When using a variable whose value ends with a colon, that colon is removed when the variable is evaluated.

For example, I have a property file.

root=C\:

I want to use that variable to configure my logging. Example is abbreviated to highlight the usage.

<configuration>
    <property resource="my.properties"/>
    <appender>
        <file>${root}/out.log</file>
    </appender>
</configuration>

This produces the following log output in the default logs.

Will use the pattern C/out.log for the active file

Test case to prove the issue. Using NodeToStringTransformerTest as a base.

@Before
public void setUp() {
  // existing setup
  propertyContainer0.putProperty("root", "C:");
}

@Test
public void trailingColon() throws ScanException {
  String input = "${root}";
  Node node = makeNode(input);
  NodeToStringTransformer nodeToStringTransformer = new NodeToStringTransformer(node, propertyContainer0);
  assertEquals("C:", nodeToStringTransformer.transform());
}

Test failure output.

expected:<C[:]> but was:<C[]>

The workaround is easy enough: don't let properties end in a colon. Looks bad, but works.

root=C\:/

<configuration>
    <property resource="fix.properties"/>
    <appender>
        <file>${root}out.log</file>
    </appender>
</configuration>

However, this isn't always possible. My application has a ${root} property that is assumed to be the drive/network path only, and all application paths include a leading directory slash. I can create a separate property, but having two different properties that look similar but are used in two different places is bad for maintenance.