Type Coercion Error in Routine endTime Calculation Bypasses Overlap Validation

[Abhishek2005-ard]

Description

There is a logic bug in backend/controllers/routineController.js inside both the createRoutine and updateRoutine functions caused by unsafe type coercion.

When the server calculates the endTime of a routine task to check for scheduling overlaps, it relies on the + operator:

const endTime = item.startTime + item.duration;

[Abhishek2005-ard]

/assign

[github-actions]

Hi @Abhishek2005-ard, please wait 6h before claiming this issue again (cooldown active).

[GeethaBurigalla]

/assign

[github-actions]

Hi @GeethaBurigalla, please wait 6h before claiming this issue again (cooldown active).

[khalidsaifullah-ks]

Hi! I am a GSSoC '26 contributor. I would love to work on this issue. Could you please assign it to me? Thank you!

[karrisanthoshigayatri]

Hi @aryandas2911,

I'd like to work on this issue under GSSoC'26.

From the issue description, I understand that the overlap validation in createRoutine and updateRoutine is affected by JavaScript's type coercion when calculating endTime using item.startTime + item.duration. If either value is a string, the + operator performs string concatenation instead of numeric addition, which can lead to incorrect overlap checks.

My approach is to:

• Ensure both startTime and duration are explicitly converted to numbers before performing the calculation.
• Apply the fix consistently in both createRoutine and updateRoutine.
• Validate inputs to prevent invalid or non-numeric values from bypassing the scheduling logic.
• Test overlapping and non-overlapping scenarios to verify the validation works correctly without affecting existing functionality.

I'll keep the implementation minimal, consistent with the current codebase, and focused on fixing the root cause.

Could you please assign this issue to me? Thank you!