fix(terminal): properly cache cursor position for synchronized renders (#3483)

* fix(terminal): properly cache cursor position for synchronized renders

* style(fmt): rustfmt

8 files changed, 109 insertions, 37 deletions

diff --git a/zellij-server/src/panes/grid.rs b/zellij-server/src/panes/grid.rs
index da48422b..c22cb480 100644
--- a/zellij-server/src/panes/grid.rs
+++ b/zellij-server/src/panes/grid.rs
@@ -1142,6 +1142,9 @@ impl Grid {
             Some((self.cursor.x, self.cursor.y))
         }
     }
+    pub fn is_mid_frame(&self) -> bool {
+        self.lock_renders
+    }
     /// Clears all buffers with text for a current screen
     pub fn clear_screen(&mut self) {
         if self.alternate_screen_state.is_some() {
diff --git a/zellij-server/src/panes/terminal_pane.rs b/zellij-server/src/panes/terminal_pane.rs
index 3923b1d9..4df05521 100644
--- a/zellij-server/src/panes/terminal_pane.rs
+++ b/zellij-server/src/panes/terminal_pane.rs
@@ -193,6 +193,9 @@ impl Pane for TerminalPane {
             .cursor_coordinates()
             .map(|(x, y)| (x + left, y + top))
     }
+    fn is_mid_frame(&self) -> bool {
+        self.grid.is_mid_frame()
+    }
     fn adjust_input_to_terminal(
         &mut self,
         key_with_modifier: &Option<KeyWithModifier>,
diff --git a/zellij-server/src/tab/mod.rs b/zellij-server/src/tab/mod.rs
index 3be998cb..92e9eeb9 100644
--- a/zellij-server/src/tab/mod.rs
+++ b/zellij-server/src/tab/mod.rs
@@ -217,6 +217,9 @@ pub trait Pane {
     fn handle_pty_bytes(&mut self, _bytes: VteBytes) {}
     fn handle_plugin_bytes(&mut self, _client_id: ClientId, _bytes: VteBytes) {}
     fn cursor_coordinates(&self) -> Option<(usize, usize)>;
+    fn is_mid_frame(&self) -> bool {
+        false
+    }
     fn adjust_input_to_terminal(
         &mut self,
         _key_with_modifier: &Option<KeyWithModifier>,
@@ -1866,6 +1869,20 @@ impl Tab {
         }
         Ok(should_update_ui)
     }
+    pub fn active_terminal_is_mid_frame(&self, client_id: ClientId) -> Option<bool> {
+        let active_pane_id = if self.floating_panes.panes_are_visible() {
+            self.floating_panes
+                .get_active_pane_id(client_id)
+                .or_else(|| self.tiled_panes.get_active_pane_id(client_id))?
+        } else {
+            self.tiled_panes.get_active_pane_id(client_id)?
+        };
+        let active_terminal = &self
+            .floating_panes
+            .get(&active_pane_id)
+            .or_else(|| self.tiled_panes.get_pane(active_pane_id))?;
+        Some(active_terminal.is_mid_frame())
+    }
     pub fn get_active_terminal_cursor_position(
         &self,
         client_id: ClientId,
@@ -2000,8 +2017,8 @@ impl Tab {
                 .with_context(err_context)?;
         }
 
+        self.render_cursor(output);
         if output.has_rendered_assets() {
-            self.render_cursor(output);
             self.hide_cursor_and_clear_display_as_needed(output);
         }
 
@@ -2044,8 +2061,17 @@ impl Tab {
                                 || previous_shape != &desired_cursor_shape
                         })
                         .unwrap_or(true);
+                    let active_terminal_is_mid_frame = self
+                        .active_terminal_is_mid_frame(client_id)
+                        .unwrap_or(false);
 
-                    if output.is_dirty() || cursor_changed_position_or_shape {
+                    if active_terminal_is_mid_frame {
+                        // no-op, this means the active terminal is currently rendering a frame,
+                        // which means the cursor can be jumping around and we definitely do not
+                        // want to render it
+                        //
+                        // (I felt this was clearer than expanding the if conditional below)
+                    } else if output.is_dirty() || cursor_changed_position_or_shape {
                         let show_cursor = "\u{1b}[?25h";
                         let goto_cursor_position = &format!(
                             "\u{1b}[{};{}H\u{1b}[m{}",
diff --git a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-2.snap b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-2.snap
index e12b6aaa..6e6cd79a 100644
--- a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-2.snap
+++ b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-2.snap
@@ -1,25 +1,25 @@
 ---
 source: zellij-server/src/./unit/screen_tests.rs
-assertion_line: 3501
+assertion_line: 3502
 expression: "format!(\"{}\", snapshot)"
 ---
-00 (C): ┌ Pane #1 ─────────────────────────────────────────────────────────────────────┐
+00 (C): ┌ tiled_pane ──────────────────────────────────────────────────────────────────┐
 01 (C): │                                                                              │
 02 (C): │                                                                              │
 03 (C): │                                                                              │
 04 (C): │                                                                              │
-05 (C): │                                                                              │
-06 (C): │                                                                              │
-07 (C): │                     ┌ file:/path/to/fake/plugin ───────────┐                 │
-08 (C): │                     │Loading file:/path/to/fake/plugin     │                 │
-09 (C): │                     │                                      │                 │
-10 (C): │                     │                                      │                 │
-11 (C): │                     │                                      │                 │
-12 (C): │                     │                                      │                 │
-13 (C): │                     │                                      │                 │
-14 (C): │                     │                                      │                 │
-15 (C): │                     │                                      │                 │
-16 (C): │                     └──────────────────────────────────────┘                 │
+05 (C): │                   ┌ file:/path/to/fake/plugin ───────────┐                   │
+06 (C): │                   │Loading file:/path/to/fake/plugin     │                   │
+07 (C): │                   │                                      │                   │
+08 (C): │                   │                                      │                   │
+09 (C): │                   │                                      │                   │
+10 (C): │                   │                                      │                   │
+11 (C): │                   │                                      │                   │
+12 (C): │                   │                                      │                   │
+13 (C): │                   │                                      │                   │
+14 (C): │                   └──────────────────────────────────────┘                   │
+15 (C): │                                                                              │
+16 (C): │                                                                              │
 17 (C): │                                                                              │
 18 (C): │                                                                              │
 19 (C): └──────────────────────────────────────────────────────────────────────────────┘
diff --git a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-3.snap b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-3.snap
index 652b5726..53ae655c 100644
--- a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-3.snap
+++ b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-3.snap
@@ -1,25 +1,25 @@
 ---
 source: zellij-server/src/./unit/screen_tests.rs
-assertion_line: 3501
+assertion_line: 3502
 expression: "format!(\"{}\", snapshot)"
 ---
-00 (C): ┌ tiled_pane ──────────────────────────────────────────────────────────────────┐
+00 (C): ┌ Pane #1 ─────────────────────────────────────────────────────────────────────┐
 01 (C): │                                                                              │
 02 (C): │                                                                              │
 03 (C): │                                                                              │
 04 (C): │                                                                              │
 05 (C): │                                                                              │
 06 (C): │                                                                              │
-07 (C): │                                                                              │
-08 (C): │                                                                              │
-09 (C): │                                                                              │
-10 (C): │                                                                              │
-11 (C): │                                                                              │
-12 (C): │                                                                              │
-13 (C): │                                                                              │
-14 (C): │                                                                              │
-15 (C): │                                                                              │
-16 (C): │                                                                              │
+07 (C): │                     ┌ file:/path/to/fake/plugin ───────────┐                 │
+08 (C): │                     │Loading file:/path/to/fake/plugin     │                 │
+09 (C): │                     │                                      │                 │
+10 (C): │                     │                                      │                 │
+11 (C): │                     │                                      │                 │
+12 (C): │                     │                                      │                 │
+13 (C): │                     │                                      │                 │
+14 (C): │                     │                                      │                 │
+15 (C): │                     │                                      │                 │
+16 (C): │                     └──────────────────────────────────────┘                 │
 17 (C): │                                                                              │
 18 (C): │                                                                              │
 19 (C): └──────────────────────────────────────────────────────────────────────────────┘
diff --git a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-5.snap b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-5.snap
index 78be0977..8fc16e07 100644
--- a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-5.snap
+++ b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_floating_plugin_pane_to_a_new_tab-5.snap
@@ -1,6 +1,26 @@
 ---
 source: zellij-server/src/./unit/screen_tests.rs
-assertion_line: 3503
-expression: "format!(\"{}\", snapshot_count)"
+assertion_line: 3502
+expression: "format!(\"{}\", snapshot)"
 ---
-4
+00 (C): ┌ tiled_pane ──────────────────────────────────────────────────────────────────┐
+01 (C): │                                                                              │
+02 (C): │                                                                              │
+03 (C): │                                                                              │
+04 (C): │                                                                              │
+05 (C): │                                                                              │
+06 (C): │                                                                              │
+07 (C): │                                                                              │
+08 (C): │                                                                              │
+09 (C): │                                                                              │
+10 (C): │                                                                              │
+11 (C): │                                                                              │
+12 (C): │                                                                              │
+13 (C): │                                                                              │
+14 (C): │                                                                              │
+15 (C): │                                                                              │
+16 (C): │                                                                              │
+17 (C): │                                                                              │
+18 (C): │                                                                              │
+19 (C): └──────────────────────────────────────────────────────────────────────────────┘
+
diff --git a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-4.snap b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-4.snap
index 2681e18e..a55bc4d2 100644
--- a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-4.snap
+++ b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-4.snap
@@ -1,10 +1,10 @@
 ---
 source: zellij-server/src/./unit/screen_tests.rs
-assertion_line: 3428
+assertion_line: 3429
 expression: "format!(\"{}\", snapshot)"
 ---
-00 (C): ┌ pane_to_stay ────────────────────────────────────────────────────────────────┐
-01 (C): │                                                                              │
+00 (C): ┌ plugin_pane_to_break_free ───────────────────────────────────────────────────┐
+01 (C): │Loading file:/path/to/fake/plugin                                             │
 02 (C): │                                                                              │
 03 (C): │                                                                              │
 04 (C): │                                                                              │
diff --git a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-5.snap b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-5.snap
index 5f701fea..91a3ecd4 100644
--- a/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-5.snap
+++ b/zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__screen_can_break_plugin_pane_to_a_new_tab-5.snap
@@ -1,6 +1,26 @@
 ---
 source: zellij-server/src/./unit/screen_tests.rs
-assertion_line: 3430
-expression: "format!(\"{}\", snapshot_count)"
+assertion_line: 3429
+expression: "format!(\"{}\", snapshot)"
 ---
-4
+00 (C): ┌ pane_to_stay ────────────────────────────────────────────────────────────────┐
+01 (C): │                                                                              │
+02 (C): │                                                                              │
+03 (C): │                                                                              │
+04 (C): │                                                                              │
+05 (C): │                                                                              │
+06 (C): │                                                                              │
+07 (C): │                                                                              │
+08 (C): │                                                                              │
+09 (C): │                                                                              │
+10 (C): │                                                                              │
+11 (C): │                                                                              │
+12 (C): │                                                                              │
+13 (C): │                                                                              │
+14 (C): │                                                                              │
+15 (C): │                                                                              │
+16 (C): │                                                                              │
+17 (C): │                                                                              │
+18 (C): │                                                                              │
+19 (C): └──────────────────────────────────────────────────────────────────────────────┘
+