Fix: Handle None values in LLM-generated JSON

student/code_generator.py

@@ -211,17 +211,24 @@ Generate ONLY the JSON output, no other text. Ensure all code is complete and fu
 
         json_match = re.search(r"```json\s*(\{.*?\})\s*```", content, re.DOTALL)
         if json_match:
-            return json.loads(json_match.group(1))
+            result = json.loads(json_match.group(1))
+            # Validate that all values are strings
+            return {k: v for k, v in result.items() if v is not None}
 
         # Try to parse the whole content as JSON
         try:
-            return json.loads(content)
+            result = json.loads(content)
+            # Validate that all values are strings
+            return {k: v for k, v in result.items() if v is not None}
         except json.JSONDecodeError:
             # Try to find any JSON object
             json_match = re.search(r"\{.*\}", content, re.DOTALL)
             if json_match:
-                return json.loads(json_match.group(0))
+                result = json.loads(json_match.group(0))
+                # Validate that all values are strings
+                return {k: v for k, v in result.items() if v is not None}
 
+        logger.error(f"Could not extract JSON from LLM response: {content[:200]}")
         raise ValueError("Could not extract JSON from LLM response")
 
     def _get_fallback_template(self) -> dict[str, str]:
@@ -271,6 +278,16 @@ MIT License
         output_dir.mkdir(parents=True, exist_ok=True)
 
         for filename, content in files.items():
+            # Skip None or empty content
+            if content is None:
+                logger.warning(f"Skipping {filename} - content is None")
+                continue
+            
+            # Ensure content is a string
+            if not isinstance(content, str):
+                logger.warning(f"Converting {filename} content to string")
+                content = str(content)
+            
             file_path = output_dir / filename
             file_path.write_text(content, encoding="utf-8")
             logger.debug(f"Saved {filename} ({len(content)} bytes)")