fix: Upload-Sanitizing, atomare Import-Reihenfolge, idempotentes UNBEKANNT-Konto

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

finance/app/services/importer.py

@@ -12,12 +12,11 @@ from app.services.categorize import apply_rules
 
 
 def _find_or_create_account(session: Session, bank: str, iban: str | None, filename: str) -> Account:
-    if iban:
-        acc = session.execute(select(Account).where(Account.iban == iban)).scalar()
-        if acc is not None:
-            return acc
-    else:
+    if not iban:
         iban = f"UNBEKANNT-{filename}"
+    acc = session.execute(select(Account).where(Account.iban == iban)).scalar()
+    if acc is not None:
+        return acc
     acc = Account(bank=bank, iban=iban, name=iban, type="giro")
     session.add(acc)
     session.flush()
@@ -89,11 +88,19 @@ def process_pdf(session: Session, path: Path) -> Statement:
     apply_rules(session, drafts)
 
     stmt.status = "draft"
+
+    # Invariant: a committed draft implies the PDF left the inbox. Move the
+    # file before committing so a failed move can never leave a committed
+    # draft with the PDF still sitting in the inbox.
+    uploads_dir = settings.uploads_dir
+    uploads_dir.mkdir(parents=True, exist_ok=True)
+    try:
+        path.replace(uploads_dir / filename)
+    except OSError:
+        session.rollback()
+        raise
+
     session.commit()
     session.refresh(stmt)
 
-    uploads_dir = settings.uploads_dir
-    uploads_dir.mkdir(parents=True, exist_ok=True)
-    path.replace(uploads_dir / filename)
-
     return stmt