fix(layouts): various kdl layout issues and features (#1797)

* fix(layouts): error on non-bare children node

* refactor(layout): consolidate split direction parsing

* refactor(layout): remove unused import

* fix(layouts): log error when there is no room for layout

* fix(layout): error on size 0

* feat(layouts): allow pane templates to override template command attributes

* style(fmt): rustfmt

9 files changed, 564 insertions, 78 deletions

diff --git a/zellij-utils/src/input/layout.rs b/zellij-utils/src/input/layout.rs
index eea80859f..f823ed401 100644
--- a/zellij-utils/src/input/layout.rs
+++ b/zellij-utils/src/input/layout.rs
@@ -156,8 +156,17 @@ impl PaneLayout {
         }
         count
     }
-    pub fn position_panes_in_space(&self, space: &PaneGeom) -> Vec<(PaneLayout, PaneGeom)> {
-        split_space(space, self, space)
+    pub fn position_panes_in_space(
+        &self,
+        space: &PaneGeom,
+    ) -> Result<Vec<(PaneLayout, PaneGeom)>, &'static str> {
+        let layouts = split_space(space, self, space);
+        for (_pane_layout, pane_geom) in layouts.iter() {
+            if !pane_geom.is_at_least_minimum_size() {
+                return Err("No room on screen for this layout!");
+            }
+        }
+        Ok(layouts)
     }
     pub fn extract_run_instructions(&self) -> Vec<Option<Run>> {
         let mut run_instructions = vec![];
diff --git a/zellij-utils/src/input/unit/layout_test.rs b/zellij-utils/src/input/unit/layout_test.rs
index ffd35f207..ce077a42e 100644
--- a/zellij-utils/src/input/unit/layout_test.rs
+++ b/zellij-utils/src/input/unit/layout_test.rs
@@ -700,7 +700,7 @@ fn children_not_as_first_child_of_pane_template() {
                 }
                 pane
             }
-            horizontal-with-vertical-top name="my tab" {
+            horizontal-with-vertical-top name="my pane" {
                 pane
                 pane
             }
@@ -1014,3 +1014,140 @@ fn error_on_more_than_one_focused_tab() {
     let layout_error = Layout::from_kdl(kdl_layout, "layout_file_name".into()).unwrap_err();
     assert_snapshot!(format!("{:?}", layout_error));
 }
+
+#[test]
+fn args_override_args_in_template() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="tail" {
+                command "tail"
+                args "-f" "/tmp/foo"
+            }
+            tail
+            tail {
+                args "-f" "/tmp/bar"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into()).unwrap();
+    assert_snapshot!(format!("{:#?}", layout));
+}
+
+#[test]
+fn args_added_to_args_in_template() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="tail" {
+                command "tail"
+            }
+            tail
+            tail {
+                args "-f" "/tmp/bar"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into()).unwrap();
+    assert_snapshot!(format!("{:#?}", layout));
+}
+
+#[test]
+fn cwd_override_cwd_in_template() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="tail" {
+                command "tail"
+                cwd "/tmp"
+            }
+            tail
+            tail {
+                cwd "/"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into()).unwrap();
+    assert_snapshot!(format!("{:#?}", layout));
+}
+
+#[test]
+fn cwd_added_to_cwd_in_template() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="tail" {
+                command "tail"
+            }
+            tail
+            tail {
+                cwd "/home"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into()).unwrap();
+    assert_snapshot!(format!("{:#?}", layout));
+}
+
+#[test]
+fn error_on_mixed_command_and_child_panes() {
+    let kdl_layout = r#"
+        layout {
+            pane command="tail" {
+                pane
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into());
+    assert!(layout.is_err(), "error provided");
+}
+
+#[test]
+fn error_on_bare_args_without_command() {
+    let kdl_layout = r#"
+        layout {
+            pane {
+                args "-f"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into());
+    assert!(layout.is_err(), "error provided");
+}
+
+#[test]
+fn error_on_bare_cwd_without_command() {
+    let kdl_layout = r#"
+        layout {
+            pane {
+                cwd "/"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into());
+    assert!(layout.is_err(), "error provided");
+}
+
+#[test]
+fn error_on_bare_cwd_in_template_without_command() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="my_template"
+            my_template {
+                cwd "/"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into());
+    assert!(layout.is_err(), "error provided");
+}
+
+#[test]
+fn error_on_bare_args_in_template_without_command() {
+    let kdl_layout = r#"
+        layout {
+            pane_template name="my_template"
+            my_template {
+                args "--help"
+            }
+        }
+    "#;
+    let layout = Layout::from_kdl(kdl_layout, "layout_file_name".into());
+    assert!(layout.is_err(), "error provided");
+}
diff --git a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_added_to_args_in_template.snap b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_added_to_args_in_template.snap
new file mode 100644
index 000000000..6ff62582d
--- /dev/null
+++ b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_added_to_args_in_template.snap
@@ -0,0 +1,63 @@
+---
+source: zellij-utils/src/input/./unit/layout_test.rs
+assertion_line: 1050
+expression: "format!(\"{:#?}\", layout)"
+---
+Layout {
+    tabs: [],
+    focused_tab_index: None,
+    template: Some(
+        PaneLayout {
+            children_split_direction: Horizontal,
+            name: None,
+            children: [
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [],
+                                cwd: None,
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [
+                                    "-f",
+                                    "/tmp/bar",
+                                ],
+                                cwd: None,
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+            ],
+            split_size: None,
+            run: None,
+            borderless: false,
+            focus: None,
+            external_children_index: None,
+        },
+    ),
+}
diff --git a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_override_args_in_template.snap b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_override_args_in_template.snap
new file mode 100644
index 000000000..4a449d35a
--- /dev/null
+++ b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__args_override_args_in_template.snap
@@ -0,0 +1,66 @@
+---
+source: zellij-utils/src/input/./unit/layout_test.rs
+assertion_line: 1033
+expression: "format!(\"{:#?}\", layout)"
+---
+Layout {
+    tabs: [],
+    focused_tab_index: None,
+    template: Some(
+        PaneLayout {
+            children_split_direction: Horizontal,
+            name: None,
+            children: [
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [
+                                    "-f",
+                                    "/tmp/foo",
+                                ],
+                                cwd: None,
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [
+                                    "-f",
+                                    "/tmp/bar",
+                                ],
+                                cwd: None,
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+            ],
+            split_size: None,
+            run: None,
+            borderless: false,
+            focus: None,
+            external_children_index: None,
+        },
+    ),
+}
diff --git a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__children_not_as_first_child_of_pane_template.snap b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__children_not_as_first_child_of_pane_template.snap
index f82879d2b..f7f904f62 100644
--- a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__children_not_as_first_child_of_pane_template.snap
+++ b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__children_not_as_first_child_of_pane_template.snap
@@ -1,6 +1,6 @@
 ---
 source: zellij-utils/src/input/./unit/layout_test.rs
-assertion_line: 848
+assertion_line: 711
 expression: "format!(\"{:#?}\", layout)"
 ---
 Layout {
@@ -13,7 +13,9 @@ Layout {
             children: [
                 PaneLayout {
                     children_split_direction: Horizontal,
-                    name: None,
+                    name: Some(
+                        "my pane",
+                    ),
                     children: [
                         PaneLayout {
                             children_split_direction: Vertical,
diff --git a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_added_to_cwd_in_template.snap b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_added_to_cwd_in_template.snap
new file mode 100644
index 000000000..3c26fbdd6
--- /dev/null
+++ b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_added_to_cwd_in_template.snap
@@ -0,0 +1,62 @@
+---
+source: zellij-utils/src/input/./unit/layout_test.rs
+assertion_line: 1085
+expression: "format!(\"{:#?}\", layout)"
+---
+Layout {
+    tabs: [],
+    focused_tab_index: None,
+    template: Some(
+        PaneLayout {
+            children_split_direction: Horizontal,
+            name: None,
+            children: [
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [],
+                                cwd: None,
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [],
+                                cwd: Some(
+                                    "/home",
+                                ),
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+            ],
+            split_size: None,
+            run: None,
+            borderless: false,
+            focus: None,
+            external_children_index: None,
+        },
+    ),
+}
diff --git a/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_override_cwd_in_template.snap b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_override_cwd_in_template.snap
new file mode 100644
index 000000000..fd1bc15a1
--- /dev/null
+++ b/zellij-utils/src/input/unit/snapshots/zellij_utils__input__layout__layout_test__cwd_override_cwd_in_template.snap
@@ -0,0 +1,64 @@
+---
+source: zellij-utils/src/input/./unit/layout_test.rs
+assertion_line: 1068
+expression: "format!(\"{:#?}\", layout)"
+---
+Layout {
+    tabs: [],
+    focused_tab_index: None,
+    template: Some(
+        PaneLayout {
+            children_split_direction: Horizontal,
+            name: None,
+            children: [
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [],
+                                cwd: Some(
+                                    "/tmp",
+                                ),
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+                PaneLayout {
+                    children_split_direction: Horizontal,
+                    name: None,
+                    children: [],
+                    split_size: None,
+                    run: Some(
+                        Command(
+                            RunCommand {
+                                command: "tail",
+                                args: [],
+                                cwd: Some(
+                                    "/",
+                                ),
+                                hold_on_close: true,
+                            },
+                        ),
+                    ),
+                    borderless: false,
+                    focus: None,
+                    external_children_index: None,
+                },
+            ],
+            split_size: None,
+            run: None,
+            borderless: false,
+            focus: None,
+            external_children_index: None,
+        },
+    ),
+}
diff --git a/zellij-utils/src/kdl/kdl_layout_parser.rs b/zellij-utils/src/kdl/kdl_layout_parser.rs
index 7261fecbe..6bf2d3724 100644
--- a/zellij-utils/src/kdl/kdl_layout_parser.rs
+++ b/zellij-utils/src/kdl/kdl_layout_parser.rs
@@ -12,7 +12,7 @@ use std::str::FromStr;
 use crate::{
     kdl_child_with_name, kdl_children_nodes, kdl_get_bool_property_or_child_value,
     kdl_get_bool_property_or_child_value_with_error, kdl_get_child,
-    kdl_get_int_property_or_child_value, kdl_get_property_or_child, kdl_get_string_entry,
+    kdl_get_int_property_or_child_value, kdl_get_property_or_child,
     kdl_get_string_property_or_child_value, kdl_get_string_property_or_child_value_with_error,
     kdl_name, kdl_parsing_error, kdl_property_names, kdl_property_or_child_value_node,
     kdl_string_arguments,
@@ -92,8 +92,22 @@ impl<'a> KdlLayoutParser<'a> {
     }
     fn parse_split_size(&self, kdl_node: &KdlNode) -> Result<Option<SplitSize>, ConfigError> {
         if let Some(size) = kdl_get_string_property_or_child_value!(kdl_node, "size") {
-            Ok(Some(SplitSize::from_str(size)?))
+            match SplitSize::from_str(size) {
+                Ok(size) => Ok(Some(size)),
+                Err(_e) => Err(kdl_parsing_error!(
+                    format!(
+                        "size should be a fixed number (eg. 1) or a quoted percent (eg. \"50%\")"
+                    ),
+                    kdl_node
+                )),
+            }
         } else if let Some(size) = kdl_get_int_property_or_child_value!(kdl_node, "size") {
+            if size == 0 {
+                return Err(kdl_parsing_error!(
+                    format!("size should be greater than 0"),
+                    kdl_node
+                ));
+            }
             Ok(Some(SplitSize::Fixed(size as usize)))
         } else if let Some(node) = kdl_property_or_child_value_node!(kdl_node, "size") {
             Err(kdl_parsing_error!(
@@ -143,37 +157,44 @@ impl<'a> KdlLayoutParser<'a> {
             location,
         })))
     }
-    fn parse_pane_command(&self, pane_node: &KdlNode) -> Result<Option<Run>, ConfigError> {
-        let command = kdl_get_string_property_or_child_value_with_error!(pane_node, "command")
-            .map(|c| PathBuf::from(c));
-        let cwd = kdl_get_string_property_or_child_value_with_error!(pane_node, "cwd")
-            .map(|c| PathBuf::from(c));
-        let args = match kdl_get_child!(pane_node, "args") {
+    fn parse_args(&self, pane_node: &KdlNode) -> Result<Option<Vec<String>>, ConfigError> {
+        match kdl_get_child!(pane_node, "args") {
             Some(kdl_args) => {
                 if kdl_args.entries().is_empty() {
                     return Err(kdl_parsing_error!(format!("args cannot be empty and should contain one or more command arguments (eg. args \"-h\" \"-v\")"), kdl_args));
                 }
-                Some(
+                Ok(Some(
                     kdl_string_arguments!(kdl_args)
                         .iter()
                         .map(|s| String::from(*s))
                         .collect(),
-                )
+                ))
             },
-            None => None,
-        };
-        match (command, cwd, args) {
-            (None, Some(_cwd), _) => Err(ConfigError::new_kdl_error(
+            None => Ok(None),
+        }
+    }
+    fn parse_pane_command(
+        &self,
+        pane_node: &KdlNode,
+        is_template: bool,
+    ) -> Result<Option<Run>, ConfigError> {
+        let command = kdl_get_string_property_or_child_value_with_error!(pane_node, "command")
+            .map(|c| PathBuf::from(c));
+        let cwd = kdl_get_string_property_or_child_value_with_error!(pane_node, "cwd")
+            .map(|c| PathBuf::from(c));
+        let args = self.parse_args(pane_node)?;
+        match (command, cwd, args, is_template) {
+            (None, Some(_cwd), _, false) => Err(ConfigError::new_kdl_error(
                 "cwd can only be set if a command was specified".into(),
                 pane_node.span().offset(),
                 pane_node.span().len(),
             )),
-            (None, _, Some(_args)) => Err(ConfigError::new_kdl_error(
+            (None, _, Some(_args), false) => Err(ConfigError::new_kdl_error(
                 "args can only be set if a command was specified".into(),
                 pane_node.span().offset(),
                 pane_node.span().len(),
             )),
-            (Some(command), cwd, args) => Ok(Some(Run::Command(RunCommand {
+            (Some(command), cwd, args, _) => Ok(Some(Run::Command(RunCommand {
                 command,
                 args: args.unwrap_or_else(|| vec![]),
                 cwd,
@@ -186,7 +207,24 @@ impl<'a> KdlLayoutParser<'a> {
         &self,
         kdl_node: &KdlNode,
     ) -> Result<Option<Run>, ConfigError> {
-        let mut run = self.parse_pane_command(kdl_node)?;
+        let mut run = self.parse_pane_command(kdl_node, false)?;
+        if let Some(plugin_block) = kdl_get_child!(kdl_node, "plugin") {
+            if run.is_some() {
+                return Err(ConfigError::new_kdl_error(
+                    "Cannot have both a command and a plugin block for a single pane".into(),
+                    plugin_block.span().offset(),
+                    plugin_block.span().len(),
+                ));
+            }
+            run = self.parse_plugin_block(plugin_block)?;
+        }
+        Ok(run)
+    }
+    fn parse_command_or_plugin_block_for_template(
+        &self,
+        kdl_node: &KdlNode,
+    ) -> Result<Option<Run>, ConfigError> {
+        let mut run = self.parse_pane_command(kdl_node, true)?;
         if let Some(plugin_block) = kdl_get_child!(kdl_node, "plugin") {
             if run.is_some() {
                 return Err(ConfigError::new_kdl_error(
@@ -235,56 +273,90 @@ impl<'a> KdlLayoutParser<'a> {
         let focus = kdl_get_bool_property_or_child_value_with_error!(kdl_node, "focus");
         let name = kdl_get_string_property_or_child_value_with_error!(kdl_node, "name")
             .map(|name| name.to_string());
+        let args = self.parse_args(kdl_node)?;
+        let cwd = kdl_get_string_property_or_child_value_with_error!(kdl_node, "cwd")
+            .map(|c| PathBuf::from(c));
         let split_size = self.parse_split_size(kdl_node)?;
-        let run = self.parse_command_or_plugin_block(kdl_node)?;
+        let run = self.parse_command_or_plugin_block_for_template(kdl_node)?;
+        if let (None, None, true, true) | (None, None, false, true) | (None, None, true, false) =
+            (&run, &pane_layout.run, args.is_some(), cwd.is_some())
+        {
+            let mut offending_nodes = vec![];
+            if args.is_some() {
+                offending_nodes.push("args");
+            }
+            if cwd.is_some() {