When an interpreter type implementing an interface is
used by the runtime, the runtime can extract its type
and create new values using reflect, and call methods
on it. The problem is that there will be no interpreted
method counterpart in this case, which makes wrapper panic.
Allow the String() method wrapper to always succeed and
return an empty string if no interpreted method is present.
This allows scripts to define custom flag.Value types on
which the runtime internally instantiates values using
reflect (see isZeroValue in Go src/flag/flag.go).
This workaround could be generalized to all wrappers if
necessary. At this moment, it is convenient to keep the
default behavior of expecting instantiated interpreter
methods, in order to catch interpreter bugs related to
interfaces.
Fixes#1276.
This change fixes a regression introduced by PR #1192 in a program using
https://github.com/NYTimes/gziphandler which defines several types
implementing stdlib interfaces. We do not implement a wrapper
if we see that a type already implements an interface, except that
it can be falsly reported by reflect in case of a struct with
embedded interface field. We need to force the wrapper generation
in this case.
The problem occurs only for wrappers on struct, not on pointers or
other indirection types.
This test (assert2.go) display 2 separate issues:
1. assert2.go L28: Type assert tries to set an `interface{}` to a `valueInterface`. The typing here is complex, we have a valueT(strings.Builder) wrapped in a ptrT wrapped in a src iface wrapped in a valueT(interface{}). Type assert fails to realise that the `valueT` `interface{}` is wrapping the `valueInterface`.
2. assert2.go L29: `genValueBinMethodOnInterface` does not try and get the bin method, as the `typ.node` (`ptrT` or a `valueT`(`string.Builder`)) is set. In this case the src iface is called with a receiver argument. To fix this the method is looked for first if possible, and only if not found does it fall back to the `defaultGen`.
Fixes#1227
As the unsafe and pointer methods in `reflect` are to be depreciated, and seeing no replacement functions, it is now forced that some unsafe is needed to replace this as when and interface is dereferenced it is made unsettable by reflect.
With this in mind, this adds real recursive types by hot swapping the struct field type on the fly. This removes a lot of compensation code, simplifying all previous cases.
**Note:** While the struct field type is swapped for the real type, the type string is not changed. Due to this, unsafe will recreate the same type.
This adds `itype.str` which is a string representation of the type built when the type is built. The goal is to make type comparison simpler and centralise the creation of types just to constructors and `nodeType`. `nodeType` continues to build types in parts so to reuse underlying types better.
When calling a function, if the input param is a "zero" instance, it is not set on the input. This is an issue where the param is an `interface{}` as a `nil` value is set instead of the zero value.
The actual solution for this is to remove the `if !val.IsZero()`, this however runs into an issue on `_test/struct48.go` where we have a zero recursive struct instance (`*interface{}`) and we have no way to get its real type. Should a way be figured out to keep tabs on the original type, the `if` can go away, and in the zero case of `genValueRecursiveInterfacePtrValue`, the actual zero type can be returned.
Fixes#1215
Add getConcreteType to retrieve the concrete type of a nested interface
value implementing a specific interface for which a wrapper exists.
If method resolution fails at runtime, a panic is now issued instead
of an error message and continue.
Fixes#1187.
Map handling builtins getIndexMap and rangeMap had some leftover
code of previous way of emulating interfaces, which was modified
following changes in #1017.
Specific code for interfaceT is removed, as not necessary anymore.
Map builtins are now simplified and more robust.
Fixes#1189.
Add early detection of cases where no wrapper is necessary because
the value type already implements the target interface.
It should both increase performances by avoiding the wrapper overhead,
and fix errors due to replacing valid values by incomplete wrappers,
caused by the presence of private methods in the interface definition,
as in #1191.
Fixes#1191.
Store the interpreter value of the interface object to wrap as
a field called IValue, at offset 0 in wrapper structures.
Update extract to include IValue field.
In typeAssert, detect interface wrapper, and dereference the
interpreter value from IValue wrapper field.
Fixes#1166.
In selector resolution, struct field matching now precedes
method matching. Before struct field matching could be skipped
in case of a matching method, which is incorrect, as demontrated
by _test/issue-1156.go.
Field lookup has been fixed to operate on recursive structures.
Concrete type values are derived when filling a receiver for
interface methods.
LookupBinField has been fixed to skip non struct values.
LookupMethod has been fixed to iterate on interface values as
well as concrete type values.
Fixes#1156.
Fixes#1150
1. When resolving a selector expression involving an aliased type, resolve the aliased type
2. When building an array literal, resolve the aliased type
Aliases of named array and slice types were the only ones that didn't work, but I added the other test cases for the sake of completeness and through testing.
Fixes#1149
Because of how aliases are handled, `n.gen` is set to `getIndexSeqMethod` or `getIndexSeqPtrMethod` in cases like the one described in #1149. As a result, `FieldByIndex` can be called on a value that is not a struct, which causes a panic. This MR updates those two methods to avoid that call if the index array is empty.
The case of assigning a binary function to a funcT object was
solved elsewhere. Factor the case in genDestValue to apply it
at multiple places.
Fixes#1100.
In this range variant "for k, v := range aString", k must
be the byte position of the rune in the byte array, rather than
the index of the rune in the rune array.
Fixes#1088.
In that case, direct propagation of result can not be attempted,
as the frame types will be different between the source and destination.
Disabling the optimisation and using The regular case involves an intermediate
frame entry, which enables the type conversion.
Fixes#1091.
Interpreted functions were represented in an inconsistent way in the frame: as a node pointer by default, and wrapped in a function wrapper for maps.
We now simply use the default (*node) representation, as elsewhere, so values can be assigned, passed and called as for the other types. The alternative (generating a function wrapper) is more complex, costly and reserved for cases where the interpreted function can be called from the runtime.
Test that a map of functions can store both binary functions from used packages and interpreted ones.
Fixes#1090.
Avoid to test directly for a type category, as it may give wrong
results for aliased types, where the interesting category remains
masked. Instead, use some property helpers, such as isFuncSrc,
isPtrSrc and isInterfaceSrc to check if a type is of source function,
source pointer or source interface respectively (versus runtime
defined function, pointer or interface).
Fixes#1068.
Add missing `sliceT` type category for consistency. Remove
`sizedef` field in `itype` struct. Rename field `size` to `length`.
Clean the various hacks used to cope with the absence of `sliceT`.
Functions in a struct fields are always wrapped (as potentially
used by the runtime), so generate a function wrapper also for
closure when assigned to a struct field.
When such a function is called from the interpreter, ensure that
interface arguments are also wrapped so method and receiver resolution
can be performed.
Fixes partially #1043.
The first change forces a variable definition to reallocate a
new memory slot to avoid corrupting a previously defined one in
a loop block.
The second change ensures that the frame clone operations obtains
a copy of the original data slice, to preserve the original context
set in a loop.
Fixes#1035.
As mentioned in #1030, when an Eval panic, it is print with `fmt.Println()` and not to the configured `interp.Options.Stderr`. According to https://github.com/traefik/yaegi/blob/master/interp/interp.go#L210, it should be removed in future version so I'm not sure if this pull request is necessary. However, it could fix the issue in the meanwhile.
Fixes#1030.
This is a follow-up of #1017, generalizing the use of reflect.Set
method to set, and possibly overwrite, the concrete value of
interface objects all accross the implementation of operators.
Previous optimized implementation for non-interface objects is
preserved.
The empty interface (interface{}), and its variants (such as []interface{} and map[string]interface{}), are commonly used in Go to (json) Unmarshal arbitrary data. Within Yaegi, all interface types are wrapped in a valueInterface struct in order to retain all the information needed for a consistent internal state (as reflect is not enough to achieve that). However, this wrapping ends up being problematic when it comes to the type assertions related to the aforementioned Unmarshaling.
Therefore, this PR is an attempt to consider the empty interface (and its variants) as an exception within Yaegi, that should never be wrapped within a valueInterface, and to treat it similarly to the other basic Go types. The assumption is that the wrapping should not be needed, as there is no information about implemented methods to maintain.
Fixes#984Fixes#829Fixes#1015
When passing a function reference as an interface in a composite binary map, the case should be handled to not take the value of the the node.
Related to #886
A channel can be used to interchange data with the pre-compiled
runtime and therefore objects impletementing interfaces must be
wrapped if necessary, using genInterfaceWrapper.
A similar treatment could be applied when sending interpreted
functions over a channel, to be provided in a new PR.
Fixes#1010.
In some cases, the global character of a value was lost, leading to
undefined behaviour. Now a node level field of -1 means that the value
is global, and that it should be accessed from the root data frame.
Fixes#993.
The interpreter interface type was replaced by a reflect.Value in
objects passed or return to function wrappers, losing the ability
to retrieve methods.
The valueInterface is now preserved, and correctly accessed if
wrapped multiple times.
Fixes#977.
typeAssertStatus deals with the 3rd form of type assertion ("_, ok"), for
when one does not care about the result of the assertion itself.
Some cases for it, which are already fixed for the two other forms of
type assertions, had not been fixed for this form yet.
Therefore, this change fixes such cases for this form, while integrating
typeAssertStatus to the same code path as for the two other forms.
The long-form (with comma-ok) ones were already fixed but the short-form
ones were not because they were in a completely different code path.
This PR also refactors the code so that both short-form and long-form
are now merged in the same function.
N.B: even though most (all?) cases seem to now be supported, one of them
still yields a result that does not satisfy reflect's Implements method
yet. It does not prevent the resulting assertion to be usable though.
N.B2: the code path for the third-form (_, ok) hasn't been fixed and/or
refactored yet.
Fixes#919
