chat: PartialEq on ConversationEntry for proper diff

Add PartialEq to Message, FunctionCall, ToolCall, ContentPart,
ImageUrl, MessageContent, ConversationEntry. Sync now compares
entries directly instead of content lengths.

Phase 1 pops mismatched tail entries using PartialEq comparison.
Phase 2 pushes new entries with clone into last_entries buffer.

TODO: route_entry needs to handle multiple tool calls per entry.

Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>

src/agent/api/types.rs

@@ -10,7 +10,7 @@ use chrono::Utc;
 use serde::{Deserialize, Serialize};
 
 /// Function call within a tool call — name + JSON arguments.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct FunctionCall {
     pub name: String,
     pub arguments: String,
@@ -24,7 +24,7 @@ pub struct FunctionCallDelta {
 }
 
 /// A tool call requested by the model.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct ToolCall {
     pub id: String,
     #[serde(rename = "type")]
@@ -45,7 +45,7 @@ pub struct ToolCallDelta {
 /// Message content — either plain text or an array of content parts
 /// (for multimodal messages with images). Serializes as a JSON string
 /// for text-only, or a JSON array for multimodal.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(untagged)]
 pub enum MessageContent {
     Text(String),
@@ -70,7 +70,7 @@ impl MessageContent {
 }
 
 /// A single content part within a multimodal message.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(tag = "type")]
 pub enum ContentPart {
     #[serde(rename = "text")]
@@ -80,13 +80,13 @@ pub enum ContentPart {
 }
 
 /// Image URL — either a real URL or a base64 data URI.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct ImageUrl {
     pub url: String,
 }
 
 /// A chat message in the conversation.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Message {
     pub role: Role,
     pub content: Option<MessageContent>,

src/agent/context.rs

@@ -149,7 +149,7 @@ pub fn is_stream_error(err: &anyhow::Error) -> bool {
 
 /// Conversation entry — either a regular message or memory content.
 /// Memory entries preserve the original message for KV cache round-tripping.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum ConversationEntry {
     Message(Message),
     Memory { key: String, message: Message },

src/user/chat.rs

@@ -25,46 +25,6 @@ enum PaneTarget {
     ToolResult,
 }
 
-/// Route an agent entry to the appropriate pane.
-/// Returns None for entries that shouldn't be displayed (memory, system).
-fn route_entry(entry: &crate::agent::context::ConversationEntry) -> Option<(PaneTarget, String, Marker)> {
-    use crate::agent::api::types::Role;
-    use crate::agent::context::ConversationEntry;
-
-    if let ConversationEntry::Memory { .. } = entry {
-        return None;
-    }
-
-    let msg = entry.message();
-    let text = msg.content_text().to_string();
-
-    match msg.role {
-        Role::User => {
-            if text.starts_with("<system-reminder>") { return None; }
-            Some((PaneTarget::Conversation, text, Marker::User))
-        }
-        Role::Assistant => {
-            // Tool calls → tools pane
-            if let Some(ref calls) = msg.tool_calls {
-                for call in calls {
-                    let line = format!("[{}] {}",
-                        call.function.name,
-                        call.function.arguments.chars().take(80).collect::<String>());
-                    // TODO: return multiple targets — for now just return first tool call
-                    return Some((PaneTarget::Tools, line, Marker::None));
-                }
-            }
-            if text.is_empty() { return None; }
-            Some((PaneTarget::ConversationAssistant, text, Marker::Assistant))
-        }
-        Role::Tool => {
-            if text.is_empty() { return None; }
-            Some((PaneTarget::ToolResult, text, Marker::None))
-        }
-        Role::System => None,
-    }
-}
-
 pub(crate) struct InteractScreen {
     pub(crate) autonomous: PaneState,
     pub(crate) conversation: PaneState,
@@ -80,8 +40,7 @@ pub(crate) struct InteractScreen {
     pub(crate) call_timeout_secs: u64,
     // State sync with agent — double buffer
     last_generation: u64,
-    /// Content lengths of rendered entries — for detecting changes
+    last_entries: Vec<crate::agent::context::ConversationEntry>,
-    last_entry_lengths: Vec<usize>,
     /// Reference to agent for state sync
     agent: std::sync::Arc<tokio::sync::Mutex<crate::agent::Agent>>,
 }
@@ -102,11 +61,47 @@ impl InteractScreen {
             call_started: None,
             call_timeout_secs: 60,
             last_generation: 0,
-            last_entry_lengths: Vec::new(),
+            last_entries: Vec::new(),
             agent,
         }
     }
 
+    /// Route an agent entry to the appropriate pane.
+    /// Returns None for entries that shouldn't be displayed (memory, system).
+    fn route_entry(&mut self, entry: &crate::agent::context::ConversationEntry) -> Option<&mut PaneState> {
+        use crate::agent::api::types::Role;
+        use crate::agent::context::ConversationEntry;
+
+        if let ConversationEntry::Memory { .. } = entry {
+            return None;
+        }
+
+        let msg = entry.message();
+        let text = msg.content_text().to_string();
+
+        match msg.role {
+            if text.is_empty() { return None; }
+            if text.starts_with("<system-reminder>") { return None; }
+
+            Role::User => Some(&mut self.conversation),
+            Role::Assistant => {
+                // Tool calls → tools pane
+                if let Some(ref calls) = msg.tool_calls {
+                    for call in calls {
+                        let line = format!("[{}] {}",
+                            call.function.name,
+                            call.function.arguments.chars().take(80).collect::<String>());
+                        // TODO: return multiple targets — for now just return first tool call
+                        return Some((PaneTarget::Tools, line, Marker::None));
+                    }
+                }
+                Some((PaneTarget::ConversationAssistant, text, Marker::Assistant))
+            }
+            Role::Tool => Some(&mut self.tools),
+            Role::System => None,
+        }
+    }
+
     /// Sync conversation display from agent entries.
     fn sync_from_agent(&mut self) {
         let agent = self.agent.blocking_lock();
@@ -118,34 +113,30 @@ impl InteractScreen {
             self.conversation = PaneState::new(true);
             self.autonomous = PaneState::new(true);
             self.tools = PaneState::new(false);
-            self.last_entry_lengths.clear();
+            self.last_entries.clear();
         } else {
-            // Pop entries from the tail that were removed or changed
+            // Pop entries from the tail that don't match
-            while self.last_entry_lengths.len() > entries.len() {
+            while !self.last_entries.is_empty() {
-                self.last_entry_lengths.pop();
+                let i = self.last_entries.len() - 1;
-                // TODO: pop from correct pane
+                if entries.get(i) == Some(&self.last_entries[i]) {
+                    break;
+                }
+                let popped = self.last_entries.pop().unwrap();
+                if let Some((target, _, _)) = Self::route_entry(&popped) {
+                    match target {
+                        PaneTarget::Conversation | PaneTarget::ConversationAssistant
+                            => self.conversation.pop_line(),
+                        PaneTarget::Tools | PaneTarget::ToolResult
+                            => self.tools.pop_line(),
                     }
-            // Check if last entry changed (streaming)
-            if let (Some(&last_len), Some(entry)) = (
-                self.last_entry_lengths.last(),
-                entries.get(self.last_entry_lengths.len() - 1),
-            ) {
-                let cur_len = entry.message().content_text().len();
-                if cur_len != last_len {
-                    // Last entry changed — pop and re-render
-                    self.last_entry_lengths.pop();
-                    self.conversation.pop_line();
                 }
             }
         }
 
-        // Phase 2: push new/changed entries
+        // Phase 2: push new entries
-        let start = self.last_entry_lengths.len();
+        let start = self.last_entries.len();
         for entry in entries.iter().skip(start) {
-            let msg = entry.message();
+            if let Some((target, text, marker)) = Self::route_entry(entry) {
-            let text_len = msg.content_text().len();
-
-            if let Some((target, text, marker)) = route_entry(entry) {
                 match target {
                     PaneTarget::Conversation => {
                         self.conversation.push_line_with_marker(text, Color::Cyan, marker);
@@ -163,8 +154,7 @@ impl InteractScreen {
                     }
                 }
             }
-
+            self.last_entries.push(entry.clone());
-            self.last_entry_lengths.push(text_len);
         }
 
         self.last_generation = gen;