Rework `--class` CLI option

This commit swaps the order of `general` and `instance` arguments
and also sets `instance` to `general` when only one argument was
provided. This should make this option behave like in other terminals
on X11, since they set either both or general by default, but
not instance like Alacritty.

Fixes #6279.

4 files changed, 27 insertions, 20 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff19cc77..85364b8e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,6 +40,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Warn when either `columns` or `lines` is non-zero, but not both
 - Client side decorations should have proper text rendering now on Wayland
 - Config option `window.gtk_theme_variant`, you should use `window.decorations_theme_variant` instead
+- `--class` now sets both class part of WM_CLASS property and instance
+- `--class`'s `general` and `instance` options were swapped
 
 ### Fixed
 
diff --git a/alacritty/src/cli.rs b/alacritty/src/cli.rs
index 8872ec99..e9c563d4 100644
--- a/alacritty/src/cli.rs
+++ b/alacritty/src/cli.rs
@@ -11,7 +11,7 @@ use serde_yaml::Value;
 
 use alacritty_terminal::config::{Program, PtyConfig};
 
-use crate::config::window::{Class, Identity, DEFAULT_NAME};
+use crate::config::window::{Class, Identity};
 use crate::config::{serde_utils, UiConfig};
 
 /// CLI options for the main Alacritty executable.
@@ -159,19 +159,16 @@ fn option_as_value(option: &str) -> Result<Value, serde_yaml::Error> {
 
 /// Parse the class CLI parameter.
 fn parse_class(input: &str) -> Result<Class, String> {
-    match input.find(',') {
-        Some(position) => {
-            let general = input[position + 1..].to_owned();
-
-            // Warn the user if they've passed too many values.
-            if general.contains(',') {
-                return Err(String::from("Too many parameters"));
-            }
-
-            Ok(Class { instance: input[..position].into(), general })
+    let (general, instance) = match input.split_once(',') {
+        // Warn the user if they've passed too many values.
+        Some((_, instance)) if instance.contains(',') => {
+            return Err(String::from("Too many parameters"))
         },
-        None => Ok(Class { instance: input.into(), general: DEFAULT_NAME.into() }),
-    }
+        Some((general, instance)) => (general, instance),
+        None => (input, input),
+    };
+
+    Ok(Class::new(general, instance))
 }
 
 /// Convert to hex if possible, else decimal
@@ -385,15 +382,15 @@ mod tests {
     #[test]
     fn parse_instance_class() {
         let class = parse_class("one").unwrap();
+        assert_eq!(class.general, "one");
         assert_eq!(class.instance, "one");
-        assert_eq!(class.general, DEFAULT_NAME);
     }
 
     #[test]
     fn parse_general_class() {
         let class = parse_class("one,two").unwrap();
-        assert_eq!(class.instance, "one");
-        assert_eq!(class.general, "two");
+        assert_eq!(class.general, "one");
+        assert_eq!(class.instance, "two");
     }
 
     #[test]
diff --git a/alacritty/src/config/window.rs b/alacritty/src/config/window.rs
index 8a59a007..80df87b7 100644
--- a/alacritty/src/config/window.rs
+++ b/alacritty/src/config/window.rs
@@ -203,13 +203,19 @@ pub struct Dimensions {
 /// Window class hint.
 #[derive(Serialize, Debug, Clone, PartialEq, Eq)]
 pub struct Class {
-    pub instance: String,
     pub general: String,
+    pub instance: String,
+}
+
+impl Class {
+    pub fn new(general: impl ToString, instance: impl ToString) -> Self {
+        Self { general: general.to_string(), instance: instance.to_string() }
+    }
 }
 
 impl Default for Class {
     fn default() -> Self {
-        Self { instance: DEFAULT_NAME.into(), general: DEFAULT_NAME.into() }
+        Self::new(DEFAULT_NAME, DEFAULT_NAME)
     }
 }
 
diff --git a/extra/alacritty.man b/extra/alacritty.man
index eec20d60..8848938a 100644
--- a/extra/alacritty.man
+++ b/extra/alacritty.man
@@ -32,10 +32,12 @@ Increases the level of verbosity (the max level is \fB\-vvv\fR)
 Prints version information
 .SH "OPTIONS"
 .TP
-\fB\-\-class\fR <instance> | <instance>,<general>
+\fB\-\-class\fR <general> | <general>,<instance>
 Defines the window class hint on Linux [default: Alacritty,Alacritty]
 
-On Wayland the instance class sets the `app_id`, while the general class is ignored.
+When only the general class is passed, instance will be set to the same value.
+
+On Wayland the general class sets the `app_id`, while the instance class is ignored.
 .TP
 \fB\-e\fR, \fB\-\-command\fR <command>...
 Command and args to execute (must be last argument)