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- improved handling of return value mismatches

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Prohibit returning more values than declared in function
The exception is a void function returning one value, but only for compatibility with old scripts

https://forum.zdoom.org/viewtopic.php?t=66341
This commit is contained in:
alexey.lysiuk 2019-11-10 11:14:08 +02:00
parent 8c05816378
commit 6ad965abb5
1 changed files with 28 additions and 11 deletions
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39
src/scripting/backend/codegen.cpp
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@ -10716,27 +10716,44 @@ FxExpression *FxReturnStatement::Resolve(FCompileContext &ctx)
PPrototype *retproto;
if (ctx.ReturnProto != nullptr && ctx.ReturnProto->ReturnTypes.Size() == 0 && ctx.ReturnProto->ReturnTypes.Size() != Args.Size())
const bool hasProto = ctx.ReturnProto != nullptr;
const unsigned protoRetCount = hasProto ? ctx.ReturnProto->ReturnTypes.Size() : 0;
const unsigned retCount = Args.Size();
int mismatchSeverity = -1;
if (hasProto)
{
int severity = ctx.Version >= MakeVersion(3, 7) ? MSG_ERROR : MSG_WARNING;
ScriptPosition.Message(severity, "Incorrect number of return values. Got %u, but expected %u", Args.Size(), ctx.ReturnProto->ReturnTypes.Size());
if (severity == MSG_ERROR)
if (protoRetCount == 0 && retCount == 1)
{
// Handle the case with void function returning something, but only for one value
// It was accepted in previous versions, do not abort with fatal error when compiling old scripts
mismatchSeverity = ctx.Version >= MakeVersion(3, 7) ? MSG_ERROR : MSG_WARNING;
}
else if (protoRetCount < retCount)
{
mismatchSeverity = MSG_ERROR;
}
}
if (mismatchSeverity != -1)
{
ScriptPosition.Message(mismatchSeverity, "Incorrect number of return values. Got %u, but expected %u", Args.Size(), ctx.ReturnProto->ReturnTypes.Size());
if (mismatchSeverity == MSG_ERROR)
{
delete this;
return nullptr;
}
// For older script versions this must fall through.
}
if (Args.Size() == 0)
if (retCount == 0)
{
TArray<PType *> none(0);
retproto = NewPrototype(none, none);
}
else if (Args.Size() == 1)
else if (retCount == 1)
{
// If we already know the real return type we need at least try to cast the value to its proper type (unless in an anonymous function.)
if (ctx.ReturnProto != nullptr && ctx.ReturnProto->ReturnTypes.Size() > 0 && ctx.Function->SymbolName != NAME_None)
if (hasProto && protoRetCount > 0 && ctx.Function->SymbolName != NAME_None)
{
Args[0] = new FxTypeCast(Args[0], ctx.ReturnProto->ReturnTypes[0], false, false);
Args[0] = Args[0]->Resolve(ctx);
@ -10746,7 +10763,7 @@ FxExpression *FxReturnStatement::Resolve(FCompileContext &ctx)
}
else
{
for (unsigned i = 0; i < Args.Size(); i++)
for (unsigned i = 0; i < retCount; i++)
{
Args[i] = new FxTypeCast(Args[i], ctx.ReturnProto->ReturnTypes[i], false, false);
Args[i] = Args[i]->Resolve(ctx);
@ -11906,4 +11923,4 @@ ExpEmit FxOutVarDereference::Emit(VMFunctionBuilder *build)
selfEmit.Free(build);
return out;
}
}