fix: handle DataNotLoadedError and session load failures gracefully (…

[nirvik34]

Closes #245

Problem

When session data fails to load, the app crashes with a raw FastF1
traceback — confusing for users who don't know what
DataNotLoadedError means.

Changes

src/f1_data.py

• Added robust error handling in load_session() helper
• Catches DataNotLoadedError → session may not exist yet or still processing
• Catches ConnectionError → tells user to check network
• Catches metadata errors → prompts user to verify year/round inputs
• App exits cleanly with friendly message instead of raw traceback

main.py

• Added exit_on_failure=False flag for secondary qualifying data load
• Race replay now continues even if qualifying/DRS zone data is unavailable

Before vs After

Before:

fastf1.exceptions.DataNotLoadedError: The data you are trying to access has not been loaded yet. See Session.load

After:

[ERROR] Session data could not be loaded.
This usually means:

• The session hasn't happened yet
• There's a network connectivity issue
• The FastF1 cache is corrupted (try deleting .fastf1-cache/)

Testing

• Valid session → loads normally
• Invalid round number → friendly error shown
• Missing qualifying data → race replay still continues

[HEPNARL]

This is not a good long term solution for the problem, and could cause unexpected issues in the future. Major changes are required.

[HEPNARL]

Catching all exceptions as a generic exception and potentially ignoring them can cause problems in future. fastf1 provides list of possible thrown exception and they should be treated as needed. If there's no match the the program should exit with fail code no matter what happens.

[nirvik34]

I refactored load_session to catch specific fastf1 and requests exceptions instead of using generic ones.

[HEPNARL]

can you add some test cases or give specific calls that hit each catch clause for those that are possible to replicate? Just trying to do what the test case tells the problem is doesn't appear to be doing anything and falls as exception somewhere else.

[nirvik34]

I added some screenshots of the improved terminal errors showing testing of each case.

[nirvik34]

are thes changes fine?