this pull request
Nov 12, 2026
## Summary Improve scrolling performance in the Messages channel list by building Solo and Team rows only as needed. Sections currently mount all their rows as one scroll item, which causes long UI stalls with large channel lists. In manual iPhone runs with 500 channels, maximum observed Flutter UI work fell from **65.5 ms to 4.2 ms** after adding lazy rows to a build with header isolation (#9400). The tester reported much smoother scrolling. This was an exploratory comparison with different gestures, not a controlled benchmark of this independent branch. Use stable channel keys and retain section controls, sorting, and collapse animations. Clip the sliver extent during collapse so the animation does not mount the entire section. The shared transition supports downward vertical lists. This is an independent production-only change. Test fixtures and diagnostic instrumentation are excluded; regression checks were run locally and are not included in this PR. ### Related issue Related: #5911 addresses scrolling behavior inside conversations. This change addresses eager row mounting in the Messages channel inventory. No matching open PR or issue was identified in the focused duplicate search. ### Testing On a physical iPhone with 500 channels against an isolated local relay, maximum Flutter UI work fell from 65.5 ms to 4.2 ms after adding lazy rows to a build that already isolated header rebuilds. The tester reported much smoother scrolling. Gestures differed between runs, so this is not a controlled benchmark or an isolated measurement of this branch on its own. The device run preceded the refresh onto current main. Local-only regression journeys passed 12 tests on this independent branch. They cover page laziness and updates, variable-height rows, large text, the last row, collapse reversal, reduced motion, and semantics. These checks are excluded from the commit. Smaller visible jumps remain under investigation; this PR does not claim to resolve them. Generated with Codex --------- Signed-off-by: Michael Fransen <[email protected]> Signed-off-by: Tom Brow <[email protected]> Co-authored-by: Karl <9e8471f7b792e46c9c100840959dc71c660786c79c2a3165dbcaf58f52c4266e@buzz.block.builderlab.xyz> Co-authored-by: Tom Brow <[email protected]> Co-authored-by: Tom Brow <[email protected]> Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz>
brow
approved these changes
Nov 12, 2026
ravarora2
added a commit
that referenced
this pull request
Nov 12, 2026
…small * origin/main: perf(acp): reduce observer CPU and lock overhead (#9381) ci: fix main — stale RunCause call sites and Playwright on ubuntu-26.04 (#9418) fix(mobile): keep shortcut taps and the member picker from wedging (#9388) fix(mobile/ios): close notification code blocks only at line-ending fences (#9349) fix(media): run thumbnail regeneration tests in CI and cap rebuild pixels (#9198) fix(mobile): never show emoji shortcodes in reaction pills (#9411) fix(mobile): isolate channel header scroll rebuilds (#9400) Signed-off-by: Ravneet Arora <[email protected]>
This branch was successfully deployed
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Improve scrolling performance in the Messages channel list by avoiding unnecessary inventory rebuilds as the header moves. Keep scroll-driven header state in a notifier and retain the inventory while the header animates. Provider and parent updates still rebuild the inventory with current channel data.
This complements the lazy-row optimization in #9401. In manual iPhone runs with 500 channels, adding lazy rows on top of header isolation reduced maximum observed Flutter UI work from 65.5 ms to 4.2 ms. That measurement reflects the added lazy-row change; no standalone performance gain was established for header isolation.
This is an independent production-only change. Test fixtures and diagnostic instrumentation are excluded; regression checks were run locally and are not included in this PR.
Related issue
Related: #5911 addresses scrolling behavior inside conversations. This change addresses header-triggered rebuilds in the Messages channel inventory. No matching open PR or issue was identified in the focused duplicate search.
Testing
Exercised Messages on a physical iPhone with 500 channels against an isolated local relay. Header collapse and channel updates worked. This change alone did not remove the large scroll stalls; lazy section rows are a separate change. The device run preceded the refresh onto current main.
Local-only regression checks passed 10 tests on this independent branch. They verify stable inventory identity during header movement and visible channel updates. These checks are excluded from the commit.
Remaining visible jumps are under investigation; this PR does not claim to resolve them.
Generated with Codex