feat: support supplementary environment variables for hooks in App (#5916)

* feat: Implement launcher supplementary environmental variables, and env var substitution in hooks

* lint fix, prettier reformat

* descriptions added for each environment variable for hook settings

* alphabetize language keys

---------

Co-authored-by: Prospector <6166773+Prospector@users.noreply.github.com>

packages/app-lib/src/api/instance/run.rs

@@ -79,15 +79,95 @@ async fn run_credentials(
         .into());
     }
 
-    let pre_launch_hooks = context
+    let pre_launch_hook = context
         .launch_overrides
         .hooks
         .pre_launch
         .as_ref()
         .or(settings.hooks.pre_launch.as_ref())
         .filter(|hook_command| !hook_command.is_empty());
-    if let Some(hook) = pre_launch_hooks {
-        let mut cmd = shlex::split(hook)
+
+    let java_args = context
+        .launch_overrides
+        .extra_launch_args
+        .clone()
+        .unwrap_or(settings.extra_launch_args);
+
+    let wrapper = context
+        .launch_overrides
+        .hooks
+        .wrapper
+        .clone()
+        .or(settings.hooks.wrapper)
+        .filter(|hook_command| !hook_command.is_empty());
+
+    let env_args = context
+        .launch_overrides
+        .custom_env_vars
+        .clone()
+        .unwrap_or(settings.custom_env_vars);
+
+    let post_exit_hook = context
+        .launch_overrides
+        .hooks
+        .post_exit
+        .clone()
+        .or(settings.hooks.post_exit)
+        .filter(|hook_command| !hook_command.is_empty());
+
+    let memory = context.launch_overrides.memory.unwrap_or(settings.memory);
+    let resolution = context
+        .launch_overrides
+        .game_resolution
+        .unwrap_or(settings.game_resolution);
+    let has_hook_commands = pre_launch_hook.is_some()
+        || wrapper.is_some()
+        || post_exit_hook.is_some();
+    let full_path = if has_hook_commands {
+        Some(crate::util::io::canonicalize(
+            state
+                .directories
+                .instances_dir()
+                .join(&context.instance.path),
+        )?)
+    } else {
+        None
+    };
+    let hook_environment = if has_hook_commands {
+        let full_path = full_path
+            .as_ref()
+            .expect("hooked launches always resolve their instance path");
+        let java_version =
+            crate::launcher::resolve_java_for_launch(&context).await?;
+
+        Some(crate::launcher::hooks::HookEnvironment::from_current_env(
+            &env_args,
+            crate::launcher::hooks::HookVariables {
+                instance_name: context.instance.name.clone(),
+                instance_id: context.instance.path.clone(),
+                instance_dir: full_path.to_string_lossy().to_string(),
+                java_path: java_version.path.clone(),
+                java_args: crate::launcher::hooks::build_hook_java_args(
+                    &java_args,
+                    memory,
+                    &java_version,
+                ),
+            },
+        ))
+    } else {
+        None
+    };
+    let launch_env_args = hook_environment
+        .as_ref()
+        .map_or_else(|| env_args.clone(), |env| env.injected_envs());
+
+    if let (Some(hook), Some(hook_environment), Some(full_path)) = (
+        pre_launch_hook,
+        hook_environment.as_ref(),
+        full_path.as_ref(),
+    ) {
+        let expanded_hook = hook_environment.expand(hook);
+        let mut cmd = shlex::split(&expanded_hook)
             .ok_or_else(|| {
                 crate::ErrorKind::LauncherError(format!(
                     "Invalid pre-launch command: {hook}",
@@ -96,17 +176,12 @@ async fn run_credentials(
             .into_iter();
 
         if let Some(command) = cmd.next() {
-            let full_path = crate::util::io::canonicalize(
-                state
-                    .directories
-                    .instances_dir()
-                    .join(&context.instance.path),
-            )?;
             let result = Command::new(command)
                 .args(cmd)
-                .current_dir(&full_path)
+                .envs(launch_env_args.iter().cloned())
+                .current_dir(full_path)
                 .spawn()
-                .map_err(|e| IOError::with_path(e, &full_path))?
+                .map_err(|e| IOError::with_path(e, full_path))?
                 .wait()
                 .await
                 .map_err(IOError::from)?;
@@ -121,34 +196,19 @@ async fn run_credentials(
         }
     }
 
-    let java_args = context
-        .launch_overrides
-        .extra_launch_args
-        .clone()
-        .unwrap_or(settings.extra_launch_args);
-    let wrapper = context
-        .launch_overrides
-        .hooks
-        .wrapper
-        .clone()
-        .or(settings.hooks.wrapper)
+    let wrapper = wrapper
+        .map(|hook| {
+            hook_environment
+                .as_ref()
+                .map_or(hook.clone(), |env| env.expand(&hook))
+        })
         .filter(|hook_command| !hook_command.is_empty());
-    let memory = context.launch_overrides.memory.unwrap_or(settings.memory);
-    let resolution = context
-        .launch_overrides
-        .game_resolution
-        .unwrap_or(settings.game_resolution);
-    let env_args = context
-        .launch_overrides
-        .custom_env_vars
-        .clone()
-        .unwrap_or(settings.custom_env_vars);
-    let post_exit_hook = context
-        .launch_overrides
-        .hooks
-        .post_exit
-        .clone()
-        .or(settings.hooks.post_exit)
+    let post_exit_hook = post_exit_hook
+        .map(|hook| {
+            hook_environment
+                .as_ref()
+                .map_or(hook.clone(), |env| env.expand(&hook))
+        })
         .filter(|hook_command| !hook_command.is_empty());
 
     let mut mc_set_options: Vec<(String, String)> = vec![];
@@ -210,7 +270,7 @@ async fn run_credentials(
     crate::minecraft_skins::flush_pending_skin_change().await?;
     crate::launcher::launch_minecraft(
         &java_args,
-        &env_args,
+        &launch_env_args,
         &mc_set_options,
         &wrapper,
         &memory,