fix(serialization): don't serialize when only UI elements present and provide post command discovery hook (#4276)

* do not serialize when only UI elements are present

* start work on a post serialization hook

* add post_command_discovery_hook

* fix tests

* style(fmt): rustfmt

* some cleanups

* moar formatting

* docs(changelog): add PR

CHANGELOG.md

@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * fix: support multiline hyperlinks (https://github.com/zellij-org/zellij/pull/4264)
 * fix: use terminal title when spawning terminal panes from plugin (https://github.com/zellij-org/zellij/pull/4272)
 * fix: allow specifying CWD for tabs without necessitating a layout (https://github.com/zellij-org/zellij/pull/4273)
+* fix: don't serialize when only ui elements present and provide post command disovery hook (https://github.com/zellij-org/zellij/pull/4276)
 
 ## [0.42.2] - 2025-04-15
 * refactor(terminal): track scroll_region as tuple rather than Option (https://github.com/zellij-org/zellij/pull/4082)

zellij-server/src/background_jobs.rs

@@ -237,7 +237,9 @@ pub(crate) fn background_jobs_main(
                                     .unwrap_or(DEFAULT_SERIALIZATION_INTERVAL)
                                     .into()
                             {
-                                let _ = senders.send_to_screen(ScreenInstruction::DumpLayoutToHd);
+                                let _ = senders.send_to_screen(
+                                    ScreenInstruction::SerializeLayoutForResurrection,
+                                );
                                 *last_serialization_time.lock().unwrap() = Instant::now();
                             }
                             task::sleep(std::time::Duration::from_millis(SESSION_READ_DURATION))

zellij-server/src/lib.rs

@@ -414,6 +414,7 @@ impl SessionMetaData {
                 .send_to_pty(PtyInstruction::Reconfigure {
                     client_id,
                     default_editor: new_config.options.scrollback_editor,
+                    post_command_discovery_hook: new_config.options.post_command_discovery_hook,
                 })
                 .unwrap();
         }
@@ -1512,6 +1513,7 @@ fn init_session(
                 ),
                 opts.debug,
                 config_options.scrollback_editor.clone(),
+                config_options.post_command_discovery_hook.clone(),
             );
 
             move || pty_thread_main(pty, layout.clone()).fatal()

zellij-server/src/os_input_output.rs

@@ -512,7 +512,7 @@ pub trait ServerOsApi: Send + Sync {
         HashMap::new()
     }
     /// Get a list of all running commands by their parent process id
-    fn get_all_cmds_by_ppid(&self) -> HashMap<String, Vec<String>> {
+    fn get_all_cmds_by_ppid(&self, _post_hook: &Option<String>) -> HashMap<String, Vec<String>> {
         HashMap::new()
     }
     /// Writes the given buffer to a string
@@ -777,7 +777,7 @@ impl ServerOsApi for ServerOsInputOutput {
 
         cwds
     }
-    fn get_all_cmds_by_ppid(&self) -> HashMap<String, Vec<String>> {
+    fn get_all_cmds_by_ppid(&self, post_hook: &Option<String>) -> HashMap<String, Vec<String>> {
         // the key is the stringified ppid
         let mut cmds = HashMap::new();
         if let Some(output) = Command::new("ps")
@@ -796,7 +796,28 @@ impl ServerOsApi for ServerOsInputOutput {
                 let mut line_parts = line_parts.into_iter();
                 let ppid = line_parts.next();
                 if let Some(ppid) = ppid {
+                    match &post_hook {
+                        Some(post_hook) => {
+                            let command: Vec<String> = line_parts.clone().collect();
+                            let stringified = command.join(" ");
+                            let cmd = match run_command_hook(&stringified, post_hook) {
+                                Ok(command) => command,
+                                Err(e) => {
+                                    log::error!("Post command hook failed to run: {}", e);
+                                    stringified.to_owned()
+                                },
+                            };
+                            let line_parts: Vec<String> = cmd
+                                .trim()
+                                .split_ascii_whitespace()
+                                .map(|p| p.to_owned())
+                                .collect();
+                            cmds.insert(ppid.into(), line_parts);
+                        },
+                        None => {
                             cmds.insert(ppid.into(), line_parts.collect());
+                        },
+                    }
                 }
             }
         }
@@ -930,6 +951,22 @@ pub struct ChildId {
     pub shell: Option<Pid>,
 }
 
+fn run_command_hook(
+    original_command: &str,
+    hook_script: &str,
+) -> Result<String, Box<dyn std::error::Error>> {
+    let output = Command::new("sh")
+        .arg("-c")
+        .arg(hook_script)
+        .env("RESURRECT_COMMAND", original_command)
+        .output()?;
+
+    if !output.status.success() {
+        return Err(format!("Hook failed: {}", String::from_utf8_lossy(&output.stderr)).into());
+    }
+    Ok(String::from_utf8(output.stdout)?.trim().to_string())
+}
+
 #[cfg(test)]
 #[path = "./unit/os_input_output_tests.rs"]
 mod os_input_output_tests;

zellij-server/src/pty.rs

@@ -173,6 +173,7 @@ pub enum PtyInstruction {
     Reconfigure {
         client_id: ClientId,
         default_editor: Option<PathBuf>,
+        post_command_discovery_hook: Option<String>,
     },
     ListClientsToPlugin(SessionLayoutMetadata, PluginId, ClientId),
     Exit,
@@ -211,6 +212,7 @@ pub(crate) struct Pty {
     debug_to_file: bool,
     task_handles: HashMap<u32, JoinHandle<()>>, // terminal_id to join-handle
     default_editor: Option<PathBuf>,
+    post_command_discovery_hook: Option<String>,
 }
 
 pub(crate) fn pty_thread_main(mut pty: Pty, layout: Box<Layout>) -> Result<()> {
@@ -726,9 +728,10 @@ pub(crate) fn pty_thread_main(mut pty: Pty, layout: Box<Layout>) -> Result<()> {
             },
             PtyInstruction::Reconfigure {
                 default_editor,
+                post_command_discovery_hook,
                 client_id: _,
             } => {
-                pty.reconfigure(default_editor);
+                pty.reconfigure(default_editor, post_command_discovery_hook);
             },
             PtyInstruction::Exit => break,
         }
@@ -741,6 +744,7 @@ impl Pty {
         bus: Bus<PtyInstruction>,
         debug_to_file: bool,
         default_editor: Option<PathBuf>,
+        post_command_discovery_hook: Option<String>,
     ) -> Self {
         Pty {
             active_panes: HashMap::new(),
@@ -750,6 +754,7 @@ impl Pty {
             task_handles: HashMap::new(),
             default_editor,
             originating_plugins: HashMap::new(),
+            post_command_discovery_hook,
         }
     }
     pub fn get_default_terminal(
@@ -1430,7 +1435,7 @@ impl Pty {
             .bus
             .os_input
             .as_ref()
-            .map(|os_input| os_input.get_all_cmds_by_ppid())
+            .map(|os_input| os_input.get_all_cmds_by_ppid(&self.post_command_discovery_hook))
             .unwrap_or_default();
 
         for terminal_id in terminal_ids {
@@ -1505,8 +1510,13 @@ impl Pty {
         ))?;
         Ok(())
     }
-    pub fn reconfigure(&mut self, default_editor: Option<PathBuf>) {
+    pub fn reconfigure(
+        &mut self,
+        default_editor: Option<PathBuf>,
+        post_command_discovery_hook: Option<String>,
+    ) {
         self.default_editor = default_editor;
+        self.post_command_discovery_hook = post_command_discovery_hook;
     }
 }
 

zellij-server/src/screen.rs

@@ -353,7 +353,7 @@ pub enum ScreenInstruction {
         bool, // close replaced pane
         ClientTabIndexOrPaneId,
     ),
-    DumpLayoutToHd,
+    SerializeLayoutForResurrection,
     RenameSession(String, ClientId), // String -> new name
     ListClientsMetadata(Option<PathBuf>, ClientId), // Option<PathBuf> - default shell
     Reconfigure {
@@ -595,7 +595,9 @@ impl From<&ScreenInstruction> for ScreenContext {
             ScreenInstruction::UpdateSessionInfos(..) => ScreenContext::UpdateSessionInfos,
             ScreenInstruction::ReplacePane(..) => ScreenContext::ReplacePane,
             ScreenInstruction::NewInPlacePluginPane(..) => ScreenContext::NewInPlacePluginPane,
-            ScreenInstruction::DumpLayoutToHd => ScreenContext::DumpLayoutToHd,
+            ScreenInstruction::SerializeLayoutForResurrection => {
+                ScreenContext::SerializeLayoutForResurrection
+            },
             ScreenInstruction::RenameSession(..) => ScreenContext::RenameSession,
             ScreenInstruction::ListClientsMetadata(..) => ScreenContext::ListClientsMetadata,
             ScreenInstruction::Reconfigure { .. } => ScreenContext::Reconfigure,
@@ -5047,7 +5049,7 @@ pub(crate) fn screen_thread_main(
 
                 screen.render(None)?;
             },
-            ScreenInstruction::DumpLayoutToHd => {
+            ScreenInstruction::SerializeLayoutForResurrection => {
                 if screen.session_serialization {
                     screen.dump_layout_to_hd()?;
                 }

zellij-server/src/session_layout_metadata.rs

@@ -144,15 +144,40 @@ impl SessionLayoutMetadata {
     fn pane_count(&self) -> usize {
         let mut pane_count = 0;
         for tab in &self.tabs {
-            for _tiled_pane in &tab.tiled_panes {
+            for tiled_pane in &tab.tiled_panes {
+                if !self.should_exclude_from_count(tiled_pane) {
                     pane_count += 1;
                 }
-            for _floating_pane in &tab.floating_panes {
+            }
+            for floating_pane in &tab.floating_panes {
+                if !self.should_exclude_from_count(floating_pane) {
                     pane_count += 1;
                 }
             }
+        }
         pane_count
     }
+    fn should_exclude_from_count(&self, pane: &PaneLayoutMetadata) -> bool {
+        if let Some(Run::Plugin(run_plugin)) = &pane.run {
+            let location_string = run_plugin.location_string();
+            if location_string == "zellij:about" {
+                return true;
+            }
+            if location_string == "zellij:session-manager" {
+                return true;
+            }
+            if location_string == "zellij:plugin-manager" {
+                return true;
+            }
+            if location_string == "zellij:configuration-manager" {
+                return true;
+            }
+            if location_string == "zellij:share" {
+                return true;
+            }
+        }
+        false
+    }
     fn is_default_shell(
         default_shell: Option<&PathBuf>,
         command_name: &String,

zellij-utils/assets/config/default.kdl

@@ -506,6 +506,15 @@ load_plugins {
 //
 // advanced_mouse_actions false
 
+// A command to run (will be wrapped with sh -c and provided the RESURRECT_COMMAND env variable)
+// after Zellij attempts to discover a command inside a pane when resurrecting sessions, the STDOUT
+// of this command will be used instead of the discovered RESURRECT_COMMAND
+// can be useful for removing wrappers around commands
+// Note: be sure to escape backslashes and similar characters properly
+//
+// post_command_discovery_hook "echo $RESURRECT_COMMAND | sed <your_regex_here>"
+
+
 web_client {
     font "monospace"
 }

zellij-utils/src/errors.rs

@@ -348,7 +348,7 @@ pub enum ScreenContext {
     UpdateSessionInfos,
     ReplacePane,
     NewInPlacePluginPane,
-    DumpLayoutToHd,
+    SerializeLayoutForResurrection,
     RenameSession,
     DumpLayoutToPlugin,
     ListClientsMetadata,

zellij-utils/src/input/options.rs

@@ -227,6 +227,10 @@ pub struct Options {
     pub web_server_cert: Option<PathBuf>,
     pub web_server_key: Option<PathBuf>,
     pub enforce_https_for_localhost: Option<bool>,
+    /// A command to run after the discovery of running commands when serializing, for the purpose
+    /// of manipulating the command (eg. with a regex) before it gets serialized
+    #[clap(long, value_parser)]
+    pub post_command_discovery_hook: Option<String>,
 }
 
 #[derive(ArgEnum, Deserialize, Serialize, Debug, Clone, Copy, PartialEq)]
@@ -320,6 +324,9 @@ impl Options {
         let enforce_https_for_localhost = other
             .enforce_https_for_localhost
             .or(self.enforce_https_for_localhost);
+        let post_command_discovery_hook = other
+            .post_command_discovery_hook
+            .or(self.post_command_discovery_hook.clone());
 
         Options {
             simplified_ui,
@@ -360,6 +367,7 @@ impl Options {
             web_server_cert,
             web_server_key,
             enforce_https_for_localhost,
+            post_command_discovery_hook,
         }
     }
 
@@ -433,6 +441,9 @@ impl Options {
         let enforce_https_for_localhost = other
             .enforce_https_for_localhost
             .or(self.enforce_https_for_localhost);
+        let post_command_discovery_hook = other
+            .post_command_discovery_hook
+            .or_else(|| self.post_command_discovery_hook.clone());
 
         Options {
             simplified_ui,
@@ -473,6 +484,7 @@ impl Options {
             web_server_cert,
             web_server_key,
             enforce_https_for_localhost,
+            post_command_discovery_hook,
         }
     }
 
@@ -549,6 +561,7 @@ impl From<CliOptions> for Options {
             web_server_cert: opts.web_server_cert,
             web_server_key: opts.web_server_key,
             enforce_https_for_localhost: opts.enforce_https_for_localhost,
+            post_command_discovery_hook: opts.post_command_discovery_hook,
             ..Default::default()
         }
     }

zellij-utils/src/kdl/mod.rs

@@ -2399,6 +2399,9 @@ impl Options {
         let enforce_https_for_localhost =
             kdl_property_first_arg_as_bool_or_error!(kdl_options, "enforce_https_for_localhost")
                 .map(|(v, _)| v);
+        let post_command_discovery_hook =
+            kdl_property_first_arg_as_string_or_error!(kdl_options, "post_command_discovery_hook")
+                .map(|(hook, _entry)| hook.to_string());
 
         Ok(Options {
             simplified_ui,
@@ -2439,6 +2442,7 @@ impl Options {
             web_server_cert,
             web_server_key,
             enforce_https_for_localhost,
+            post_command_discovery_hook,
         })
     }
     pub fn from_string(stringified_keybindings: &String) -> Result<Self, ConfigError> {
@@ -3562,6 +3566,36 @@ impl Options {
             None
         }
     }
+    fn post_command_discovery_hook_to_kdl(&self, add_comments: bool) -> Option<KdlNode> {
+        let comment_text = format!(
+            "{}\n{}\n{}\n{}\n{}\n{}",
+            " ",
+            "// A command to run (will be wrapped with sh -c and provided the RESURRECT_COMMAND env variable) ",
+            "// after Zellij attempts to discover a command inside a pane when resurrecting sessions, the STDOUT",
+            "// of this command will be used instead of the discovered RESURRECT_COMMAND",
+            "// can be useful for removing wrappers around commands",
+            "// Note: be sure to escape backslashes and similar characters properly",
+        );
+
+        let create_node = |node_value: &str| -> KdlNode {
+            let mut node = KdlNode::new("post_command_discovery_hook");
+            node.push(node_value.to_owned());
+            node
+        };
+        if let Some(post_command_discovery_hook) = &self.post_command_discovery_hook {
+            let mut node = create_node(&post_command_discovery_hook);
+            if add_comments {
+                node.set_leading(format!("{}\n", comment_text));
+            }
+            Some(node)
+        } else if add_comments {
+            let mut node = create_node("echo $RESURRECT_COMMAND | sed <your_regex_here>");
+            node.set_leading(format!("{}\n// ", comment_text));
+            Some(node)
+        } else {
+            None
+        }
+    }
     pub fn to_kdl(&self, add_comments: bool) -> Vec<KdlNode> {
         let mut nodes = vec![];
         if let Some(simplified_ui_node) = self.simplified_ui_to_kdl(add_comments) {
@@ -3684,6 +3718,11 @@ impl Options {
         if let Some(web_server_port) = self.web_server_port_to_kdl(add_comments) {
             nodes.push(web_server_port);
         }
+        if let Some(post_command_discovery_hook) =
+            self.post_command_discovery_hook_to_kdl(add_comments)
+        {
+            nodes.push(post_command_discovery_hook);
+        }
         nodes
     }
 }

zellij-utils/src/kdl/snapshots/zellij_utils__kdl__bare_config_from_default_assets_to_string_with_comments.snap

@@ -527,3 +527,10 @@ web_client {
 // Default: 8082
 // (Requires restart)
 // web_server_port 8082
+ 
+// A command to run (will be wrapped with sh -c and provided the RESURRECT_COMMAND env variable) 
+// after Zellij attempts to discover a command inside a pane when resurrecting sessions, the STDOUT
+// of this command will be used instead of the discovered RESURRECT_COMMAND
+// can be useful for removing wrappers around commands
+// Note: be sure to escape backslashes and similar characters properly
+// post_command_discovery_hook "echo $RESURRECT_COMMAND | sed <your_regex_here>"

zellij-utils/src/kdl/snapshots/zellij_utils__kdl__config_options_to_string_with_comments.snap

@@ -254,3 +254,10 @@ web_sharing "disabled"
 // Default: 8082
 // (Requires restart)
 // web_server_port 8082
+ 
+// A command to run (will be wrapped with sh -c and provided the RESURRECT_COMMAND env variable) 
+// after Zellij attempts to discover a command inside a pane when resurrecting sessions, the STDOUT
+// of this command will be used instead of the discovered RESURRECT_COMMAND
+// can be useful for removing wrappers around commands
+// Note: be sure to escape backslashes and similar characters properly
+// post_command_discovery_hook "echo $RESURRECT_COMMAND | sed <your_regex_here>"

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__cli_arguments_override_config_options.snap

@@ -43,4 +43,5 @@ Options {
     web_server_cert: None,
     web_server_key: None,
     enforce_https_for_localhost: None,
+    post_command_discovery_hook: None,
 }

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__cli_arguments_override_layout_options.snap

@@ -43,4 +43,5 @@ Options {
     web_server_cert: None,
     web_server_key: None,
     enforce_https_for_localhost: None,
+    post_command_discovery_hook: None,
 }

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__default_config_with_no_cli_arguments-3.snap

@@ -41,4 +41,5 @@ Options {
     web_server_cert: None,
     web_server_key: None,
     enforce_https_for_localhost: None,
+    post_command_discovery_hook: None,
 }

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__default_config_with_no_cli_arguments.snap

@@ -5969,6 +5969,7 @@ Config {
         web_server_cert: None,
         web_server_key: None,
         enforce_https_for_localhost: None,
+        post_command_discovery_hook: None,
     },
     themes: {},
     plugins: PluginAliases {

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__layout_env_vars_override_config_env_vars.snap

@@ -5969,6 +5969,7 @@ Config {
         web_server_cert: None,
         web_server_key: None,
         enforce_https_for_localhost: None,
+        post_command_discovery_hook: None,
     },
     themes: {},
     plugins: PluginAliases {

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__layout_keybinds_override_config_keybinds.snap

@@ -128,6 +128,7 @@ Config {
         web_server_cert: None,
         web_server_key: None,
         enforce_https_for_localhost: None,
+        post_command_discovery_hook: None,
     },
     themes: {},
     plugins: PluginAliases {

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__layout_options_override_config_options.snap

@@ -43,4 +43,5 @@ Options {
     web_server_cert: None,
     web_server_key: None,
     enforce_https_for_localhost: None,
+    post_command_discovery_hook: None,
 }

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__layout_themes_override_config_themes.snap

@@ -5969,6 +5969,7 @@ Config {
         web_server_cert: None,
         web_server_key: None,
         enforce_https_for_localhost: None,
+        post_command_discovery_hook: None,
     },
     themes: {
         "other-theme-from-config": Theme {

zellij-utils/src/snapshots/zellij_utils__setup__setup_test__layout_ui_config_overrides_config_ui_config.snap

@@ -5969,6 +5969,7 @@ Config {
         web_server_cert: None,
         web_server_key: None,
         enforce_https_for_localhost: None,
+        post_command_discovery_hook: None,
     },
     themes: {},
     plugins: PluginAliases {