fix: 修复从 .minecraft 导入实例的多项缺陷

修复从 .minecraft / PCL / HMCL 等启动器导入实例时的 6 个问题：

- 复制模式不再克隆 versions/ 下的所有实例，只保留选中的版本
- 版本隔离导入时把 .minecraft 根内容（mods/saves/config）与选中
  versions/<name> 合并进实例目录，不再得到纯原版实例
- 符号链接导入不再因 game_dir_override 被丢弃而在错误目录创建
  游戏数据，实例也不会在失败后被误删
- 不再将用户选择的版本隔离模式强行改为共享（InstallRequest::
  ImportInstance 的 game_dir_override 现在正确透传到导入逻辑）
- 清洗非标准加载器坐标（如 net.neoforged:neoforge:21.1.250:client]
  中的 :client] 后缀），并补充回归测试

涉及 api/pack/import 下的 generic/mod/instance_json 及各启动器
导入器，以及 install/runner 的调用点。

packages/app-lib/src/api/pack/import/atlauncher.rs

@@ -266,7 +266,9 @@ async fn import_atlauncher_unmanaged(
     let state = State::get().await?;
     finish_import(
         instance_id,
-        minecraft_folder,
+        Some(minecraft_folder),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/api/pack/import/axolotl.rs

@@ -170,7 +170,9 @@ pub(crate) async fn import_axolotl(
 
     finish_import(
         instance_id,
-        source_path,
+        Some(source_path),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/api/pack/import/curseforge.rs

@@ -221,7 +221,9 @@ pub async fn import_curseforge(
     let state = State::get().await?;
     finish_import(
         instance_id,
-        curseforge_instance_folder,
+        Some(curseforge_instance_folder),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/api/pack/import/gdlauncher.rs

@@ -118,7 +118,9 @@ pub async fn import_gdlauncher(
     let state = State::get().await?;
     finish_import(
         instance_id,
-        gdlauncher_instance_folder,
+        Some(gdlauncher_instance_folder),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/api/pack/import/generic.rs

@@ -3,7 +3,7 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use super::{ImportOverrides, instance_json};
+use super::{ImportOverrides, instance_json, resolve_import_game_root};
 use crate::{
     State,
     install::{InstallPhaseDetails, InstallProgressReporter},
@@ -29,29 +29,129 @@ pub async fn import_generic(
     overrides: &ImportOverrides,
     instance_path: Option<PathBuf>, // For compatible mode: path to versions/<version>/
 ) -> crate::Result<()> {
-    let (name, dotminecraft, json_path) = if let Some(ref inst_path) =
+    // Resolve the source layout. Three inputs describe the same import from
-        instance_path
+    // different angles and must be reconciled consistently:
-    {
+    //
-        let name = inst_path
+    // - `instance_folder`: the game root chosen by the caller (normally the
+    //   `.minecraft` root for a PCL/HMCL install, or the folder itself).
+    // - `instance_path`: when present, the specific `versions/<name>` folder
+    //   the user selected. A `.minecraft` root can hold many versions; only
+    //   this one belongs to the instance being imported.
+    // - `overrides.game_dir_override`: the user's explicit version-isolation
+    //   choice.
+    //
+    // The old behaviour copied/symlinked the whole `.minecraft` root and let
+    // the version folder dangle, which produced vanilla-only copies (mods
+    // stayed in versions/<name>) and cloned every sibling version too.
+    let layout = resolve_import_layout(
+        &instance_folder,
+        instance_path.as_deref(),
+        overrides.game_dir_override.as_deref(),
+    );
+
+    let info = detect_instance_info(&layout.json_source, overrides).await?;
+    register_instance(instance_id, &layout.name, &info).await?;
+    copy_instance_files(instance_id, &layout, reporter, details, symlink)
+        .await
+}
+
+/// The resolved source layout for a generic import.
+///
+/// `content_source` holds the shared game content (mods/saves/config) that
+/// belongs to the instance; `version_dir` is the selected `versions/<name>`
+/// folder. Both are merged into the instance directory by the copy/symlink
+/// stage, so a version-isolated import keeps the root-level mods it used to
+/// leave behind.
+struct ImportLayout {
+    /// Display name for the instance (the version folder name when isolated,
+    /// otherwise the game root folder name).
+    name: String,
+    /// Directory the version JSON is detected from.
+    json_source: PathBuf,
+    /// Directory whose game content (mods/saves/config) belongs to the
+    /// instance. For a shared root this is the root itself; for the "move the
+    /// root content into versions/<name>" isolation strategy this is still the
+    /// root, but its content is copied *into* the instance (which then becomes
+    /// the game dir).
+    content_source: Option<PathBuf>,
+    /// Selected `versions/<name>` folder, when the source is a shared root.
+    version_dir: Option<PathBuf>,
+    /// Whether the instance uses version isolation.
+    isolated: bool,
+}
+
+/// Reconciles the three import inputs into one layout.
+///
+/// Rules:
+/// - When `instance_path` is given it is the authoritative version folder; the
+///   instance is version-isolated unless the user explicitly asked to share.
+/// - When the user asked to share, the `.minecraft` root is the game dir.
+/// - Without a selected version folder, fall back to the old auto-detection so
+///   direct folder imports keep working.
+fn resolve_import_layout(
+    instance_folder: &Path,
+    selected_version: Option<&Path>,
+    game_dir_override: Option<&str>,
+) -> ImportLayout {
+    let root_name = instance_folder
+        .file_name()
+        .map(|n| n.to_string_lossy().to_string())
+        .unwrap_or_else(|| "imported".to_string());
+
+    // Explicit "version shared" choice: copy the whole `.minecraft` root.
+    let shared_forced = game_dir_override
+        .map(|dir| {
+            let normalized = dir.trim_end_matches(['/', '\\']);
+            normalized.eq_ignore_ascii_case(
+                instance_folder
+                    .to_string_lossy()
+                    .trim_end_matches(['/', '\\']),
+            )
+        })
+        .unwrap_or(false);
+
+    if let Some(version_dir) = selected_version {
+        let version_name = version_dir
             .file_name()
             .map(|n| n.to_string_lossy().to_string())
-            .unwrap_or_else(|| "imported".to_string());
+            .unwrap_or_else(|| root_name.clone());
-        tracing::debug!(
-            "import_generic: compatible mode - dotminecraft={}, json_path={}",
-            instance_folder.display(),
-            inst_path.display()
-        );
-        (name, instance_folder.to_path_buf(), inst_path.to_path_buf())
-    } else {
-        let (name, dotminecraft) = resolve_dotminecraft(&instance_folder);
-        let json_path = dotminecraft.clone(); // JSON detection will scan dotminecraft
-        (name, dotminecraft, json_path)
-    };
 
-    let info = detect_instance_info(&json_path, overrides).await?;
+        if shared_forced {
-    register_instance(instance_id, &name, &info).await?;
+            // User explicitly chose to share the `.minecraft` root even though
-    copy_instance_files(instance_id, &dotminecraft, reporter, details, symlink)
+            // a version folder was selected.
-        .await
+            return ImportLayout {
+                name: root_name,
+                json_source: version_dir.to_path_buf(),
+                content_source: Some(instance_folder.to_path_buf()),
+                version_dir: Some(version_dir.to_path_buf()),
+                isolated: false,
+            };
+        }
+
+        // Version-isolated strategy (甲): the instance becomes the game dir.
+        // The version files (`versions/<name>`) and the shared root content
+        // (mods/saves/config) are both merged into the instance, so mods that
+        // live at the `.minecraft` root survive the import instead of being
+        // left behind.
+        return ImportLayout {
+            name: version_name,
+            json_source: version_dir.to_path_buf(),
+            content_source: Some(instance_folder.to_path_buf()),
+            version_dir: Some(version_dir.to_path_buf()),
+            isolated: true,
+        };
+    }
+
+    // No explicit version folder: fall back to auto-detection.
+    let (name, dotminecraft) = resolve_dotminecraft(instance_folder);
+    let game_root = resolve_import_game_root(&dotminecraft);
+    ImportLayout {
+        name,
+        json_source: dotminecraft.clone(),
+        content_source: Some(game_root.clone()),
+        version_dir: None,
+        isolated: game_root != dotminecraft,
+    }
 }
 
 /// Stage 1 — resolve the name and the `.minecraft` directory of an imported
@@ -325,21 +425,30 @@ async fn resolve_loader_version(
 }
 
 /// Stage 4 — copy (or symlink) the source files into the instance profile.
+///
+/// Uses the reconciled [`ImportLayout`]: the shared content root (mods/saves/
+/// config) and the selected `versions/<name>` folder are both merged into the
+/// instance directory, so a version-isolated import keeps root-level content.
 async fn copy_instance_files(
     instance_id: &str,
-    dotminecraft: &Path,
+    layout: &ImportLayout,
     reporter: InstallProgressReporter,
     details: InstallPhaseDetails,
     symlink: bool,
 ) -> crate::Result<()> {
     let state = State::get().await?;
     tracing::debug!(
-        "import_generic: finishing import for instance_id={}",
+        "import_generic: finishing import for instance_id={} content_source={:?} version_dir={:?} isolated={}",
-        instance_id
+        instance_id,
+        layout.content_source,
+        layout.version_dir,
+        layout.isolated
     );
     finish_import(
         instance_id,
-        dotminecraft.to_path_buf(),
+        layout.content_source.clone(),
+        layout.version_dir.clone(),
+        layout.isolated,
         &state.io_semaphore,
         reporter,
         details,
@@ -399,6 +508,7 @@ mod tests {
             game_version: Some("1.20.1".to_string()),
             loader: Some(ModLoader::Fabric),
             loader_version: Some("0.15.11".to_string()),
+            ..Default::default()
         };
 
         let info = detect_instance_info(directory.path(), &overrides)
@@ -418,6 +528,7 @@ mod tests {
                 game_version: Some("1.20.1".to_string()),
                 loader: Some(ModLoader::Fabric),
                 loader_version: Some(loader_version.to_string()),
+                ..Default::default()
             };
 
             let info = detect_instance_info(directory.path(), &overrides)

packages/app-lib/src/api/pack/import/instance_json.rs

@@ -196,7 +196,8 @@ pub(crate) fn normalize_imported_loader_version(
     game_version: &str,
     detected_version: &str,
 ) -> String {
-    let detected_version = detected_version.trim();
+    let detected_version = sanitize_loader_version(detected_version);
+    let detected_version = detected_version.as_str();
     let without_family = match loader {
         "fabric" | "legacy_fabric" => detected_version
             .strip_prefix("fabric-loader-")
@@ -212,7 +213,7 @@ pub(crate) fn normalize_imported_loader_version(
     }
     .unwrap_or(detected_version);
 
-    match loader {
+    let normalized = match loader {
         "fabric" | "legacy_fabric" | "quilt" => without_family
             .strip_suffix(&format!("-{game_version}"))
             .unwrap_or(without_family)
@@ -232,7 +233,8 @@ pub(crate) fn normalize_imported_loader_version(
                 .to_string()
         }
         _ => without_family.to_string(),
-    }
+    };
+    sanitize_loader_version(&normalized)
 }
 
 fn extract_version(
@@ -575,6 +577,11 @@ fn detect_adjuncts(
 
 /// Extracts the loader version string from JSON content by finding a needle
 /// and reading until a terminator character.
+///
+/// The terminator set includes `:` `]` `[` and whitespace because non-standard
+/// launcher JSONs (notably PCL) may embed the loader coordinate in a composite
+/// string such as `net.neoforged:neoforge:21.1.250:client]`, where the real
+/// version ends at the first extra `:` rather than at the closing quote.
 fn try_extract_version_from_needle(
     content: &str,
     needle: &str,
@@ -582,17 +589,32 @@ fn try_extract_version_from_needle(
 ) -> Option<String> {
     let pos = content.find(needle)?;
     let after = &content[pos + needle.len()..];
-    let end = after.find(&['"', ',', '\n', '}'] as &[char])?;
+    let end = after
+        .find(&['"', ',', '\n', '}', ']', '[', ':', ' '] as &[char])?;
     let ver = &after[..end];
     if let Some(ch) = split_at
         && let Some(pos) = ver.rfind(ch)
     {
-        Some(ver[pos + 1..].to_string())
+        Some(sanitize_loader_version(&ver[pos + 1..]))
     } else {
-        Some(ver.to_string())
+        Some(sanitize_loader_version(ver))
     }
 }
 
+/// Trims junk that non-standard launcher JSONs append to a loader coordinate
+/// (e.g. `21.1.250:client]`, `44.0.3 ` or `0.15.11\n`). Keeps only the leading
+/// version token so the metadata resolver receives a clean id.
+fn sanitize_loader_version(raw: &str) -> String {
+    let trimmed = raw.trim();
+    // Cut at the first character that cannot appear in a loader version id.
+    let end = trimmed
+        .find(|ch: char| {
+            !(ch.is_ascii_alphanumeric() || ch == '.' || ch == '-' || ch == '_' || ch == '+')
+        })
+        .unwrap_or(trimmed.len());
+    trimmed[..end].trim().to_string()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -837,4 +859,35 @@ mod tests {
         assert_eq!(info.loader.as_deref(), Some("fabric"));
         assert_eq!(info.loader_version.as_deref(), Some("0.15.11"));
     }
+
+    #[test]
+    fn sanitizes_loader_version_with_launcher_suffix() {
+        // PCL and other launchers may embed composite coordinates such as
+        // `net.neoforged:neoforge:21.1.250:client]`; the extracted version must
+        // stop at the first extra `:` instead of swallowing `:client]`.
+        assert_eq!(sanitize_loader_version("21.1.250:client]"), "21.1.250");
+        assert_eq!(sanitize_loader_version("44.0.3 "), "44.0.3");
+        assert_eq!(sanitize_loader_version("0.15.11\n"), "0.15.11");
+        assert_eq!(sanitize_loader_version("1.21.1-52.0.0"), "1.21.1-52.0.0");
+        assert_eq!(
+            sanitize_loader_version("1.7.10-10.13.4.1614-1.7.10"),
+            "1.7.10-10.13.4.1614-1.7.10"
+        );
+    }
+
+    #[test]
+    fn detect_loader_version_stops_at_extra_colon() {
+        assert_loader(
+            r#"{
+                "id": "1.21.1-neoforge-21.1.250",
+                "libraries": [
+                    {
+                        "name": "net.neoforged:neoforge:21.1.250:client]"
+                    }
+                ]
+            }"#,
+            "neoforge",
+            Some("21.1.250"),
+        );
+    }
 }

packages/app-lib/src/api/pack/import/mmc.rs

@@ -303,7 +303,9 @@ async fn import_mmc_unmanaged(
     let state = State::get().await?;
     finish_import(
         instance_id,
-        minecraft_folder,
+        Some(minecraft_folder),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/api/pack/import/mod.rs

@@ -661,6 +661,10 @@ pub(crate) struct ImportOverrides {
     pub game_version: Option<String>,
     pub loader: Option<ModLoader>,
     pub loader_version: Option<String>,
+    /// The user's explicit game directory (version isolation choice). When set,
+    /// it is the absolute path the instance should use as its working
+    /// directory; when `None`, the layout is auto-detected.
+    pub game_dir_override: Option<String>,
 }
 
 pub(crate) async fn import_instance_with_reporter(
@@ -1045,7 +1049,9 @@ pub async fn recache_icon(
 
 pub(crate) async fn copy_dotminecraft_with_reporter(
     instance_id: &str,
-    dotminecraft: PathBuf,
+    content_source: Option<PathBuf>,
+    version_dir: Option<PathBuf>,
+    isolated: bool,
     io_semaphore: &IoSemaphore,
     reporter: InstallProgressReporter,
     details: InstallPhaseDetails,
@@ -1053,7 +1059,36 @@ pub(crate) async fn copy_dotminecraft_with_reporter(
     let instance_path =
         crate::api::instance::get_full_path(instance_id).await?;
 
-    let files = collect_dotminecraft_files(&dotminecraft).await?;
+    let mut files: Vec<(PathBuf, PathBuf)> = Vec::new();
+
+    if let Some(content_root) = &content_source {
+        // Copy the shared content (mods/saves/config/…). When a specific
+        // version folder is in play, every sibling under `versions/` belongs to
+        // a different instance and must not be cloned here.
+        //
+        // - shared import: keep the selected version, drop the rest;
+        // - isolated import (甲): drop the whole `versions/` tree here — the
+        //   selected version is copied separately below and merged into the
+        //   instance root.
+        let keep_version = if isolated {
+            None
+        } else {
+            version_dir.as_deref()
+        };
+        let mut content_files =
+            collect_dotminecraft_files(content_root, keep_version, isolated)
+                .await?;
+        files.append(&mut content_files);
+    }
+
+    if isolated && let Some(version) = &version_dir {
+        // Merge the selected version files (`<name>.json`, `<name>.jar`, and any
+        // nested `mods/`, `config/`, … that live inside the version folder)
+        // directly into the instance root so the instance directory becomes a
+        // self-contained game dir.
+        let mut version_files = collect_version_files(version).await?;
+        files.append(&mut version_files);
+    }
 
     let total = files.len() as u64;
     if total == 0 {
@@ -1085,6 +1120,8 @@ pub(crate) async fn copy_dotminecraft_with_reporter(
 /// at the source root (`<dirname>.json` and `<dirname>.jar`).
 async fn collect_dotminecraft_files(
     dotminecraft: &Path,
+    keep_version: Option<&Path>,
+    isolated: bool,
 ) -> crate::Result<Vec<(PathBuf, PathBuf)>> {
     // Collect all files recursively
     let files = get_all_subfiles(dotminecraft, false).await?;
@@ -1098,6 +1135,14 @@ async fn collect_dotminecraft_files(
     let skip_json = format!("{dirname}.json");
     let skip_jar = format!("{dirname}.jar");
 
+    // When a specific version folder is requested from a shared `.minecraft`
+    // root, every other entry under `versions/` belongs to a different
+    // instance. Resolve the relative keep-path once so the loop can compare
+    // cheaply (e.g. `versions/1.21.1-NeoForge_21.1.250`).
+    let keep_relative = keep_version
+        .and_then(|version| version.strip_prefix(dotminecraft).ok())
+        .map(|rel| rel.to_path_buf());
+
     let mut collected = Vec::new();
     for abs_path in files {
         let metadata = tokio::fs::symlink_metadata(&abs_path)
@@ -1117,6 +1162,23 @@ async fn collect_dotminecraft_files(
         else {
             continue;
         };
+
+        // In the isolated strategy the whole `versions/` tree is handled
+        // separately (only the selected version is copied, and it is merged
+        // into the instance root), so skip it entirely here to avoid cloning
+        // sibling versions.
+        if isolated {
+            if rel.components().next().map(|c| c.as_os_str())
+                == Some("versions".as_ref())
+            {
+                continue;
+            }
+        } else if let Some(keep) = &keep_relative
+            && is_other_version_entry(&rel, keep)
+        {
+            continue;
+        }
+
         if rel
             .parent()
             .is_some_and(|path| !path.as_os_str().is_empty())
@@ -1132,6 +1194,70 @@ async fn collect_dotminecraft_files(
     Ok(collected)
 }
 
+/// Collects every file inside a selected `versions/<name>` folder, mapping each
+/// path relative to that folder so the contents merge directly into the
+/// instance root (the instance becomes a self-contained, version-isolated game
+/// dir).
+async fn collect_version_files(
+    version_dir: &Path,
+) -> crate::Result<Vec<(PathBuf, PathBuf)>> {
+    let files = get_all_subfiles(version_dir, false).await?;
+    let mut collected = Vec::new();
+    for abs_path in files {
+        let metadata = tokio::fs::symlink_metadata(&abs_path)
+            .await
+            .map_err(|error| IOError::with_path(error, &abs_path))?;
+        if crate::util::io::is_symlink_or_reparse(&metadata) {
+            tracing::warn!(
+                path = %abs_path.display(),
+                "Skipping nested symlink or reparse point while copying a version folder"
+            );
+            continue;
+        }
+        if let Ok(rel) = abs_path.strip_prefix(version_dir) {
+            collected.push((abs_path, rel.to_path_buf()));
+        }
+    }
+    Ok(collected)
+}
+
+/// True if `rel` lives under `versions/` but does not belong to the selected
+/// version folder `keep` (which is itself relative to the `.minecraft` root,
+/// e.g. `versions/1.21.1-NeoForge_21.1.250`).
+///
+/// `rel` may be the version directory itself, a file directly inside it, or a
+/// path nested deeper. Anything sharing the first two path components with
+/// `keep` is kept; every other `versions/<other>` entry is excluded.
+fn is_other_version_entry(rel: &Path, keep: &Path) -> bool {
+    let mut rel_components = rel.components();
+    let mut keep_components = keep.components();
+
+    // Both must start with the literal `versions` component.
+    if rel_components.next().map(|c| c.as_os_str()) != Some("versions".as_ref()) {
+        return false;
+    }
+    if keep_components.next().map(|c| c.as_os_str()) != Some("versions".as_ref()) {
+        return false;
+    }
+
+    let rel_version = rel_components.next().map(|c| c.as_os_str());
+    let keep_version = keep_components.next().map(|c| c.as_os_str());
+
+    // `rel` is always a *file* path relative to the `.minecraft` root. A file
+    // that sits directly under `versions/` (e.g. `versions/version_manifest.json`)
+    // has exactly two components and is shared metadata, not a version folder:
+    // leave it alone. Only when there is at least a third component
+    // (`versions/<name>/<file>`) can the second component be treated as a
+    // version directory name.
+    let rel_is_inside_version_dir = rel_components.next().is_some();
+
+    match (rel_version, keep_version) {
+        (Some(rel_v), Some(keep_v)) if rel_is_inside_version_dir => rel_v != keep_v,
+        // A file directly under `versions/`, shared metadata: keep it.
+        _ => false,
+    }
+}
+
 /// Copies the collected files into the instance profile concurrently, bounded
 /// by the I/O semaphore, reporting progress after every completed file.
 async fn copy_files_with_progress(
@@ -1225,7 +1351,7 @@ async fn copy_files_with_progress(
 /// back to the source folder itself: the game creates the content folders
 /// there on first run, and for imports the user's explicit game-dir choice
 /// (or no override, i.e. the managed symlink) decides the rest.
-fn resolve_import_game_root(source: &Path) -> PathBuf {
+pub(crate) fn resolve_import_game_root(source: &Path) -> PathBuf {
     // The source is itself the game root: either a whole Minecraft folder that
     // carries a game body, or any folder that already holds game content
     // (a version-isolated `versions/<name>` with mods/saves/config inside).
@@ -1300,19 +1426,27 @@ fn dir_has_game_content(root: &Path) -> bool {
 
 pub(crate) async fn finish_import(
     instance_id: &str,
-    dotminecraft: PathBuf,
+    content_source: Option<PathBuf>,
+    version_dir: Option<PathBuf>,
+    isolated: bool,
     io_semaphore: &IoSemaphore,
     reporter: InstallProgressReporter,
     details: InstallPhaseDetails,
     symlink: bool,
 ) -> crate::Result<()> {
-    let local_source = LocalRuntimeSource::discover(&dotminecraft);
+    // The directory the game body / version JSON lives in, used to discover the
+    // local runtime source. Prefer the selected version folder, else the
+    // content root.
+    let primary_source = version_dir
+        .clone()
+        .or_else(|| content_source.clone())
+        .ok_or_else(|| {
+            crate::ErrorKind::InputError(
+                "Import has no content source".to_string(),
+            )
+        })?;
+    let local_source = LocalRuntimeSource::discover(&primary_source);
 
-    // Respect an explicitly chosen game-dir override (the user's isolated /
-    // not-isolated selection, already stored on the instance row at creation).
-    // Only fall back to auto-detection for symlink imports that did not carry
-    // an explicit override, so copy imports always stay built-in (no override)
-    // and the frontend's choice is never clobbered.
     let state = crate::state::State::get().await?;
     let pool = &state.pool;
     let existing_override =
@@ -1324,17 +1458,15 @@ pub(crate) async fn finish_import(
         .map(|(_, override_dir)| override_dir)
         .unwrap_or(None);
     if existing_override.is_none() && symlink {
-        // For a non-version-isolated import the game content (mods, saves, config)
+        // For a symlinked import the game dir is the referenced source root,
-        // lives in the `.minecraft` root, not in the detected `versions/<name>`
+        // not the empty managed instance folder. Record it so the instance
-        // subfolder. Detect that and record the override so the instance uses the
+        // launches from the real location.
-        // real game root directly instead of an empty version subfolder.
+        if let Some(content_root) = &content_source {
-        let game_root = resolve_import_game_root(&dotminecraft);
-        if game_root != dotminecraft {
             crate::state::edit_instance(
                 instance_id,
                 crate::state::EditInstance {
                     game_dir_override: Some(Some(
-                        game_root.to_string_lossy().to_string(),
+                        content_root.to_string_lossy().to_string(),
                     )),
                     ..Default::default()
                 },
@@ -1345,6 +1477,11 @@ pub(crate) async fn finish_import(
     }
 
     if symlink {
+        let source_root = content_source.clone().ok_or_else(|| {
+            crate::ErrorKind::InputError(
+                "Symlink import requires a content source".to_string(),
+            )
+        })?;
         let state = State::get().await?;
         let relative_path =
             instance_rows::get_instance_path_by_id(instance_id, &state.pool)
@@ -1354,7 +1491,7 @@ pub(crate) async fn finish_import(
                 })?;
         // The instance's managed folder lives at instances_dir/<path>. This is
         // where the symlink is created; it must NOT go through the game-dir
-        // override (which points at the external .minecraft root).
+        // override (which points at the external source root).
         let instance_path =
             state.directories.instances_dir().join(&relative_path);
 
@@ -1402,7 +1539,7 @@ pub(crate) async fn finish_import(
                 return Err(error.into());
             }
             if let Err(error) =
-                io::create_symlink(&dotminecraft, &instance_path).await
+                io::create_symlink(&source_root, &instance_path).await
             {
                 let _ = io::rename_or_move(&backup_path, &instance_path).await;
                 watch_instance_folder(
@@ -1423,14 +1560,14 @@ pub(crate) async fn finish_import(
             )
             .await;
         } else {
-            io::create_symlink(&dotminecraft, &instance_path).await?;
+            io::create_symlink(&source_root, &instance_path).await?;
         }
 
         crate::state::edit_instance(
             instance_id,
             crate::state::EditInstance {
                 symlink_target: Some(Some(
-                    dotminecraft.to_string_lossy().to_string(),
+                    source_root.to_string_lossy().to_string(),
                 )),
                 ..Default::default()
             },
@@ -1440,7 +1577,9 @@ pub(crate) async fn finish_import(
     } else {
         copy_dotminecraft_with_reporter(
             instance_id,
-            dotminecraft,
+            content_source,
+            version_dir,
+            isolated,
             io_semaphore,
             reporter.clone(),
             details,

packages/app-lib/src/api/pack/import/modrinth_app.rs

@@ -210,7 +210,9 @@ pub async fn import_instance(
     let state = State::get().await?;
     finish_import(
         instance_id,
-        source,
+        Some(source),
+        None,
+        false,
         &state.io_semaphore,
         reporter,
         details,

packages/app-lib/src/install/runner.rs

@@ -1529,10 +1529,10 @@ async fn run_request(
             game_version,
             loader,
             loader_version,
-            game_dir_override: _,
+            game_dir_override,
         } => {
             tracing::debug!(
-                "InstallRequest::ImportInstance: launcher_type={launcher_type} base_path={} instance_folder={instance_folder} symlink={symlink}",
+                "InstallRequest::ImportInstance: launcher_type={launcher_type} base_path={} instance_folder={instance_folder} symlink={symlink} game_dir_override={game_dir_override:?}",
                 base_path.display()
             );
             let Some(instance_id) = current_instance_id(job_state) else {
@@ -1562,6 +1562,7 @@ async fn run_request(
                     game_version,
                     loader,
                     loader_version,
+                    game_dir_override,
                 },
                 // TODO(B2): apply overrides to launcher-specific importers
                 // (MultiMC/Prism/ATLauncher/GDLauncher/Curseforge/ModrinthApp);
@@ -1590,8 +1591,12 @@ async fn run_request(
             let state = State::get().await?;
             crate::api::pack::import::copy_dotminecraft_with_reporter(
                 &instance_id,
-                crate::api::instance::get_full_path(&source_instance_id)
+                Some(
-                    .await?,
+                    crate::api::instance::get_full_path(&source_instance_id)
+                        .await?,
+                ),
+                None,
+                false,
                 &state.io_semaphore,
                 InstallProgressReporter::new(job_id, job_state.clone()),
                 InstallPhaseDetails::Empty,
@@ -2526,7 +2531,9 @@ async fn copy_physical_instance_contents(
     )?;
     crate::api::pack::import::copy_dotminecraft_with_reporter(
         target_instance_id,
-        source_path,
+        Some(source_path),
+        None,
+        false,
         &state.io_semaphore,
         InstallProgressReporter::new(job_id, job_state.clone()),
         InstallPhaseDetails::Empty,