don't allow empty files in media folder

anki/consts.py

@@ -42,7 +42,7 @@ MODEL_STD = 0
 MODEL_CLOZE = 1
 
 # deck schema & syncing vars
-SCHEMA_VERSION = 8
+SCHEMA_VERSION = 9
 SYNC_ZIP_SIZE = int(2.5*1024*1024)
 SYNC_URL = os.environ.get("SYNC_URL") or "https://beta.ankiweb.net/sync/"
 SYNC_VER = 3

anki/media.py

@@ -394,6 +394,10 @@ create table log (fname text primary key, type int);
                 continue
             if f.lower() == "thumbs.db":
                 continue
+            # empty files are invalid; clean them up and continue
+            if not os.path.getsize(f):
+                os.unlink(f)
+                continue
             # newly added?
             if f not in self.cache:
                 added.append(f)

anki/storage.py

@@ -117,6 +117,21 @@ def _upgrade(col, ver):
         col.db.execute(
             "update cards set due = due / 1000 where due > 4294967296")
         col.db.execute("update col set ver = 8")
+    if ver < 9:
+        # adding an empty file to a zip makes python's zip code think it's a
+        # folder, so remove any empty files
+        changed = False
+        for f in os.listdir(col.media.dir()):
+            if not os.path.getsize(f):
+                os.unlink(f)
+                col.media.db.execute(
+                    "delete from log where fname = ?", f)
+                col.media.db.execute(
+                    "delete from media where fname = ?", f)
+                changed = True
+        if changed:
+            col.media.db.commit()
+        col.db.execute("update col set ver = 9")
 
 def _upgradeClozeModel(col, m):
     m['type'] = MODEL_CLOZE