fix(trash): allow the mount's own trash when the output folder is a mount point (#543)

An output root that is exactly a mount root may hold that mount's .Trash-$uid
and .Trash/$uid, with the spec's checks intact. Any other trash inside a root
stays refused, and so does a root inside the trash. Media routes no longer
serve files in trash folders, and a review with nothing to move shows a
neutral disabled primary.

utils/diagnostics.py

@@ -37,6 +37,7 @@ from pathlib import Path
 from typing import Dict, Any
 
 from .logging_config import get_logger
+from .media_folders import in_skipped_folder
 
 try:
     from ..database.workflow_documents import DocumentReader, resolve_image_row
@@ -298,7 +299,13 @@ class GalleryDiagnostics:
                 try:
                     image_files = []
                     for ext in [".png", ".jpg", ".jpeg", ".webp"]:
-                        image_files.extend(Path(abs_path).rglob(f"*{ext}"))
+                        image_files.extend(
+                            found
+                            for found in Path(abs_path).rglob(f"*{ext}")
+                            if not in_skipped_folder(
+                                found.relative_to(abs_path).parts[:-1]
+                            )
+                        )
                     self.logger.info(f"      [IMG]  Images found: {len(image_files)}")
                 except Exception as e:
                     self.logger.error(f"      [FAIL] Error scanning: {e}")

utils/media_folders.py

@@ -26,6 +26,15 @@ def is_skipped_folder(name: str) -> bool:
     return name == PREVIEW_FOLDER or is_trash_folder(name)
 
 
+def in_trash_folder(relative: str) -> bool:
+    """Whether a root-relative file path lies in a trash folder (#543).
+
+    Takes either separator. Previews of it (``thumbnails/.Trash-1000/...``) count.
+    """
+    folders = relative.replace("\\", "/").split("/")[:-1]
+    return any(is_trash_folder(part) for part in folders)
+
+
 def in_skipped_folder(parts) -> bool:
     """Whether any of the folder names *parts* is skipped."""
     return any(is_skipped_folder(part) for part in parts)

utils/trash.py

@@ -6,7 +6,10 @@ Two rules hold for every backend:
   filesystem. Nothing is ever copied, unlinked or overwritten: a file that
   cannot be moved recoverably stays where it is, and ``TrashRefused`` says why.
 - **Never into a root.** A trash folder inside an output root would be listed
-  as images, so it is refused (``trash-in-root``).
+  as images, so it is refused (``trash-in-root``). The one exception (#543): for
+  an output root that is exactly a mount root, that mount's own ``.Trash-$uid``
+  and ``.Trash/$uid``, which every walker and media route ignores
+  (``utils.media_folders``).
 
 Linux and BSD use :class:`FreedesktopBackend`, the freedesktop.org Trash
 specification 1.0: the home trash (``$XDG_DATA_HOME/Trash``) for a file on the
@@ -184,10 +187,21 @@ def _canonical(path: str) -> str:
     return os.path.normcase(os.path.realpath(path))
 
 
-def _check_roots(trash_dir: str, roots) -> None:
+def _check_roots(trash_dir: str, roots, top: str | None = None) -> None:
+    """Refuse a trash that a root would list, or that holds a root.
+
+    *top* is the mount a per-drive *trash_dir* was built from. A root that is
+    exactly that mount may hold it, unless a link makes the trash really live
+    somewhere else (#543). Any other root holding it refuses, also beside one.
+    """
     trash_key = _canonical(trash_dir)
+    top_key = None if top is None else _canonical(top)
+    unlinked = trash_key == os.path.normcase(trash_dir)
     for root in roots:
-        if _inside(trash_key, _canonical(str(root))):
+        root_key = _canonical(str(root))
+        if _inside(root_key, trash_key):
+            raise TrashRefused(TRASH_IN_ROOT)
+        if _inside(trash_key, root_key) and not (unlinked and root_key == top_key):
             raise TrashRefused(TRASH_IN_ROOT)
 
 
@@ -267,7 +281,7 @@ class FreedesktopBackend:
             candidates.append(os.path.join(shared, str(self._uid)))
         candidates.append(os.path.join(top, f".Trash-{self._uid}"))
         for trash_dir in candidates:
-            _check_roots(trash_dir, roots)
+            _check_roots(trash_dir, roots, top)
             if self._usable(trash_dir, create=create):
                 label = f"{os.path.relpath(trash_dir, top)} on its drive"
                 return trash_dir, top, label