Harden WITHSCORES detection and reject empty scorer names

- Detect WITHSCORES mode via translated.score_alias instead of
  scanning args for the literal token, preventing false positives
  if a field is named WITHSCORES.
- Reject score('') with a clear ValueError so the caller's intent
  is not silently lost by falling back to the default scorer.

Author: nkanu17

sql_redis/executor.py

@@ -209,8 +209,10 @@ def execute(self, sql: str, *, params: dict | None = None) -> QueryResult:
         rows = []
 
         if translated.command == "FT.SEARCH":
-            # Check if WITHSCORES was requested — changes response format
-            with_scores = "WITHSCORES" in translated.args
+            # Use the explicit score_alias signal rather than scanning args
+            # for the literal token "WITHSCORES", which could false-positive
+            # if a returned field happened to be named "WITHSCORES".
+            with_scores = translated.score_alias is not None
             # RETURN 0 suppresses document fields (like NOCONTENT);
             # with WITHSCORES the reply is [count, id, score, id, score, ...]
             no_content = self._has_return_0(translated.args)
@@ -336,7 +338,7 @@ async def execute(self, sql: str, *, params: dict | None = None) -> QueryResult:
         rows = []
 
         if translated.command == "FT.SEARCH":
-            with_scores = "WITHSCORES" in translated.args
+            with_scores = translated.score_alias is not None
             no_content = self._has_return_0(translated.args)
 
             score_alias: str | None = None

sql_redis/parser.py

@@ -476,6 +476,12 @@ def _process_select_expression_inner(
                             "score() argument must be a string scorer name "
                             f"(e.g., 'BM25', 'TFIDF'), got {scorer_val!r}."
                         )
+                    if not scorer_val:
+                        raise ValueError(
+                            "score() scorer name must not be empty. "
+                            "Use score() with no arguments for the default "
+                            "BM25 scorer, or pass a valid name like 'TFIDF'."
+                        )
                     scorer = scorer_val
                 if result.scoring is not None:
                     raise ValueError(