Extend hcl2 support with more functions

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/zclconf/go-cty/cty/function/stdlib/collection.go

@@ -138,6 +138,13 @@ var ElementFunc = function.New(&function.Spec{
 	},
 	Type: func(args []cty.Value) (cty.Type, error) {
 		list := args[0]
+		index := args[1]
+		if index.IsKnown() {
+			if index.LessThan(cty.NumberIntVal(0)).True() {
+				return cty.DynamicPseudoType, fmt.Errorf("cannot use element function with a negative index")
+			}
+		}
+
 		listTy := list.Type()
 		switch {
 		case listTy.IsListType():
@@ -173,6 +180,10 @@ var ElementFunc = function.New(&function.Spec{
 			return cty.DynamicVal, fmt.Errorf("invalid index: %s", err)
 		}
 
+		if args[1].LessThan(cty.NumberIntVal(0)).True() {
+			return cty.DynamicVal, fmt.Errorf("cannot use element function with a negative index")
+		}
+
 		if !args[0].IsKnown() {
 			return cty.UnknownVal(retType), nil
 		}
@@ -240,6 +251,10 @@ var CoalesceListFunc = function.New(&function.Spec{
 				return cty.UnknownVal(retType), nil
 			}
 
+			if arg.IsNull() {
+				continue
+			}
+
 			if arg.LengthInt() > 0 {
 				return arg, nil
 			}
@@ -492,6 +507,11 @@ var FlattenFunc = function.New(&function.Spec{
 // We can flatten lists with unknown values, as long as they are not
 // lists themselves.
 func flattener(flattenList cty.Value) ([]cty.Value, bool) {
+	if !flattenList.Length().IsKnown() {
+		// If we don't know the length of what we're flattening then we can't
+		// predict the length of our result yet either.
+		return nil, false
+	}
 	out := make([]cty.Value, 0)
 	for it := flattenList.ElementIterator(); it.Next(); {
 		_, val := it.Element()
@@ -742,16 +762,10 @@ var MergeFunc = function.New(&function.Spec{
 	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
 		outputMap := make(map[string]cty.Value)
 
-		// if all inputs are null, return a null value rather than an object
-		// with null attributes
-		allNull := true
 		for _, arg := range args {
 			if arg.IsNull() {
 				continue
-			} else {
-				allNull = false
 			}
-
 			for it := arg.ElementIterator(); it.Next(); {
 				k, v := it.Element()
 				outputMap[k.AsString()] = v
@@ -759,9 +773,10 @@ var MergeFunc = function.New(&function.Spec{
 		}
 
 		switch {
-		case allNull:
-			return cty.NullVal(retType), nil
 		case retType.IsMapType():
+			if len(outputMap) == 0 {
+				return cty.MapValEmpty(retType.ElementType()), nil
+			}
 			return cty.MapVal(outputMap), nil
 		case retType.IsObjectType(), retType.Equals(cty.DynamicPseudoType):
 			return cty.ObjectVal(outputMap), nil
@@ -869,6 +884,10 @@ var SetProductFunc = function.New(&function.Spec{
 
 		total := 1
 		for _, arg := range args {
+			if !arg.Length().IsKnown() {
+				return cty.UnknownVal(retType), nil
+			}
+
 			// Because of our type checking function, we are guaranteed that
 			// all of the arguments are known, non-null values of types that
 			// support LengthInt.
@@ -1016,7 +1035,8 @@ func sliceIndexes(args []cty.Value) (int, int, bool, error) {
 	var startIndex, endIndex, length int
 	var startKnown, endKnown, lengthKnown bool
 
-	if args[0].Type().IsTupleType() || args[0].IsKnown() { // if it's a tuple then we always know the length by the type, but lists must be known
+	// If it's a tuple then we always know the length by the type, but collections might be unknown or have unknown length
+	if args[0].Type().IsTupleType() || args[0].Length().IsKnown() {
 		length = args[0].LengthInt()
 		lengthKnown = true
 	}

vendor/github.com/zclconf/go-cty/cty/function/stdlib/datetime.go

@@ -362,9 +362,14 @@ func splitDateFormat(data []byte, atEOF bool) (advance int, token []byte, err er
 		for i := 1; i < len(data); i++ {
 			if data[i] == esc {
 				if (i + 1) == len(data) {
-					// We need at least one more byte to decide if this is an
-					// escape or a terminator.
-					return 0, nil, nil
+					if atEOF {
+						// We have a closing quote and are at the end of our input
+						return len(data), data, nil
+					} else {
+						// We need at least one more byte to decide if this is an
+						// escape or a terminator.
+						return 0, nil, nil
+					}
 				}
 				if data[i+1] == esc {
 					i++ // doubled-up quotes are an escape sequence

vendor/github.com/zclconf/go-cty/cty/function/stdlib/format.go

@@ -85,7 +85,7 @@ var FormatListFunc = function.New(&function.Spec{
 			argTy := arg.Type()
 			switch {
 			case (argTy.IsListType() || argTy.IsSetType() || argTy.IsTupleType()) && !arg.IsNull():
-				if !argTy.IsTupleType() && !arg.IsKnown() {
+				if !argTy.IsTupleType() && !(arg.IsKnown() && arg.Length().IsKnown()) {
 					// We can't iterate this one at all yet then, so we can't
 					// yet produce a result.
 					unknowns[i] = true

vendor/github.com/zclconf/go-cty/cty/function/stdlib/json.go

@@ -12,6 +12,7 @@ var JSONEncodeFunc = function.New(&function.Spec{
 			Name:             "val",
 			Type:             cty.DynamicPseudoType,
 			AllowDynamicType: true,
+			AllowNull:        true,
 		},
 	},
 	Type: function.StaticReturnType(cty.String),
@@ -24,6 +25,10 @@ var JSONEncodeFunc = function.New(&function.Spec{
 			return cty.UnknownVal(retType), nil
 		}
 
+		if val.IsNull() {
+			return cty.StringVal("null"), nil
+		}
+
 		buf, err := json.Marshal(val, val.Type())
 		if err != nil {
 			return cty.NilVal, err

vendor/github.com/zclconf/go-cty/cty/function/stdlib/set.go

@@ -44,7 +44,7 @@ var SetUnionFunc = function.New(&function.Spec{
 	Type: setOperationReturnType,
 	Impl: setOperationImpl(func(s1, s2 cty.ValueSet) cty.ValueSet {
 		return s1.Union(s2)
-	}),
+	}, true),
 })
 
 var SetIntersectionFunc = function.New(&function.Spec{
@@ -63,7 +63,7 @@ var SetIntersectionFunc = function.New(&function.Spec{
 	Type: setOperationReturnType,
 	Impl: setOperationImpl(func(s1, s2 cty.ValueSet) cty.ValueSet {
 		return s1.Intersection(s2)
-	}),
+	}, false),
 })
 
 var SetSubtractFunc = function.New(&function.Spec{
@@ -82,7 +82,7 @@ var SetSubtractFunc = function.New(&function.Spec{
 	Type: setOperationReturnType,
 	Impl: setOperationImpl(func(s1, s2 cty.ValueSet) cty.ValueSet {
 		return s1.Subtract(s2)
-	}),
+	}, false),
 })
 
 var SetSymmetricDifferenceFunc = function.New(&function.Spec{
@@ -100,8 +100,8 @@ var SetSymmetricDifferenceFunc = function.New(&function.Spec{
 	},
 	Type: setOperationReturnType,
 	Impl: setOperationImpl(func(s1, s2 cty.ValueSet) cty.ValueSet {
-		return s1.Subtract(s2)
-	}),
+		return s1.SymmetricDifference(s2)
+	}, false),
 })
 
 // SetHasElement determines whether the given set contains the given value as an
@@ -163,8 +163,23 @@ func SetSymmetricDifference(sets ...cty.Value) (cty.Value, error) {
 func setOperationReturnType(args []cty.Value) (ret cty.Type, err error) {
 	var etys []cty.Type
 	for _, arg := range args {
-		etys = append(etys, arg.Type().ElementType())
+		ty := arg.Type().ElementType()
+
+		// Do not unify types for empty dynamic pseudo typed collections. These
+		// will always convert to any other concrete type.
+		if arg.IsKnown() && arg.LengthInt() == 0 && ty.Equals(cty.DynamicPseudoType) {
+			continue
+		}
+
+		etys = append(etys, ty)
 	}
+
+	// If all element types were skipped (due to being empty dynamic collections),
+	// the return type should also be a set of dynamic pseudo type.
+	if len(etys) == 0 {
+		return cty.Set(cty.DynamicPseudoType), nil
+	}
+
 	newEty, _ := convert.UnifyUnsafe(etys)
 	if newEty == cty.NilType {
 		return cty.NilType, fmt.Errorf("given sets must all have compatible element types")
@@ -172,13 +187,21 @@ func setOperationReturnType(args []cty.Value) (ret cty.Type, err error) {
 	return cty.Set(newEty), nil
 }
 
-func setOperationImpl(f func(s1, s2 cty.ValueSet) cty.ValueSet) function.ImplFunc {
+func setOperationImpl(f func(s1, s2 cty.ValueSet) cty.ValueSet, allowUnknowns bool) function.ImplFunc {
 	return func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
 		first := args[0]
 		first, err = convert.Convert(first, retType)
 		if err != nil {
 			return cty.NilVal, function.NewArgError(0, err)
 		}
+		if !allowUnknowns && !first.IsWhollyKnown() {
+			// This set function can produce a correct result only when all
+			// elements are known, because eventually knowing the unknown
+			// values may cause the result to have fewer known elements, or
+			// might cause a result with no unknown elements at all to become
+			// one with a different length.
+			return cty.UnknownVal(retType), nil
+		}
 
 		set := first.AsValueSet()
 		for i, arg := range args[1:] {
@@ -186,6 +209,10 @@ func setOperationImpl(f func(s1, s2 cty.ValueSet) cty.ValueSet) function.ImplFun
 			if err != nil {
 				return cty.NilVal, function.NewArgError(i+1, err)
 			}
+			if !allowUnknowns && !arg.IsWhollyKnown() {
+				// (For the same reason as we did this check for "first" above.)
+				return cty.UnknownVal(retType), nil
+			}
 
 			argSet := arg.AsValueSet()
 			set = f(set, argSet)