using E as a variable behaves different from 1.6 release

[dcaillia]

using E as a variable behaves different from 1.6 release

[uklimaschewski]

Yes, constants are now constants and can't be overwritten.
I think that behavior is correct and should be kept, but I see your point.
I am thinking about a configuration option, overwriteConstantsAllowed or similar, that would allow to make a constant a variable. Effectively meaning, if you set a value which is a constant, the constant will be removed and a variable with that name and value will be set. In that way, also the getUsedVariables() method will give correct results. (Which it does not now in your case).

Better in your case I think would be to configure a new default set of constants. Then use that configuration with the expression:

  @Test
  void testRemoveConstant() throws EvaluationException, ParseException {
    Map<String, EvaluationValue> constants =
        new HashMap<>(ExpressionConfiguration.StandardConstants);
    constants.remove("E");

    ExpressionConfiguration configuration =
        ExpressionConfiguration.builder().defaultConstants(constants).build();

    Expression expression = new Expression("E", configuration);

    assertThat(expression.with("e", 0).evaluate().getStringValue()).isEqualTo("0");
  }