[3/3] Merge sequential exec commands (#2110)

This PR merges and dedupes sequential exec cells so they stack neatly on
sequential lines rather than separate blocks.

This is particularly useful because the model will often sed 200 lines
of a file multiple times in a row and this nicely collapses them.


https://github.com/user-attachments/assets/04cccda5-e2ba-4a97-a613-4547587aa15c

Part 1: https://github.com/openai/codex/pull/2095
Part 2: https://github.com/openai/codex/pull/2097

codex-rs/tui/src/history_cell.rs

@@ -38,6 +38,7 @@ use std::path::PathBuf;
 use std::time::Duration;
 use tracing::error;
 
+#[derive(Clone)]
 pub(crate) struct CommandOutput {
     pub(crate) exit_code: i32,
     pub(crate) stdout: String,
@@ -64,27 +65,37 @@ fn line_to_static(line: &Line) -> Line<'static> {
     }
 }
 
+pub(crate) struct ExecCell {
+    pub(crate) command: Vec<String>,
+    pub(crate) parsed: Vec<ParsedCommand>,
+    pub(crate) output: Option<CommandOutput>,
+}
+
 /// Represents an event to display in the conversation history. Returns its
 /// `Vec<Line<'static>>` representation to make it easier to display in a
 /// scrollable list.
 pub(crate) enum HistoryCell {
     /// Welcome message.
-    WelcomeMessage { view: TextBlock },
-
-    /// Message from the user.
-    UserPrompt { view: TextBlock },
-
-    Exec {
-        command: Vec<String>,
-        parsed: Vec<ParsedCommand>,
-        output: Option<CommandOutput>,
+    WelcomeMessage {
+        view: TextBlock,
     },
 
+    /// Message from the user.
+    UserPrompt {
+        view: TextBlock,
+    },
+
+    Exec(ExecCell),
+
     /// An MCP tool call that has not finished yet.
-    ActiveMcpToolCall { view: TextBlock },
+    ActiveMcpToolCall {
+        view: TextBlock,
+    },
 
     /// Completed MCP tool call where we show the result serialized as JSON.
-    CompletedMcpToolCall { view: TextBlock },
+    CompletedMcpToolCall {
+        view: TextBlock,
+    },
 
     /// Completed MCP tool call where the result is an image.
     /// Admittedly, [mcp_types::CallToolResult] can have multiple content types,
@@ -94,37 +105,57 @@ pub(crate) enum HistoryCell {
     // resized version avoids doing the potentially expensive rescale twice
     // because the scroll-view first calls `height()` for layouting and then
     // `render_window()` for painting.
-    CompletedMcpToolCallWithImageOutput { _image: DynamicImage },
+    CompletedMcpToolCallWithImageOutput {
+        _image: DynamicImage,
+    },
 
     /// Background event.
-    BackgroundEvent { view: TextBlock },
+    BackgroundEvent {
+        view: TextBlock,
+    },
 
     /// Output from the `/diff` command.
-    GitDiffOutput { view: TextBlock },
+    GitDiffOutput {
+        view: TextBlock,
+    },
 
     /// Output from the `/status` command.
-    StatusOutput { view: TextBlock },
+    StatusOutput {
+        view: TextBlock,
+    },
 
     /// Output from the `/prompts` command.
-    PromptsOutput { view: TextBlock },
+    PromptsOutput {
+        view: TextBlock,
+    },
 
     /// Error event from the backend.
-    ErrorEvent { view: TextBlock },
+    ErrorEvent {
+        view: TextBlock,
+    },
 
     /// Info describing the newly-initialized session.
-    SessionInfo { view: TextBlock },
+    SessionInfo {
+        view: TextBlock,
+    },
 
     /// A pending code patch that is awaiting user approval. Mirrors the
     /// behaviour of `ExecCell` so the user sees *what* patch the
     /// model wants to apply before being prompted to approve or deny it.
-    PendingPatch { view: TextBlock },
+    PendingPatch {
+        view: TextBlock,
+    },
 
     /// A human‑friendly rendering of the model's current plan and step
     /// statuses provided via the `update_plan` tool.
-    PlanUpdate { view: TextBlock },
+    PlanUpdate {
+        view: TextBlock,
+    },
 
     /// Result of applying a patch (success or failure) with optional output.
-    PatchApplyResult { view: TextBlock },
+    PatchApplyResult {
+        view: TextBlock,
+    },
 }
 
 const TOOL_CALL_MAX_LINES: usize = 5;
@@ -172,11 +203,11 @@ impl HistoryCell {
             | HistoryCell::ActiveMcpToolCall { view, .. } => {
                 view.lines.iter().map(line_to_static).collect()
             }
-            HistoryCell::Exec {
+            HistoryCell::Exec(ExecCell {
                 command,
                 parsed,
                 output,
-            } => HistoryCell::exec_command_lines(command, parsed, output.as_ref()),
+            }) => HistoryCell::exec_command_lines(command, parsed, output.as_ref()),
             HistoryCell::CompletedMcpToolCallWithImageOutput { .. } => vec![
                 Line::from("tool result (image output omitted)"),
                 Line::from(""),
@@ -279,11 +310,11 @@ impl HistoryCell {
         parsed: Vec<ParsedCommand>,
         output: Option<CommandOutput>,
     ) -> Self {
-        HistoryCell::Exec {
+        HistoryCell::Exec(ExecCell {
             command,
             parsed,
             output,
-        }
+        })
     }
 
     fn exec_command_lines(