fix storage issues

dynamodb/expression.odin

@@ -420,39 +420,34 @@ parse_expression_attribute_values :: proc(request_body: []byte) -> (map[string]A
 	return result, true
 }
 
-// NOTE: changed from Maybe(string) -> (string, bool) so callers can use or_return.
+// ============================================================================
+// FIX: Use JSON object lookup instead of fragile string scanning.
+// This handles whitespace, field ordering, and escape sequences correctly.
+// ============================================================================
 parse_key_condition_expression_string :: proc(request_body: []byte) -> (expr: string, ok: bool) {
-	body_str := string(request_body)
+	data, parse_err := json.parse(request_body, allocator = context.temp_allocator)
+	if parse_err != nil {
+		return
+	}
+	defer json.destroy_value(data)
 
-	marker :: "\"KeyConditionExpression\""
-	start_idx := strings.index(body_str, marker)
-	if start_idx < 0 {
+	root, root_ok := data.(json.Object)
+	if !root_ok {
 		return
 	}
 
-	after_marker := body_str[start_idx + len(marker):]
-	colon_idx := strings.index(after_marker, ":")
-	if colon_idx < 0 {
+	kce_val, found := root["KeyConditionExpression"]
+	if !found {
 		return
 	}
 
-	rest := after_marker[colon_idx + 1:]
-	quote_start := strings.index(rest, "\"")
-	if quote_start < 0 {
+	kce_str, str_ok := kce_val.(json.String)
+	if !str_ok {
 		return
 	}
 
-	value_start := quote_start + 1
-	pos := value_start
-	for pos < len(rest) {
-		if rest[pos] == '"' && (pos == 0 || rest[pos - 1] != '\\') {
-			expr = rest[value_start:pos]
-			ok = true
-			return
-		}
-		pos += 1
-	}
-
+	expr = string(kce_str)
+	ok = true
 	return
 }