bg3: tolerate dangling Wine-prefix symlinks in metadata dirs

When the BG3 metadata path (e.g. AppData/Local/Larian Studios) is a
symlink left over from a previous prefix setup that points at a Steam
compatdata path which no longer resolves, pathlib's
mkdir(parents=True, exist_ok=True) raises FileExistsError — exist_ok
only suppresses the error when the path is an actual directory, and a
dangling symlink fails is_dir(). The launch crashed in
bg3_file_mapper.create_mapping before any mods were deployed.

Walk the path top-down on FileExistsError. For each component that's a
dangling symlink, resolve its target via os.path.realpath and create
the directory there so the symlink becomes valid and the original
mkdir succeeds. Cross-prefix sharing (the reason these symlinks exist)
is preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

1 files changed, 23 insertions, 4 deletions

diff --git a/libs/basic_games/games/baldursgate3/bg3_utils.py b/libs/basic_games/games/baldursgate3/bg3_utils.py
index bbe5cda..23f0a8c 100644
--- a/libs/basic_games/games/baldursgate3/bg3_utils.py
+++ b/libs/basic_games/games/baldursgate3/bg3_utils.py
@@ -1,4 +1,5 @@
 import functools
+import os
 import shutil
 import typing
 from pathlib import Path
@@ -262,8 +263,26 @@ class BG3Utils:
 
 
 def create_dir_if_needed(path: Path) -> Path:
-    if "." not in path.name[1:]:
-        path.mkdir(parents=True, exist_ok=True)
-    else:
-        path.parent.mkdir(parents=True, exist_ok=True)
+    target = path if "." not in path.name[1:] else path.parent
+    _mkdir_resolving_symlinks(target)
     return path
+
+
+def _mkdir_resolving_symlinks(target: Path) -> None:
+    try:
+        target.mkdir(parents=True, exist_ok=True)
+        return
+    except FileExistsError:
+        pass
+    # A component along the chain exists but is not a directory — typically a
+    # dangling symlink left over from a Wine prefix that points at a Steam
+    # compatdata path that doesn't exist yet. Walk top-down, materialize each
+    # dangling-symlink target as a real directory, then retry.
+    for component in list(reversed(target.parents)) + [target]:
+        if component.is_dir():
+            continue
+        if component.is_symlink():
+            real = Path(os.path.realpath(component))
+            real.mkdir(parents=True, exist_ok=True)
+            continue
+        component.mkdir(exist_ok=True)