CompileException on seemingly valid MVEL. Adding two extra semi-colons after closing else if block curly brace resolves exception; one is not enough.

[ScottCUSA]

MVEL throws a CompileException when passing valid MVEL to org.mvel2.MVEL.evalToString.

port = 'ae1'; 
if (port.contains('-')) {
    port = port.substring(port.indexOf('-') + 1);
} else if (port.startsWith('ae')) {
    port = port.replace('ae', 'lag-');
} 
port = port.toLowerCase();
return port;

This is the exception:

org.mvel2.CompileException: [Error: unexpected token or unknown identifier:port.toLowerCase()]
[Near : {... sWith('ae')) {port = port.replace('ae', 'lag-');} port = port.toLowerCase(); ....}]
                                                               ^
[Line: 1, Column: 156]
	at org.mvel2.MVELInterpretedRuntime.parseAndExecuteInterpreted(MVELInterpretedRuntime.java:149) ~[jaxws-api-2.3.1.jar:?]
	at org.mvel2.MVELInterpretedRuntime.parse(MVELInterpretedRuntime.java:58) ~[jaxws-api-2.3.1.jar:?]
	at org.mvel2.MVEL.eval(MVEL.java:170) ~[jaxws-api-2.3.1.jar:?]
	at org.mvel2.MVEL.evalToString(MVEL.java:349) ~[jaxws-api-2.3.1.jar:?]]
        ...

If I add two semi-colons to the end of the if block immediately proceeding the "unexpected token" it works without issue.

port = 'ae1'; 
if (port.contains('-')) {
    port = port.substring(port.indexOf('-') + 1);
} else if (port.startsWith('ae')) {
    port = port.replace('ae', 'lag-');
} ;; /* THESE TWO SEMI-COLONS RESOLVE COMPILE EXCEPTION */
port = port.toLowerCase();
return port;

result = lag-1

[ScottCUSA]

I attempted to determine what was going on by debugging the AbstractParser while running on the example code. I don't know enough about how it's supposed to work to determine how to fix it.

From what I can tell it looks like there's a "null" value on the parser stack when it should be empty prior to evaluating the expression port = port.toUpperCase()

When adding the two extra semi-colons it looks like the parser stack is cleared prior to it starting to parse port = port.toLowerCase();

https://github.com/mvel/mvel/blob/85125e1af5f3ec32990b1768b8656bfcf450b489/src/main/java/org/mvel2/compiler/AbstractParser.java