[GROOVY-990] Closure access to outer block variables - inconsistant behavior

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0-JSR-5
• Component/s: command line processing
• Assignee: Jochen Theodorou
• Reporter: nurul choudhury
• Created: 25/Jul/05 22:28
• Updated: 19/Jan/06 19:18
• Resolved: 19/Jan/06 19:18

Description

Closure using a variable outside its enclosing block has inconsistant behavior. A series of tests demonstrate the issue. In most cases if the closure is defined in a function/method works fine, but behaves incorrectly in script code (in the invisible main ). The test to demonstrate the problem is as follows:

println "Tests for groovy closure's use of 'outer scope variable'"
println "Sone strange behavior"
println "Some are a little unexpected but correct - but fails the 'least unexpected' test"

def test0() {
def list = []
for(i in ["red","green","blue"]) {

list <<

{ println i }
}
i = "Strange"
println println "Test0 logical – although somewhat unexpected - prints Strange ... \n-------"

// execute each of the 3 closures in 'list'
for( x in list) { x() }
println()
}

def test1() {
def list = []
for(i in ["red","green","blue"]) {
def v = i
list << { println v }
}
println "Test1 Fix test0 to give the desired behavior\n-------"

// execute each of the 3 closures in 'list'
for( x in list) { x() }
println()
}

// An alternative method of achieving the expected behavior
def test2() {
def list = []
for(i in ["red","green","blue"]) {
list << { println it }.curry
}
println "Test2 OK (another way to fix the problem using curry)\n-------"

// execute each of the 3 closures in 'list'
for( x in list) { x() }
println()
}

//
def test3() {
def lis = []
["red","green","blue"].each { v ->
lis << { println v }
}


println "Test3 OK\n-------"
for( x in lis ) { x() }
println()
}

//
def test3A() {
def lis = []
["red","green","blue"].each { v ->
def X = v
lis << { println X }
}


println "Test3A OK – very similar to test3\n-------"
for( x in lis ) { x() }
println()
}


// Execute the tests
test0()
test1()
test2()
test3()
test3A()

// This is code outside of a function
// this does not work right

// Test4
def list = []
for(i in ["red","green","blue"]) {
def v = i
list << { println v }
}
println "Test4, Should have given red blue green \n-------"
for( x in list) { x() }
println()

// Test 5
def lis = []
["red","green","blue"].each { i ->

lis << { println i }

}
println "Test5, does give red blue green \n-------"
for( x in lis)

{ x() }
println()

// Test 5A
def lisx = []
["red","green","blue"].each { v ->
def X = v
lisx << { println X }
}
println "Test5A, is almost identical to test3A, but behaves differently \n-------"
for( x in lisx) { x() }

println()

// Test 6
def li = []
println "Test6, fails again \n-------"
["red","green","blue"].each { s ->
def v1 = s
li <<

{ println v1 }

}

for( x in li)

{ x() }

println()

Issue Links

• is depended upon by: GROOVY-754 scoping