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https://issues.apache.org/jira/browse/GROOVY-12619?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Scott Murphy Heiberg updated GROOVY-12619:
------------------------------------------
Description:
{code:groovy}
class Box { int v = 1 }
class C {
int calls = 0
Box box = new Box()
Box obj() { calls++; box }
def m() { obj().v += 2; [calls, box.v] }
def n() { obj().v++; [calls, box.v] }
}
assert new C().m() == [1, 3]
assert new C().n() == [1, 2]
{code}
Actual: m() returns [2, 3] and n() returns [2, 2]. The receiver obj() is called
once for the read of the property and again for the write. The same happens in
dynamic Groovy, under @TypeChecked and under @CompileStatic. It also happens
for prefix and postfix increment and decrement, attribute access ({{obj().@f +=
2}}), safe navigation ({{obj()?.v += 2}}), chains with a side-effecting getter,
static properties reached through an instance, and extension properties such as
File text. Under @CompileStatic, {{obj().d++}} on a BigDecimal property calls
obj() three times.
Expected: the receiver is evaluated once, before the right-hand side, and
reused for the read and the write. Subscripts already behave this way
(GROOVY-12098).
Cause: the code generator evaluated the property expression once as an rvalue
and once as the assignment target. The static compiler's rewrites to x.p =
x.p.op(y) and to the extension setter reused the receiver expression on both
sides. The elvis assignment form is GROOVY-12515.
Seen in 4.0.33, 5.0.8 and 6.0.0.
PR: https://github.com/apache/groovy/pull/3145
was:
{code:groovy}
class Box { int v = 1 }
class C {
int calls = 0
Box box = new Box()
Box obj() { calls++; box }
def m() { obj().v += 2; [calls, box.v] }
def n() { obj().v++; [calls, box.v] }
}
assert new C().m() == [1, 3]
assert new C().n() == [1, 2]
{code}
Actual: m() returns [2, 3] and n() returns [2, 2]. The receiver obj() is called
once for the read of the property and again for the write. The same happens in
dynamic Groovy, under @TypeChecked and under @CompileStatic. It also happens
for prefix and postfix increment and decrement, attribute access ({{obj().@f +=
2}}), safe navigation ({{obj()?.v += 2}}), chains with a side-effecting getter,
static properties reached through an instance, and extension properties such as
File text. Under @CompileStatic, {{obj().d++}} on a BigDecimal property calls
obj() three times.
Expected: the receiver is evaluated once, before the right-hand side, and
reused for the read and the write. Subscripts already behave this way
(GROOVY-12098).
Cause: the code generator evaluated the property expression once as an rvalue
and once as the assignment target. The static compiler's rewrites to x.p =
x.p.op(y) and to the extension setter reused the receiver expression on both
sides. The elvis assignment form is GROOVY-12515.
Seen in 4.0.33, 5.0.8 and 6.0.0.
> Compound assignment and increment on a property evaluate the receiver
> expression twice
> --------------------------------------------------------------------------------------
>
> Key: GROOVY-12619
> URL: https://issues.apache.org/jira/browse/GROOVY-12619
> Project: Groovy
> Issue Type: Bug
> Affects Versions: 4.0.33, 5.0.8, 6.0.0
> Reporter: Scott Murphy Heiberg
> Priority: Major
>
> {code:groovy}
> class Box { int v = 1 }
> class C {
> int calls = 0
> Box box = new Box()
> Box obj() { calls++; box }
> def m() { obj().v += 2; [calls, box.v] }
> def n() { obj().v++; [calls, box.v] }
> }
> assert new C().m() == [1, 3]
> assert new C().n() == [1, 2]
> {code}
> Actual: m() returns [2, 3] and n() returns [2, 2]. The receiver obj() is
> called once for the read of the property and again for the write. The same
> happens in dynamic Groovy, under @TypeChecked and under @CompileStatic. It
> also happens for prefix and postfix increment and decrement, attribute access
> ({{obj().@f += 2}}), safe navigation ({{obj()?.v += 2}}), chains with a
> side-effecting getter, static properties reached through an instance, and
> extension properties such as File text. Under @CompileStatic, {{obj().d++}}
> on a BigDecimal property calls obj() three times.
> Expected: the receiver is evaluated once, before the right-hand side, and
> reused for the read and the write. Subscripts already behave this way
> (GROOVY-12098).
> Cause: the code generator evaluated the property expression once as an rvalue
> and once as the assignment target. The static compiler's rewrites to x.p =
> x.p.op(y) and to the extension setter reused the receiver expression on both
> sides. The elvis assignment form is GROOVY-12515.
> Seen in 4.0.33, 5.0.8 and 6.0.0.
> PR: https://github.com/apache/groovy/pull/3145
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