Move whitespace check for tags from to sqlwriter

Instead of not parsing a tag containing whitespace, check for spaces
when writing sql and if there are any, explicitly match nothing.

rslib/src/search/parser.rs

@@ -281,7 +281,7 @@ fn search_node_for_text_with_argument<'a>(
         "edited" => SearchNode::EditedInDays(val.parse()?),
         "deck" => SearchNode::Deck(unescape_quotes(val)),
         "note" => SearchNode::NoteType(unescape_to_re(val)?),
-        "tag" => SearchNode::Tag(parse_tag(val)?),
+        "tag" => SearchNode::Tag(unescape_to_enforced_re(val, r"\S")?),
         "mid" => SearchNode::NoteTypeID(val.parse()?),
         "nid" => SearchNode::NoteIDs(check_id_list(val)?),
         "cid" => SearchNode::CardIDs(check_id_list(val)?),
@@ -300,15 +300,6 @@ fn search_node_for_text_with_argument<'a>(
     })
 }
 
-/// Ensure the string doesn't contain whitespace and unescape.
-fn parse_tag(s: &str) -> ParseResult<String> {
-    if s.as_bytes().iter().any(u8::is_ascii_whitespace) {
-        Err(ParseError {})
-    } else {
-        unescape_to_enforced_re(s, r"\S")
-    }
-}
-
 /// ensure a list of ids contains only numbers and commas, returning unchanged if true
 /// used by nid: and cid:
 fn check_id_list(s: &str) -> ParseResult<&str> {

rslib/src/search/sqlwriter.rs

@@ -189,6 +189,9 @@ impl SqlWriter<'_> {
     }
 
     fn write_tag(&mut self, s: &String) -> Result<()> {
+        if s.contains(" ") {
+            write!(self.sql, "false").unwrap();
+        } else {
         match s.as_str() {
             "none" => write!(self.sql, "n.tags = ''").unwrap(),
             r"\S*" => write!(self.sql, "true").unwrap(),
@@ -197,6 +200,7 @@ impl SqlWriter<'_> {
                 self.args.push(format!("(?i).* {} .*", s));
             }
         }
+        }
 
         Ok(())
     }