fix: handle String values from Redis FT.INFO in count() method (#639)

Fixes ClassCastException when count() method receives "num_docs" as a String
from Redis FT.INFO command instead of a numeric type. The method now properly
handles both String and Number types by parsing or converting them to long.

- Parse String values using Long.parseLong()
- Convert Number values using longValue()
- Return 0 for null or unexpected types
- Added test case to verify fix in EntityStreamsIssuesTest

Closes #639

Author: bsbodden

redis-om-spring/src/main/java/com/redis/om/spring/search/stream/SearchStreamImpl.java

@@ -496,7 +496,17 @@ public long count() {
       return searchResult.getTotalResults();
     } else {
       var info = search.getInfo();
-      return (long) info.get("num_docs");
+      Object numDocsValue = info.get("num_docs");
+      
+      // Handle different return types from Redis (fixes issue #639)
+      if (numDocsValue instanceof String) {
+        return Long.parseLong((String) numDocsValue);
+      } else if (numDocsValue instanceof Number) {
+        return ((Number) numDocsValue).longValue();
+      } else {
+        // Fallback to 0 if the value is null or unexpected type
+        return 0L;
+      }
     }
   }
 

tests/src/test/java/com/redis/om/spring/search/stream/EntityStreamsIssuesTest.java

@@ -609,4 +609,37 @@ void testEqAgainstContentWithForwardSlash() {
     doc2Repository.deleteAll(List.of(doc1, doc2));
   }
 
+  @Test
+  void testIssue639_CountMethodHandlesStringNumDocs() {
+    // Issue #639: ClassCastException in count() when num_docs is returned as String
+    // This test ensures that count() properly handles String values from Redis FT.INFO
+    
+    // Clear existing data
+    docRepository.deleteAll();
+    
+    // Create exactly 21 documents (matching the issue report)
+    List<Doc> docs = new ArrayList<>();
+    for (int i = 1; i <= 21; i++) {
+      Doc doc = Doc.of("first" + i, "second" + i);
+      doc.setId("doc" + i);
+      docs.add(doc);
+    }
+    docRepository.saveAll(docs);
+    
+    // Test count with no filter - this triggers the info.get("num_docs") path
+    long count = entityStream.of(Doc.class).count();
+    assertThat(count).isEqualTo(21);
+    
+    // Test count with filter - uses query-based count
+    long filteredCount = entityStream.of(Doc.class)
+        .filter(Doc$.FIRST.startsWith("first"))
+        .count();
+    assertThat(filteredCount).isEqualTo(21);
+    
+    // Clean up
+    docRepository.deleteAll();
+    long finalCount = entityStream.of(Doc.class).count();
+    assertThat(finalCount).isEqualTo(0);
+  }
+
 }