Rejects field names starting with #, ^ and /

ftl/core/fields.ftl

@@ -12,3 +12,4 @@ fields-reverse-text-direction-rtl = Reverse text direction (RTL)
 fields-size = Size:
 fields-sort-by-this-field-in-the = Sort by this field in the browser
 fields-that-field-name-is-already-used = That field name is already used.
+fields-name-first-letter-not-valid = The field name should not start with #, ^ or /.

qt/aqt/fields.py

@@ -85,6 +85,9 @@ class FieldDialog(QDialog):
         txt = getOnlyText(prompt, default=old).replace('"', "").strip()
         if not txt:
             return
+        if txt[0] in "#^/":
+            showWarning(tr(TR.FIELDS_NAME_FIRST_LETTER_NOT_VALID))
+            return
         for f in self.model["flds"]:
             if ignoreOrd is not None and f["ord"] == ignoreOrd:
                 continue