Simple gradle build file build error - build

Question

I am trying out several gradle basics.
Here is how my gradle file "build.gradle" looked:
task hello
{
doLast
{
println 'Hello World!'
}
}
This causes the following error:
D:\DevAreas\learn-gradle>gradle -q hello
FAILURE: Build failed with an exception.
* Where:
Build file 'D:\DevAreas\learn-gradle\build.gradle' line: 2
* What went wrong:
Could not compile build file 'D:\DevAreas\learn-gradle\build.gradle'.
> startup failed:
build file 'D:\DevAreas\learn-gradle\build.gradle': 2: Ambiguous expression could be a parameterle
ss closure expression, an isolated open code block, or it may continue a previous statement;
solution: Add an explicit parameter list, e.g. {it -> ...}, or force it to be treated as an open
block by giving it a label, e.g. L:{...}, and also either remove the previous newline, or add an exp
licit semicolon ';' # line 2, column 1.
{
^
1 error
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more l
og output.
If I make a minor modification to the build file like so
[Please NOTE that I have moved the parenthesis from second line to
first line]
task hello{
doLast
{
println 'Hello World!'
}
}
I see the output
Hello World!
with out issues.
Is parenthesis such a big problem in gradle? What was I doing so wrong by placing the parenthesis in the second line?

Answer 1

As with other languages that use semicolon inference, the newline makes a difference in Groovy. The first snippet gets parsed as task hello; { ... }, which is ambiguous (can't decide if the second statement is a block or a closure) and hence invalid Groovy syntax. It's not what you want anyway; you want the closure to be associated with the hello task. To avoid such surprises, I recommend to follow the Java braces style.