3680882 - Decimal Serialization Issues for CAP application

After upgrading from an older cds version (prior to 2024 June releases) to the latest one, the following issue is visible in the CAP application:

Decimal values returned as strings:

Decimal fields (e.g., Decimal (20,2)) are now returned as strings in the service response.
Example:

"currentValue": "20.34"

Expected Behavior (Previous Version):

"currentValue": 20.34

and also

Decimal truncation (0.00 → 0)

Observed Behavior:

"currentValue": "0"

Expected Behavior:

"currentValue": "0.00"

Possible Impacts:

• Consuming systems fail validations or arithmetic operations expecting numeric values.
• Causes data mismatches and logic errors in downstream systems.
• Precision and validation logic are affected where exact decimal format is required.
• Causes downstream system validation failures for financial and calculation fields.

Business Technology Platform

BTP, decimal, CAP, cds, version, application, upgrade, validation, value, functionality , KBA , BC-XS-CDX-NJS , SAP CAP – node.js runtime , Problem