feat(config): add evdev_modifier_delay option

espanso-config/src/config/mod.rs

@@ -108,6 +108,12 @@ pub trait Config: Send + Sync {
   // application is missing some key events.
   fn key_delay(&self) -> Option<usize>;
 
+  // Extra delay to apply when injecting modifiers under the EVDEV backend.
+  // This is useful on Wayland if espanso is injecting seemingly random
+  // cased letters, for example "Hi theRE1" instead of "Hi there!".
+  // Increase if necessary, decrease to speed up the injection.
+  fn evdev_modifier_delay(&self) -> Option<usize>;
+
   // Chars that when pressed mark the start and end of a word.
   // Examples of this are . or ,
   fn word_separators(&self) -> Vec<String>;

espanso-config/src/config/parse/mod.rs

@@ -52,6 +52,7 @@ pub(crate) struct ParsedConfig {
   pub inject_delay: Option<usize>,
   pub key_delay: Option<usize>,
   pub keyboard_layout: Option<BTreeMap<String, String>>,
+  pub evdev_modifier_delay: Option<usize>,
 
   // Includes
   pub includes: Option<Vec<String>>,

espanso-config/src/config/parse/yaml.rs

@@ -73,6 +73,9 @@ pub(crate) struct YAMLConfig {
   #[serde(default)]
   pub backspace_delay: Option<usize>,
 
+  #[serde(default)]
+  pub evdev_modifier_delay: Option<usize>,
+
   #[serde(default)]
   pub word_separators: Option<Vec<String>>,
 
@@ -165,6 +168,7 @@ impl TryFrom<YAMLConfig> for ParsedConfig {
       disable_x11_fast_inject: yaml_config.disable_x11_fast_inject,
       inject_delay: yaml_config.inject_delay,
       key_delay: yaml_config.key_delay.or(yaml_config.backspace_delay),
+      evdev_modifier_delay: yaml_config.evdev_modifier_delay,
       word_separators: yaml_config.word_separators,
       backspace_limit: yaml_config.backspace_limit,
       apply_patch: yaml_config.apply_patch,
@@ -232,6 +236,7 @@ mod tests {
     inject_delay: 10
     key_delay: 20
     backspace_delay: 30
+    evdev_modifier_delay: 40
     word_separators: ["'", "."]
     backspace_limit: 10
     apply_patch: false
@@ -301,6 +306,7 @@ mod tests {
         win32_exclude_orphan_events: Some(false),
 
         pre_paste_delay: Some(300),
+        evdev_modifier_delay: Some(40),
 
         toggle_key: Some("CTRL".to_string()),
         word_separators: Some(vec!["'".to_owned(), ".".to_owned()]),

espanso-config/src/config/resolve.rs

@@ -17,16 +17,7 @@
  * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-use super::{
-  default::{
-    DEFAULT_CLIPBOARD_THRESHOLD, DEFAULT_PRE_PASTE_DELAY, DEFAULT_RESTORE_CLIPBOARD_DELAY,
-    DEFAULT_SHORTCUT_EVENT_DELAY,
-  },
-  parse::ParsedConfig,
-  path::calculate_paths,
-  util::os_matches,
-  AppProperties, Backend, Config, RMLVOConfig, ToggleKey,
-};
+use super::{AppProperties, Backend, Config, RMLVOConfig, ToggleKey, default::{DEFAULT_CLIPBOARD_THRESHOLD, DEFAULT_PRE_PASTE_DELAY, DEFAULT_RESTORE_CLIPBOARD_DELAY, DEFAULT_SHORTCUT_EVENT_DELAY}, parse::ParsedConfig, path::calculate_paths, util::os_matches};
 use crate::{counter::next_id, merge};
 use anyhow::Result;
 use log::error;
@@ -314,6 +305,10 @@ impl Config for ResolvedConfig {
   fn win32_exclude_orphan_events(&self) -> bool {
     self.parsed.win32_exclude_orphan_events.unwrap_or(true)
   }
+
+  fn evdev_modifier_delay(&self) -> Option<usize> {
+    self.parsed.evdev_modifier_delay
+  }
 }
 
 impl ResolvedConfig {
@@ -385,6 +380,7 @@ impl ResolvedConfig {
       toggle_key,
       inject_delay,
       key_delay,
+      evdev_modifier_delay,
       word_separators,
       backspace_limit,
       keyboard_layout,

espanso-config/src/legacy/mod.rs

@@ -390,6 +390,10 @@ impl Config for LegacyInteropConfig {
   fn win32_exclude_orphan_events(&self) -> bool {
     true
   }
+  
+  fn evdev_modifier_delay(&self) -> Option<usize> {
+    Some(10)
+  }
 }
 
 struct LegacyMatchGroup {