fix: finish support of type assertions which was incomplete (#657)

* fix: finish support of type assertions which was incomplete

TypeAssert was optimistically returning ok without verifying that
value could be converted to the required interface (in case of
type assert of an interface type), or not checking the type in
all conditions. There is now a working implements method for itype.

Fixes #640.

* style: appease lint

* fix: remove useless code block

* doc: improve comments

* avoid test conflict
This commit is contained in:
Marc Vertes
2020-06-10 11:21:16 +02:00
committed by GitHub
parent def57d57c2
commit c1f5005b2a
5 changed files with 176 additions and 49 deletions

View File

@@ -122,34 +122,38 @@ func runCfg(n *node, f *frame) {
}
func typeAssertStatus(n *node) {
c0, c1 := n.child[0], n.child[1]
c0, c1 := n.child[0], n.child[1] // cO contains the input value, c1 the type to assert
value := genValue(c0) // input value
value1 := genValue(n.anc.child[1]) // returned status
typ := c1.typ.rtype // type to assert
next := getExec(n.tnext)
switch {
case c0.typ.cat == valueT:
case isInterfaceSrc(c1.typ):
typ := c1.typ
n.exec = func(f *frame) bltn {
v := value(f)
if !v.IsValid() || v.IsNil() {
value1(f).SetBool(false)
}
value1(f).SetBool(v.Type().Implements(typ))
v, ok := value(f).Interface().(valueInterface)
value1(f).SetBool(ok && v.node.typ.implements(typ))
return next
}
case c1.typ.cat == interfaceT:
case isInterface(c1.typ):
rtype := c1.typ.rtype
n.exec = func(f *frame) bltn {
_, ok := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
value1(f).SetBool(ok)
v := value(f)
value1(f).SetBool(v.IsValid() && v.Type().Implements(rtype))
return next
}
case c0.typ.cat == valueT:
rtype := c1.typ.rtype
n.exec = func(f *frame) bltn {
v := value(f)
value1(f).SetBool(v.IsValid() && v.Type() == rtype)
return next
}
default:
typID := c1.typ.id()
n.exec = func(f *frame) bltn {
_, ok := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
value1(f).SetBool(ok)
v, ok := value(f).Interface().(valueInterface)
value1(f).SetBool(ok && v.node.typ.id() == typID)
return next
}
}
@@ -162,24 +166,35 @@ func typeAssert(n *node) {
next := getExec(n.tnext)
switch {
case c0.typ.cat == valueT:
case isInterfaceSrc(c1.typ):
typ := n.child[1].typ
typID := n.child[1].typ.id()
n.exec = func(f *frame) bltn {
v := value(f)
dest(f).Set(v.Elem())
vi, ok := v.Interface().(valueInterface)
if !ok {
panic(n.cfgErrorf("interface conversion: nil is not %v", typID))
}
if !vi.node.typ.implements(typ) {
panic(n.cfgErrorf("interface conversion: %v is not %v", vi.node.typ.id(), typID))
}
dest(f).Set(v)
return next
}
case c1.typ.cat == interfaceT:
case isInterface(c1.typ):
rtype := n.child[1].typ.rtype
n.exec = func(f *frame) bltn {
v := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
dest(f).Set(reflect.ValueOf(valueInterface{v.node, v.value}))
dest(f).Set(value(f).Convert(rtype))
return next
}
case c0.typ.cat == valueT:
n.exec = func(f *frame) bltn {
dest(f).Set(value(f).Elem())
return next
}
default:
n.exec = func(f *frame) bltn {
v := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
dest(f).Set(v.value)
dest(f).Set(value(f).Interface().(valueInterface).value)
return next
}
}
@@ -189,30 +204,58 @@ func typeAssert2(n *node) {
value := genValue(n.child[0]) // input value
value0 := genValue(n.anc.child[0]) // returned result
value1 := genValue(n.anc.child[1]) // returned status
typ := n.child[1].typ // type to assert or convert to
typID := typ.id()
next := getExec(n.tnext)
switch {
case n.child[0].typ.cat == valueT:
n.exec = func(f *frame) bltn {
if value(f).IsValid() && !value(f).IsNil() {
value0(f).Set(value(f).Elem())
}
value1(f).SetBool(true)
return next
}
case n.child[1].typ.cat == interfaceT:
case isInterfaceSrc(typ):
n.exec = func(f *frame) bltn {
v, ok := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
value0(f).Set(reflect.ValueOf(valueInterface{v.node, v.value}))
if ok && v.node.typ.id() == typID {
value0(f).Set(value(f))
} else {
ok = false
}
value1(f).SetBool(ok)
return next
}
case isInterface(typ):
rtype := typ.rtype
n.exec = func(f *frame) bltn {
v := value(f)
ok := v.IsValid() && v.Type().Implements(rtype)
if ok {
value0(f).Set(v.Convert(rtype))
}
value1(f).SetBool(ok)
return next
}
case n.child[0].typ.cat == valueT:
rtype := n.child[1].typ.rtype
n.exec = func(f *frame) bltn {
v := value(f)
ok := v.IsValid() && !value(f).IsNil()
if ok {
if e := v.Elem(); e.Type() == rtype {
value0(f).Set(e)
} else {
ok = false
}
}
value1(f).SetBool(ok)
return next
}
default:
n.exec = func(f *frame) bltn {
v, ok := value(f).Interface().(valueInterface)
// TODO: verify that value(f) implements asserted type.
value0(f).Set(v.value)
if ok {
if v.node.typ.id() == typID {
value0(f).Set(v.value)
} else {
ok = false
}
}
value1(f).SetBool(ok)
return next
}