Fixed dead network mounts freezing folder listing in Browser.py

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Browser.py

@@ -277,6 +277,8 @@ class Browser(ft.Row):
         # entries make the cache meaningless.
         self.ColumnCells: dict[str, list[ft.Container]] = {}
         self.MetadataCache: dict[Path, tuple[float, dict[str, str]]] = {}
+        # Filled by _BuildEntries from the directory listing itself, see _IsDir.
+        self.EntryIsDir: dict[Path, bool] = {}
         self.FolderIconOverrides: dict[Path, FolderIconOverride] = LoadFolderIconOverrides()
         # Bumped by _RefreshEntries every time it rebuilds the list, so a
         # background _PopulateEntriesAsync pass from a superseded build can
@@ -1138,12 +1140,14 @@ class Browser(ft.Row):
         blocking on it. _PopulateEntriesAsync fills the real values in
         afterwards, off the UI thread. A cache hit (e.g. a same-directory
         refresh after a rename) still shows immediately, no flicker."""
+        Cached = self.MetadataCache.get(Entry)
+        if Cached is None:
+            return {}  # don't stat on a miss: a dead network mount blocks for ~20s
         try:
             Mtime = Entry.stat().st_mtime
         except OSError:
             return {}
-        Cached = self.MetadataCache.get(Entry)
-        if Cached is not None and Cached[0] == Mtime:
+        if Cached[0] == Mtime:
             return Cached[1]
         return {}
 
@@ -1197,7 +1201,7 @@ class Browser(ft.Row):
         pass resolves the real icon. Identical to _LeadingFor's non-
         thumbnail branches, so only images visibly change once their
         thumbnail loads — everything else never flickers."""
-        if Entry.is_dir():
+        if self._IsDir(Entry):
             return self._ResolveFolderIconFast(Entry, Size)
         return ft.Icon(ft.Icons.INSERT_DRIVE_FILE_OUTLINED, size=Size, color=Palette.Overlay0)
 
@@ -1273,7 +1277,7 @@ class Browser(ft.Row):
             NameKey = Entry.name.lower()
             if Field == "Size":
                 try:
-                    Primary = 0 if Entry.is_dir() else Entry.stat().st_size
+                    Primary = 0 if self._IsDir(Entry) else Entry.stat().st_size
                 except OSError:
                     Primary = 0
             elif Field == "Modified":
@@ -1282,16 +1286,24 @@ class Browser(ft.Row):
                 except OSError:
                     Primary = 0.0
             elif Field == "Type":
-                Primary = "" if Entry.is_dir() else Entry.suffix.lower()
+                Primary = "" if self._IsDir(Entry) else Entry.suffix.lower()
             else:  # "Name"
                 Primary = NameKey
             return (Primary, NameKey)
 
         Reverse = not self.Config.SortAscending
-        Dirs = sorted((E for E in Entries if E.is_dir()), key=KeyFn, reverse=Reverse)
-        Files = sorted((E for E in Entries if not E.is_dir()), key=KeyFn, reverse=Reverse)
+        Dirs = sorted((E for E in Entries if self._IsDir(E)), key=KeyFn, reverse=Reverse)
+        Files = sorted((E for E in Entries if not self._IsDir(E)), key=KeyFn, reverse=Reverse)
         return Dirs + Files
 
+    def _IsDir(self, Entry: Path) -> bool:
+        """Entry.is_dir() answered from the type _BuildEntries' scandir already
+        read, so the synchronous build never stats an entry. A dead network
+        mount (e.g. a CIFS share whose host is down) blocks every stat for
+        ~20s, which froze the whole listing for minutes."""
+        IsDir = self.EntryIsDir.get(Entry)
+        return Entry.is_dir() if IsDir is None else IsDir
+
     def _BuildEntries(self, DirPath: Path) -> list[ft.Control]:
         self.EntryTiles = {}
         self.ColumnCells = {}
@@ -1300,7 +1312,15 @@ class Browser(ft.Row):
         # next refresh, same as any other entry list change.
         self.FolderIconOverrides = LoadFolderIconOverrides()
         try:
-            Entries = list(DirPath.iterdir())
+            with os.scandir(DirPath) as Scan:
+                self.EntryIsDir = {}
+                for DirEntry in Scan:
+                    try:
+                        # Uses the listing's d_type, no stat (except for symlinks).
+                        self.EntryIsDir[DirPath / DirEntry.name] = DirEntry.is_dir()
+                    except OSError:
+                        self.EntryIsDir[DirPath / DirEntry.name] = False
+            Entries = list(self.EntryIsDir)
         except (PermissionError, FileNotFoundError):
             self.CurrentEntries = []
             return [ft.Text("Can't read this folder.", italic=True)]
@@ -1445,7 +1465,7 @@ class Browser(ft.Row):
             ),
             expand=True,
         )
-        if Entry.is_dir():
+        if self._IsDir(Entry):
             # A directory row is both a drag source (like any other entry, so
             # it can itself be moved elsewhere) and a drop target (so other
             # entries can be dropped into it) — same MoveIntoDirectory Sidebar
@@ -1544,7 +1564,7 @@ class Browser(ft.Row):
                 on_secondary_tap_down=lambda e, p=Entry: self._RequestMenu(p, e),
             ),
         )
-        if Entry.is_dir():
+        if self._IsDir(Entry):
             # Same drop-target treatment as the list view's directory rows —
             # see _BuildListRow.
             return ft.DragTarget(
@@ -1555,7 +1575,7 @@ class Browser(ft.Row):
         return GridDraggable
 
     def _LeadingFor(self, Entry: Path, Size: int = 32):
-        if Entry.is_dir():
+        if self._IsDir(Entry):
             return self._ResolveFolderIconFull(Entry, Size)
         if IsThumbnailable(Entry):
             ThumbnailPath = GetThumbnail(Entry, Size=(Size * 2, Size * 2))