Fix #2762: Make CSV knowledge sources detect and load file updates

Co-Authored-By: Joe Moura <joao@crewai.com>

src/crewai/knowledge/source/base_file_knowledge_source.py

@@ -43,7 +43,15 @@ class BaseFileKnowledgeSource(BaseKnowledgeSource, ABC):
         """Post-initialization method to load content."""
         self.safe_file_paths = self._process_file_paths()
         self.validate_content()
+        self._record_file_mtimes()
         self.content = self.load_content()
+        
+    def _record_file_mtimes(self):
+        """Record modification times of all files."""
+        self._file_mtimes = {}
+        for path in self.safe_file_paths:
+            if path.exists() and path.is_file():
+                self._file_mtimes[path] = path.stat().st_mtime
 
     @abstractmethod
     def load_content(self) -> Dict[Path, str]:
@@ -107,3 +115,14 @@ class BaseFileKnowledgeSource(BaseKnowledgeSource, ABC):
             )
 
         return [self.convert_to_path(path) for path in path_list]
+        
+    def files_have_changed(self) -> bool:
+        """Check if any of the files have been modified since they were last loaded."""
+        for path in self.safe_file_paths:
+            if not path.exists() or not path.is_file():
+                continue
+            current_mtime = path.stat().st_mtime
+            if path not in self._file_mtimes or current_mtime > self._file_mtimes[path]:
+                self._logger.log("info", f"File {path} has been modified. Reloading data.")
+                return True
+        return False