string() function wraps a string into a string value

[saig0]

Describe the bug
If I invoke the string() function with a string argument, the function wraps the string into another string. As a result, the string value is escaped.

This behavior is different compared to previous versions of the FEEL engine (i.e. a regression).

The wrapped string value is complicated to handle because I need to unwrap it before using it.

To Reproduce
Steps to reproduce the behavior:

1. Evaluate the expression

string("foo")

2. Verify that the result is a string wrapped inside a string

"\"foo\""

Expected behavior
If I invoke the string() function with a string value, it should return the string value as it is (i.e. no wrapping, no escaping).

string("foo")        => "foo"

Related DMN-TCK test case 0079-feel-string-function.

Environment

• FEEL engine version: 1.17.0
• Affects:
  • Camunda Automation Platform 7: [7.x]
  • Zeebe broker: 8.3.0