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Merged
merged 5 commits into from
Mar 29, 2022
Merged

avm1: Fix Object < Object comparison #6548

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617e737
avm1: {} < {} returns false
Herschel Mar 27, 2022
0107ca8
tests: Unignore avm1 string_coercion test
Herschel Mar 27, 2022
1b63e42
avm1: Return Value from `abstract_lt`
Herschel Mar 27, 2022
40234e8
tests: Add Object < Object tests to lessthan2 tests
Herschel Mar 27, 2022
2054d65
tests: Add test for String(function) to string_coercion
Herschel Mar 27, 2022
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8 changes: 2 additions & 6 deletions core/src/avm1/activation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1473,9 +1473,7 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
// ECMA-262 s. 11.8.1
let a = self.context.avm1.pop();
let b = self.context.avm1.pop();
let result = b
.abstract_lt(a, self)?
.map_or(Value::Undefined, Value::from);
let result = b.abstract_lt(a, self)?;
self.context.avm1.push(result);
Ok(FrameControl::Continue)
}
Expand All @@ -1484,9 +1482,7 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
// ECMA-262 s. 11.8.2
let a = self.context.avm1.pop();
let b = self.context.avm1.pop();
let result = a
.abstract_lt(b, self)?
.map_or(Value::Undefined, Value::from);
let result = a.abstract_lt(b, self)?;
self.context.avm1.push(result);
Ok(FrameControl::Continue)
}
Expand Down
69 changes: 46 additions & 23 deletions core/src/avm1/value.rs
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Expand Up @@ -224,7 +224,9 @@ impl<'gc> Value<'gc> {
activation: &mut Activation<'_, 'gc, '_>,
) -> Result<Value<'gc>, Error<'gc>> {
Ok(match self {
Value::Object(object) => object.call_method("valueOf".into(), &[], activation)?,
Value::Object(object) if object.as_display_object().is_none() => {
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@relrelb relrelb Mar 28, 2022 •
edited
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Not directly related to this PR, but I think StageObject should be a separate enum member of Value rather than a "subclass" of Value::Object, since I have seen this special case exclusion too many times. This probably means that StageObject won't be able to implement TObject anymore, so it's not trivial at all, but I still have a feeling that StageObject and Object are more different than they have in common. Maybe this worth re-thinking as part of #5492.

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I had the same thought while writing this PR. This would fit nicely in with #5492.

object.call_method("valueOf".into(), &[], activation)?
}
val => val.to_owned(),
})
}
Expand Down Expand Up @@ -271,20 +273,35 @@ impl<'gc> Value<'gc> {
&self,
other: Value<'gc>,
activation: &mut Activation<'_, 'gc, '_>,
) -> Result<Option<bool>, Error<'gc>> {
) -> Result<Value<'gc>, Error<'gc>> {
// If either parameter's `valueOf` results in a non-movieclip object, immediately return false.
// This is the common case for objects because `Object.prototype.valueOf` returns the same object.
// For example, `{} < {}` is false.
let prim_self = self.to_primitive_num(activation)?;
if matches!(prim_self, Value::Object(o) if o.as_display_object().is_none()) {
return Ok(false.into());
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Seems like if both operands are plain objects, then both valueOf callbacks should be invoked:

var a = { valueOf: function() { trace("in a.valueOf"); } };
var b = { valueOf: function() { trace("in b.valueOf"); } };
trace(a < b); // traces "a.valueOf", "b.valueOf"
trace(b < a); // traces "b.valueOf", "a.valueOf"

If I get it right, Ruffle with this PR would bail-out early and invoke only the first valueOf.
So I think the correct order is something like this:

  1. a.to_primitive_num()
  2. b.to_primitive_num()
  3. if prim_self is an object, return false
  4. if prim_other is an object, return false

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The PR runs this example correctly -- the valueOfs in this case return undefined and not an Object, so the early-exit doesn't happen.

The early-exit does happen if you add return {} to the valueOf calls.

}
let prim_other = other.to_primitive_num(activation)?;

if let (Value::String(a), Value::String(b)) = (&prim_self, &prim_other) {
return Ok(a.to_string().bytes().lt(b.to_string().bytes()).into());
if matches!(prim_other, Value::Object(o) if o.as_display_object().is_none()) {
return Ok(false.into());
}

let num_self = prim_self.primitive_as_number(activation);
let num_other = prim_other.primitive_as_number(activation);

Ok(num_self
.partial_cmp(&num_other)
.map(|o| o == std::cmp::Ordering::Less))
let result = match (prim_self, prim_other) {
(Value::String(a), Value::String(b)) => {
let a = a.to_string();
let b = b.to_string();
a.bytes().lt(b.bytes()).into()
}
(a, b) => {
// Coerce to number and compare, with any NaN resulting in undefined.
let a = a.primitive_as_number(activation);
let b = b.primitive_as_number(activation);
a.partial_cmp(&b).map_or(Value::Undefined, |o| {
Value::Bool(o == std::cmp::Ordering::Less)
})
}
};
Ok(result)
}

/// ECMA-262 2nd edition s. 11.9.3 Abstract equality comparison algorithm
Expand Down Expand Up @@ -583,19 +600,22 @@ mod test {
let a = Value::Number(1.0);
let b = Value::Number(2.0);

assert_eq!(a.abstract_lt(b, activation).unwrap(), Some(true));
assert_eq!(a.abstract_lt(b, activation).unwrap(), Value::Bool(true));

let nan = Value::Number(f64::NAN);
assert_eq!(a.abstract_lt(nan, activation).unwrap(), None);
assert_eq!(a.abstract_lt(nan, activation).unwrap(), Value::Undefined);

let inf = Value::Number(f64::INFINITY);
assert_eq!(a.abstract_lt(inf, activation).unwrap(), Some(true));
assert_eq!(a.abstract_lt(inf, activation).unwrap(), Value::Bool(true));

let neg_inf = Value::Number(f64::NEG_INFINITY);
assert_eq!(a.abstract_lt(neg_inf, activation).unwrap(), Some(false));
assert_eq!(
a.abstract_lt(neg_inf, activation).unwrap(),
Value::Bool(false)
);

let zero = Value::Number(0.0);
assert_eq!(a.abstract_lt(zero, activation).unwrap(), Some(false));
assert_eq!(a.abstract_lt(zero, activation).unwrap(), Value::Bool(false));

Ok(())
});
Expand All @@ -607,19 +627,22 @@ mod test {
let a = Value::Number(1.0);
let b = Value::Number(2.0);

assert_eq!(b.abstract_lt(a, activation).unwrap(), Some(false));
assert_eq!(b.abstract_lt(a, activation).unwrap(), Value::Bool(false));

let nan = Value::Number(f64::NAN);
assert_eq!(nan.abstract_lt(a, activation).unwrap(), None);
assert_eq!(nan.abstract_lt(a, activation).unwrap(), Value::Undefined);

let inf = Value::Number(f64::INFINITY);
assert_eq!(inf.abstract_lt(a, activation).unwrap(), Some(false));
assert_eq!(inf.abstract_lt(a, activation).unwrap(), Value::Bool(false));

let neg_inf = Value::Number(f64::NEG_INFINITY);
assert_eq!(neg_inf.abstract_lt(a, activation).unwrap(), Some(true));
assert_eq!(
neg_inf.abstract_lt(a, activation).unwrap(),
Value::Bool(true)
);

let zero = Value::Number(0.0);
assert_eq!(zero.abstract_lt(a, activation).unwrap(), Some(true));
assert_eq!(zero.abstract_lt(a, activation).unwrap(), Value::Bool(true));

Ok(())
});
Expand All @@ -631,7 +654,7 @@ mod test {
let a = Value::String(AvmString::new_utf8(activation.context.gc_context, "a"));
let b = Value::String(AvmString::new_utf8(activation.context.gc_context, "b"));

assert_eq!(a.abstract_lt(b, activation).unwrap(), Some(true));
assert_eq!(a.abstract_lt(b, activation).unwrap(), Value::Bool(true));

Ok(())
})
Expand All @@ -643,7 +666,7 @@ mod test {
let a = Value::String(AvmString::new_utf8(activation.context.gc_context, "a"));
let b = Value::String(AvmString::new_utf8(activation.context.gc_context, "b"));

assert_eq!(b.abstract_lt(a, activation).unwrap(), Some(false));
assert_eq!(b.abstract_lt(a, activation).unwrap(), Value::Bool(false));

Ok(())
})
Expand Down
2 changes: 1 addition & 1 deletion tests/tests/regression_tests.rs
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Expand Up @@ -684,7 +684,7 @@ swf_tests! {
(stage_property_representation, "avm1/stage_property_representation", 1),
(strictequals_swf6, "avm1/strictequals_swf6", 1),
(strictly_equals, "avm1/strictly_equals", 1),
#[ignore] (string_coercion, "avm1/string_coercion", 1),
(string_coercion, "avm1/string_coercion", 1),
(string_methods_negative_args, "avm1/string_methods_negative_args", 1),
(string_methods, "avm1/string_methods", 1),
(string_ops_swf6, "avm1/string_ops_swf6", 1),
Expand Down
51 changes: 51 additions & 0 deletions tests/tests/swfs/avm1/lessthan2_swf5/output.txt
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Expand Up @@ -1174,3 +1174,54 @@ true
// "A" < "A":
false

// {} < 0:
false

// {} < "0":
false

// {} < {}
false

// {valueOf} < 0
obj.valueOf returning 1
false

// 0 < {valueOf}
obj.valueOf returning 1
true

// {valueOf} < {}
obj.valueOf returning 1
false

// {} < {valueOf}
false

// {valueOf} < {valueOf}
obj.valueOf returning 1
obj.valueOf returning 1
false

// {} < {objNoValueOf}
false

// {objNoValueOf} < {}
obj.valueOf returning undefined
false

// {valueOf} < {objNoValueOf}
obj.valueOf returning 1
obj.valueOf returning undefined
false

// {objNoValueOf} < {valueOf}
obj.valueOf returning undefined
obj.valueOf returning 1
true

// {objNoValueOf} < {objNoValueOf}
obj.valueOf returning undefined
obj.valueOf returning undefined
false

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51 changes: 51 additions & 0 deletions tests/tests/swfs/avm1/lessthan2_swf6/output.txt
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Expand Up @@ -1174,3 +1174,54 @@ true
// "A" < "A":
false

// {} < 0:
false

// {} < "0":
false

// {} < {}
false

// {valueOf} < 0
obj.valueOf returning 1
false

// 0 < {valueOf}
obj.valueOf returning 1
true

// {valueOf} < {}
obj.valueOf returning 1
false

// {} < {valueOf}
false

// {valueOf} < {valueOf}
obj.valueOf returning 1
obj.valueOf returning 1
false

// {} < {objNoValueOf}
false

// {objNoValueOf} < {}
obj.valueOf returning undefined
false

// {valueOf} < {objNoValueOf}
obj.valueOf returning 1
obj.valueOf returning undefined
false

// {objNoValueOf} < {valueOf}
obj.valueOf returning undefined
obj.valueOf returning 1
true

// {objNoValueOf} < {objNoValueOf}
obj.valueOf returning undefined
obj.valueOf returning undefined
false

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51 changes: 51 additions & 0 deletions tests/tests/swfs/avm1/lessthan2_swf7/output.txt
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Expand Up @@ -1174,3 +1174,54 @@ true
// "A" < "A":
false

// {} < 0:
false

// {} < "0":
false

// {} < {}
false

// {valueOf} < 0
obj.valueOf returning 1
false

// 0 < {valueOf}
obj.valueOf returning 1
true

// {valueOf} < {}
obj.valueOf returning 1
false

// {} < {valueOf}
false

// {valueOf} < {valueOf}
obj.valueOf returning 1
obj.valueOf returning 1
false

// {} < {objNoValueOf}
false

// {objNoValueOf} < {}
obj.valueOf returning undefined
false

// {valueOf} < {objNoValueOf}
obj.valueOf returning 1
obj.valueOf returning undefined
undefined

// {objNoValueOf} < {valueOf}
obj.valueOf returning undefined
obj.valueOf returning 1
undefined

// {objNoValueOf} < {objNoValueOf}
obj.valueOf returning undefined
obj.valueOf returning undefined
undefined

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8 changes: 8 additions & 0 deletions tests/tests/swfs/avm1/string_coercion/output.txt
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Expand Up @@ -107,3 +107,11 @@ sX
NaN
NaN
NaN
Function toString tests
[type Function]
[type Function]
[type Function]
Function string tests, toString deleted
[type Function]
undefined
[type Function]
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