fix: Linux 系统安装时游戏目录默认回退到用户主目录

从 deb 等系统包安装时，启动器可执行文件位于 /usr/bin，此前一键安装
StarLight 实例的"选择游戏目录"弹窗会默认到这个系统目录，普通用户既
无写权限，也不适合存放游戏数据。

将默认目录计算移入 theseus::default_game_dir_root()：Linux 下若可执行
文件位于 /usr、/opt、/snap 等系统路径，回退到用户主目录；便携版与其
他平台仍使用可执行文件所在目录。

Cargo.lock

@@ -6841,7 +6841,7 @@ dependencies = [
 
 [[package]]
 name = "theseus"
-version = "1.0.2-beta6"
+version = "1.0.2-beta7"
 dependencies = [
  "ariadne",
  "async-minecraft-ping",
@@ -6945,7 +6945,7 @@ dependencies = [
 
 [[package]]
 name = "theseus_gui"
-version = "1.0.2-beta6"
+version = "1.0.2-beta7"
 dependencies = [
  "ashpd",
  "async_zip",

apps/app-frontend/package.json

@@ -1,7 +1,7 @@
 {
 	"name": "@modrinth/app-frontend",
 	"private": true,
-	"version": "1.0.2-beta6",
+	"version": "1.0.2-beta7",
 	"type": "module",
 	"scripts": {
 		"dev": "vite",

apps/app/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "theseus_gui"
 # The actual version is set by the theseus-build workflow on tagging
-version = "1.0.2-beta6"
+version = "1.0.2-beta7"
 edition.workspace = true
 description = "Axolotl Launcher is a cross-platform Minecraft launcher"
 homepage = "https://www.ghs.red"

apps/app/src/main.rs

@@ -324,12 +324,9 @@ async fn initialize_state(app: tauri::AppHandle) -> api::Result<()> {
 /// external game-directory root for the one-click StarLight install flow.
 #[tauri::command]
 fn get_launcher_root_dir() -> api::Result<String> {
-    let exe = std::env::current_exe().map_err(|error| {
-        theseus::Error::from(theseus::ErrorKind::FSError(error.to_string()))
-    })?;
-    let dir = exe.parent().ok_or_else(|| {
+    let dir = theseus::default_game_dir_root().ok_or_else(|| {
         theseus::Error::from(theseus::ErrorKind::FSError(
-            "Launcher executable has no parent directory".to_string(),
+            "Could not determine a default game directory root".to_string(),
         ))
     })?;
     Ok(dir.to_string_lossy().into_owned())

packages/app-lib/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "theseus"
 # The actual version is set by the theseus-build workflow on tagging
-version = "1.0.2-beta6"
+version = "1.0.2-beta7"
 edition.workspace = true
 
 [dependencies]

packages/app-lib/src/lib.rs

@@ -39,7 +39,7 @@ pub use state::{DirectoryInfo, State};
 pub use storage::*;
 pub use util::fetch::build_proxied_client;
 pub use util::file_lock::{LockingProcess, get_locking_processes};
-pub use util::platform::is_process_elevated;
+pub use util::platform::{default_game_dir_root, is_process_elevated};
 pub use util::proxy::{ProxyConfig, ProxyMode, ProxyTestResult};
 pub use util::symlink::SymlinkCapability;
 

packages/app-lib/src/state/process.rs

@@ -713,16 +713,37 @@ impl Process {
 
                 pending.push_str(&String::from_utf8_lossy(&chunk[..read]));
 
-                // Drain every complete frame currently buffered.
-                while let Some(frame) = take_next_log4j_frame(&mut pending) {
-                    Self::handle_log4j_frame(
-                        instance_id,
-                        instance_name,
-                        process_id,
-                        log_path.as_ref(),
-                        &frame,
-                    )
-                    .await;
+                // Mods can write plain text to either pipe even when the
+                // launcher selected XML logging. Forward it as soon as a line
+                // is complete instead of retaining it until the game exits.
+                while let Some(output) = take_next_log_output(&mut pending) {
+                    match output {
+                        LogOutput::Xml(frame) => {
+                            Self::handle_log4j_frame(
+                                instance_id,
+                                instance_name,
+                                process_id,
+                                log_path.as_ref(),
+                                &frame,
+                            )
+                            .await;
+                        }
+                        LogOutput::Legacy(text) => {
+                            if let Err(e) =
+                                Self::append_to_log_file(&log_path, &text)
+                            {
+                                tracing::warn!(
+                                    "Failed to write to log file: {e}"
+                                );
+                            }
+                            if !text.trim_end().is_empty() {
+                                Self::emit_legacy_log(
+                                    instance_id,
+                                    text.trim_end(),
+                                );
+                            }
+                        }
+                    }
                 }
 
                 // Guard against a runaway buffer if no frame delimiters ever
@@ -1360,32 +1381,119 @@ impl Process {
         Ok(())
     }
 }
-/// Cuts the next complete `<log4j:Event …>…</log4j:Event>` frame out of the
-/// live buffer and returns it as an owned string, leaving any trailing partial
-/// frame in place.
-///
-/// Returns `None` when the buffer does not yet contain a full frame. This is a
-/// plain string operation on purpose: it never poisons any parser state, so a
-/// split or malformed frame on the live pipe cannot stop log forwarding.
-fn take_next_log4j_frame(buffer: &mut String) -> Option<String> {
+#[derive(Debug, Eq, PartialEq)]
+enum LogOutput {
+    Xml(String),
+    Legacy(String),
+}
+
+/// Drains complete XML frames or plain text in stream order. Partial frames
+/// and plain text lines remain buffered until their next chunk arrives.
+fn take_next_log_output(buffer: &mut String) -> Option<LogOutput> {
     const OPEN: &str = "<log4j:Event";
     const CLOSE: &str = "</log4j:Event>";
 
-    let start = buffer.find(OPEN)?;
-    // Discard anything before the frame (raw text, XML prolog, …).
-    if start > 0 {
-        buffer.drain(..start);
+    match buffer.find(OPEN) {
+        Some(0) => {
+            let close = buffer.find(CLOSE)?;
+            let end = close + CLOSE.len();
+            Some(LogOutput::Xml(buffer.drain(..end).collect()))
+        }
+        Some(start) => Some(LogOutput::Legacy(buffer.drain(..start).collect())),
+        None => {
+            let end = buffer.find('\n')? + 1;
+            Some(LogOutput::Legacy(buffer.drain(..end).collect()))
+        }
     }
-    let close = buffer.find(CLOSE)?;
-    let end = close + CLOSE.len();
-    let frame = buffer[..end].to_string();
-    buffer.drain(..end);
-    Some(frame)
 }
 #[cfg(test)]
 mod post_upgrade_tests {
     use super::*;
 
+    #[test]
+    fn mixed_log_output_keeps_partial_xml_and_multiline_messages() {
+        let mut pending = "raw\n<log4j:Ev".to_string();
+        assert_eq!(
+            take_next_log_output(&mut pending),
+            Some(LogOutput::Legacy("raw\n".into()))
+        );
+        assert_eq!(take_next_log_output(&mut pending), None);
+        pending.push_str("ent><log4j:Message><![CDATA[first\nsecond");
+        assert_eq!(take_next_log_output(&mut pending), None);
+        pending.push_str("]]></log4j:Message></log4j:Event>\nafter\n");
+        assert_eq!(take_next_log_output(&mut pending), Some(LogOutput::Xml("<log4j:Event><log4j:Message><![CDATA[first\nsecond]]></log4j:Message></log4j:Event>".into())));
+        assert_eq!(
+            take_next_log_output(&mut pending),
+            Some(LogOutput::Legacy("\n".into()))
+        );
+        assert_eq!(
+            take_next_log_output(&mut pending),
+            Some(LogOutput::Legacy("after\n".into()))
+        );
+        assert!(pending.is_empty());
+    }
+
+    #[tokio::test]
+    async fn xml_logging_forwards_plain_text_before_pipe_closes() {
+        use tokio::io::AsyncWriteExt;
+
+        let instance_id = Uuid::new_v4().to_string();
+        let directory = tempfile::tempdir().unwrap();
+        let log_path = directory.path().join("live.log");
+        let (mut writer, reader) = tokio::io::duplex(1024);
+        let output = Process::process_output(
+            &instance_id,
+            "instance",
+            "Instance",
+            "process",
+            reader,
+            &log_path,
+            true,
+        );
+        tokio::pin!(output);
+        writer.write_all(b"mod output\n").await.unwrap();
+        let forwarded = async {
+            loop {
+                if get_log_buffer(&instance_id) == ["mod output"] {
+                    break;
+                }
+                tokio::time::sleep(std::time::Duration::from_millis(5)).await;
+            }
+        };
+        tokio::select! {
+            _ = &mut output => panic!("reader ended while writer is still open"),
+            result = tokio::time::timeout(std::time::Duration::from_secs(1), forwarded) => {
+                result.expect("plain text was buffered until EOF");
+            }
+        }
+        assert_eq!(std::fs::read_to_string(&log_path).unwrap(), "mod output\n");
+        drop(writer);
+        output.await;
+        remove_log_buffer(&instance_id);
+    }
+
+    #[tokio::test]
+    async fn xml_logging_preserves_plain_text_before_xml_frames() {
+        let instance_id = Uuid::new_v4().to_string();
+        let directory = tempfile::tempdir().unwrap();
+        let log_path = directory.path().join("mixed.log");
+        let input = "mod output\n<log4j:Event level=\"INFO\"><log4j:Message><![CDATA[xml output]]></log4j:Message></log4j:Event>\n";
+        Process::process_output(
+            &instance_id,
+            "instance",
+            "Instance",
+            "process",
+            std::io::Cursor::new(input),
+            &log_path,
+            true,
+        )
+        .await;
+        let lines = get_log_buffer(&instance_id);
+        assert_eq!(lines.first().map(String::as_str), Some("mod output"));
+        assert!(lines.iter().any(|line| line.contains("xml output")));
+        remove_log_buffer(&instance_id);
+    }
+
     #[test]
     fn live_log_snapshot_sequences_batches_and_preserves_position_after_clear()
     {

packages/app-lib/src/util/platform.rs

@@ -1,5 +1,6 @@
 //! Platform-related code
 use daedalus::minecraft::{Os, OsRule};
+use std::path::PathBuf;
 
 /// (e.g. "Run as administrator" on Windows).
 #[cfg(target_os = "windows")]
@@ -143,3 +144,31 @@ pub fn classpath_separator(java_arch: &str) -> &'static str {
         Os::Windows | Os::WindowsArm64 => ";",
     }
 }
+
+/// Root directory used as the default for one-click StarLight instance
+/// installs. Portable builds live next to their executable, which is a fine
+/// place for game data. System installs (e.g. a Linux `.deb` under `/usr/bin`)
+/// do not, so fall back to the user's home directory there.
+pub fn default_game_dir_root() -> Option<PathBuf> {
+    let exe_dir = std::env::current_exe().ok()?.parent()?.to_path_buf();
+    if cfg!(target_os = "linux") && is_system_install_dir(&exe_dir) {
+        return dirs::home_dir();
+    }
+    Some(exe_dir)
+}
+
+#[cfg(target_os = "linux")]
+fn is_system_install_dir(path: &std::path::Path) -> bool {
+    const SYSTEM_PREFIXES: &[&str] = &[
+        "/usr/", "/opt/", "/snap/", "/bin/", "/sbin/", "/lib/", "/lib64/",
+    ];
+    let display = path.to_string_lossy();
+    SYSTEM_PREFIXES
+        .iter()
+        .any(|prefix| display.starts_with(prefix))
+}
+
+#[cfg(not(target_os = "linux"))]
+fn is_system_install_dir(_path: &std::path::Path) -> bool {
+    false
+}