editor: Skip multi-cursor selection broadcast when unshared - #59731
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The per-keystroke `set_active_selections` broadcast does an O(selections) multi-buffer anchor remap and runs even with zero collaborators. Profiling multi-cursor typing showed it costs ~0.9ms/call at 1k cursors and ~8.4ms at 10k, fired ~3x per edited iteration — pure overhead when nobody is observing. - Add `CollaborationHub::should_broadcast_selections`, defaulting to `true`. `Entity<Project>` overrides it to `Project::is_shared()`, which is true for a host that shared the project and for a collab guest, and stays correct before peer-join notifications have propagated locally (unlike a live collaborator count). A purely local project has no audience. - Gate the `set_active_selections` call in `selections_did_change` on it. Follow-mode is unaffected (it uses the separate UpdateFollowers/UpdateView channel); the focused user's own cursors render from `editor.selections`, not `remote_selections`. - input: reuse the post-edit display snapshot in the `hard_wrap` branch instead of taking a redundant fresh buffer snapshot. ~5% faster multi-cursor type+delete at both 1k and 10k cursors (615->583ms at 10k, significant). All 773 editor tests pass.
The previous commit skips the per-keystroke selection broadcast while a project is unshared. On its own that means a peer joining right after the host shares the project would not see the host's cursor until the host next moved it. Re-publish the focused editor's current selections when the project emits RemoteIdChanged(Some), Reshared, or HostReshared, reusing the same focus and leader gating as the per-change broadcast. Addresses review feedback on zed-industries#32051.
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| fn should_broadcast_selections(&self, cx: &App) -> bool { | ||
| let _ = cx; |
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| fn should_broadcast_selections(&self, cx: &App) -> bool { | |
| let _ = cx; | |
| fn should_broadcast_selections(&self, _: &App) -> bool { |
…efault Address review feedback on zed-industries#59731 (osiewicz).
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Follow-up to #58510. Profiling multi-cursor typing on current main showed the per-keystroke
set_active_selectionsbroadcast does an O(selections) multi-buffer anchor remap and runs even with zero collaborators (about 0.9ms/call at 1k cursors, 8.4ms at 10k, fired ~3x per edited iteration).This skips the broadcast when the buffer has no audience, and re-publishes on share so there is no regression:
CollaborationHub::should_broadcast_selections, defaulting totrue.Entity<Project>overrides it toProject::is_shared(), which is true for a host that shared the project and for a collab guest, and stays correct before peer-join notifications have propagated locally (unlike a live collaborator count). A purely local project has no audience.set_active_selectionsinselections_did_changeon it. Follow-mode is unaffected since it uses the separate UpdateFollowers/UpdateView channel, and the focused user's own cursors render fromeditor.selections, notremote_selections.RemoteIdChanged(Some),Reshared,HostReshared), the focused editor re-publishes its current selections, so a peer joining after a share still sees the host's cursor without waiting for the next selection change.hard_wrapbranch instead of taking a redundant fresh buffer snapshot.Multi-cursor type+delete benchmark: about 5% faster at both 1k and 10k cursors (615 to 583 ms at 10k, significant). All 773 editor tests pass locally. Collab and channel-buffer integration tests need the test DB, so they run on CI.
Discussion and profiling: #32051
Release Notes: