Avoid constantly scrolling thread history to top as agent generates (#54365)

Max Brunsfeld created 1 week ago

Fixes two problems:

* We were not preserving scroll position in the thread history view when
the thread metadata store updated
* We were updating thread metadata on every single chunk streamed by the
agent, even though the content of the thread does not affect its
metadata.

Release Notes:

- N/A

Change summary

crates/agent_ui/src/conversation_view.rs    |  8 ++++----
crates/agent_ui/src/threads_archive_view.rs | 10 +++-------
2 files changed, 7 insertions(+), 11 deletions(-)

Detailed changes

crates/agent_ui/src/conversation_view.rs

@@ -396,18 +396,18 @@ fn affects_thread_metadata(event: &AcpThreadEvent) -> bool {
     match event {
         AcpThreadEvent::NewEntry
         | AcpThreadEvent::TitleUpdated
-        | AcpThreadEvent::EntryUpdated(_)
-        | AcpThreadEvent::EntriesRemoved(_)
         | AcpThreadEvent::ToolAuthorizationRequested(_)
         | AcpThreadEvent::ToolAuthorizationReceived(_)
-        | AcpThreadEvent::Retry(_)
         | AcpThreadEvent::Stopped(_)
         | AcpThreadEvent::Error
         | AcpThreadEvent::LoadError(_)
         | AcpThreadEvent::Refusal
         | AcpThreadEvent::WorkingDirectoriesUpdated => true,
         // --
-        AcpThreadEvent::TokenUsageUpdated
+        AcpThreadEvent::EntryUpdated(_)
+        | AcpThreadEvent::EntriesRemoved(_)
+        | AcpThreadEvent::Retry(_)
+        | AcpThreadEvent::TokenUsageUpdated
         | AcpThreadEvent::PromptCapabilitiesUpdated
         | AcpThreadEvent::AvailableCommandsUpdated(_)
         | AcpThreadEvent::ModeUpdated(_)

crates/agent_ui/src/threads_archive_view.rs

@@ -320,11 +320,7 @@ impl ThreadsArchiveView {
         let preserve = self.preserve_selection_on_next_update;
         self.preserve_selection_on_next_update = false;
 
-        let saved_scroll = if preserve {
-            Some(self.list_state.logical_scroll_top())
-        } else {
-            None
-        };
+        let saved_scroll = self.list_state.logical_scroll_top();
 
         self.list_state.reset(items.len());
         self.items = items;
@@ -337,9 +333,9 @@ impl ThreadsArchiveView {
             }
         }
 
-        if let Some(scroll_top) = saved_scroll {
-            self.list_state.scroll_to(scroll_top);
+        self.list_state.scroll_to(saved_scroll);
 
+        if preserve {
             if let Some(ix) = self.selection {
                 let next = self.find_next_selectable(ix).or_else(|| {
                     ix.checked_sub(1)