[Bug] UnboundLocalError When `modelname` or `casename` is `None` in DataFileRoute Endpoints

[tejassinghbhati]

Summary

Several API endpoints in DataFileRoute.py (including /cleanUp, /resultsExists, /createCaseRun, /updateViews, and others) check conditions like:

if modelname != None or casename != None:

but fail to handle the case where the value is None.

When modelname or casename is None (for example, if the frontend sends a malformed request or the session is empty), the code skips the if block where the response variable is defined and drops directly into:

return jsonify(response), 200

Because response was never assigned a value, the server crashes with a fatal UnboundLocalError.

Expected behavior

If a required parameter like casename or modelname is None or omitted from the JSON payload, the API should handle it gracefully and return a structured error such as:

HTTP 400 Bad Request
{
  "message": "Missing required parameter: modelname",
  "status_code": "error"
}

This prevents a server crash and provides meaningful feedback to the client.

Reproduction steps

1. Start the Flask application:

python app.py

2. Open a new PowerShell terminal and send a POST request with null data:

Invoke-RestMethod `
  -Uri "http://127.0.0.1:5002/cleanUp" `
  -Method POST `
  -Headers @{"Content-Type"="application/json"} `
  -Body '{"modelname": null}'

3. Observe the response:

HTTP 500 Internal Server Error

4. Check the terminal where python app.py is running.

You will see an unhandled traceback ending with:

UnboundLocalError: local variable 'response' referenced before assignment

(or on Python 3.11+)

UnboundLocalError: cannot access local variable 'response' where it is not associated with a value

---

Root Cause

The route logic only defines response inside a conditional block but still attempts to return it even when the condition fails.

Example pattern found in multiple endpoints:

if modelname != None:
    response = {...}

return jsonify(response), 200

When modelname is None, response is never created.

---

Root Cause

The route logic only defines response inside a conditional block but still attempts to return it even when the condition fails.

Example pattern found in multiple endpoints:

if modelname != None:
    response = {...}

return jsonify(response), 200

When modelname is None, response is never created.

Suggested Fix

Validate input parameters at the beginning of each endpoint and return a 400 Bad Request if they are missing or None.

Example:

modelname = request.json.get("modelname")

if modelname is None:
    return jsonify({
        "message": "Missing required parameter: modelname",
        "status_code": "error"
    }), 400

Alternatively, initialize response before conditional logic or restructure the control flow to ensure it is always defined.

Environment

Environment

Field	Value
OS	Windows / Linux / macOS
Python	Python 3.11+
Branch	main (latest commit)
Affected File	API/Routes/DataFile/DataFileRoute.py

---

Impact

• Causes 500 server crashes from malformed or incomplete client requests
• Affects multiple endpoints in DataFileRoute.py
• Prevents proper API error handling and client-side debugging

Logs or screenshots