Fix NaN handling in pct function in db-health-alerts

[pavankumar-vh]

Overview

Fix NaN handling in the pct function in common/src/util/db-health-alerts.ts.

Bug Description

The function didn't validate that part and whole are finite numbers. If either was NaN or Infinity, Math.round((part / whole) * 100) would return NaN.

Fix

Added Number.isFinite() checks to return 0 for invalid numbers.

Testing

No existing tests for this function, but the fix prevents incorrect behavior with invalid inputs.

Files Changed

• common/src/util/db-health-alerts.ts - Added NaN validation

Scope

This change only touches common/ which is an approved contribution area per the Contributing Guide.

[codebuff-team]

Good catch. The original whole > 0 ? ... : 0 guard already handled whole being NaN/negative/Infinity, but it didn't protect against part being NaN, which would still propagate through Math.round((part / whole) * 100) and return NaN. Wrapping both operands in Number.isFinite() closes that gap cleanly.

A couple of minor notes for the private port:

• The whole <= 0 check duplicates part of the old whole > 0 condition; fine as written, but you could simplify to if (!Number.isFinite(part) || !Number.isFinite(whole) || whole <= 0) return 0 (which is what you have) — no change needed, just flagging it's slightly redundant with the finite check for edge cases like whole = -Infinity.
• Since this is a pure, easily-testable helper, it'd strengthen the PR to add a couple of unit tests (NaN part, NaN whole, whole = 0, whole = Infinity) even though none exist yet for this function — that's usually expected for logic like this and would make the fix self-evidently correct to a reviewer without needing to trace the call sites.

Scope is correct (common/ only), diff is minimal and targeted. Worth porting as-is even without tests, but adding them would make this a stronger PR.