more nil/known checks before val.LengthInt

command/format/diff.go

@@ -856,7 +856,7 @@ func ctyGetAttrMaybeNull(val cty.Value, name string) cty.Value {
 }
 
 func ctyCollectionValues(val cty.Value) []cty.Value {
-	if !val.IsKnown() {
+	if !val.IsKnown() || val.IsNull() {
 		return nil
 	}
 

plans/objchange/compatible.go

@@ -64,7 +64,7 @@ func assertObjectCompatible(schema *configschema.Block, planned, actual cty.Valu
 				return errs
 			}
 		case configschema.NestingList, configschema.NestingMap, configschema.NestingSet:
-			if plannedV.IsKnown() && plannedV.LengthInt() == 1 {
+			if plannedV.IsKnown() && !plannedV.IsNull() && plannedV.LengthInt() == 1 {
 				elemVs := plannedV.AsValueSlice()
 				if allLeafValuesUnknown(elemVs[0]) {
 					return errs
@@ -84,7 +84,7 @@ func assertObjectCompatible(schema *configschema.Block, planned, actual cty.Valu
 			// whether there are dynamically-typed attributes inside. However,
 			// both support a similar-enough API that we can treat them the
 			// same for our purposes here.
-			if !plannedV.IsKnown() {
+			if !plannedV.IsKnown() || plannedV.IsNull() || actualV.IsNull() {
 				continue
 			}
 
@@ -129,7 +129,7 @@ func assertObjectCompatible(schema *configschema.Block, planned, actual cty.Valu
 					}
 				}
 			} else {
-				if !plannedV.IsKnown() {
+				if !plannedV.IsKnown() || plannedV.IsNull() || actualV.IsNull() {
 					continue
 				}
 				plannedL := plannedV.LengthInt()
@@ -153,7 +153,7 @@ func assertObjectCompatible(schema *configschema.Block, planned, actual cty.Valu
 			// content is also their key, and so we have no way to correlate
 			// them. Because of this, we simply verify that we still have the
 			// same number of elements.
-			if !plannedV.IsKnown() {
+			if !plannedV.IsKnown() || plannedV.IsNull() || actualV.IsNull() {
 				continue
 			}
 			plannedL := plannedV.LengthInt()
@@ -251,7 +251,7 @@ func assertValueCompatible(planned, actual cty.Value, path cty.Path) []error {
 		// so we can't correlate them properly. However, we will at least check
 		// to ensure that the number of elements is consistent, along with
 		// the general type-match checks we ran earlier in this function.
-		if planned.IsKnown() {
+		if planned.IsKnown() && !planned.IsNull() && !actual.IsNull() {
 			plannedL := planned.LengthInt()
 			actualL := actual.LengthInt()
 			if plannedL < actualL {

plans/objchange/objchange.go

@@ -92,8 +92,12 @@ func ProposedNewObject(schema *configschema.Block, prior, config cty.Value) cty.
 
 		case configschema.NestingList:
 			// Nested blocks are correlated by index.
-			if l := configV.LengthInt(); l > 0 {
-				newVals := make([]cty.Value, 0, l)
+			configVLen := 0
+			if configV.IsKnown() && !configV.IsNull() {
+				configVLen = configV.LengthInt()
+			}
+			if configVLen > 0 {
+				newVals := make([]cty.Value, 0, configVLen)
 				for it := configV.ElementIterator(); it.Next(); {
 					idx, configEV := it.Element()
 					if priorV.IsKnown() && (priorV.IsNull() || !priorV.HasIndex(idx).True()) {
@@ -130,8 +134,12 @@ func ProposedNewObject(schema *configschema.Block, prior, config cty.Value) cty.
 			// dynamically-typed attributes.
 			if configV.Type().IsObjectType() {
 				// Nested blocks are correlated by key.
-				if l := configV.LengthInt(); l > 0 {
-					newVals := make(map[string]cty.Value, l)
+				configVLen := 0
+				if configV.IsKnown() && !configV.IsNull() {
+					configVLen = configV.LengthInt()
+				}
+				if configVLen > 0 {
+					newVals := make(map[string]cty.Value, configVLen)
 					atys := configV.Type().AttributeTypes()
 					for name := range atys {
 						configEV := configV.GetAttr(name)
@@ -154,8 +162,12 @@ func ProposedNewObject(schema *configschema.Block, prior, config cty.Value) cty.
 					newV = cty.EmptyObjectVal
 				}
 			} else {
-				if l := configV.LengthInt(); l > 0 {
-					newVals := make(map[string]cty.Value, l)
+				configVLen := 0
+				if configV.IsKnown() && !configV.IsNull() {
+					configVLen = configV.LengthInt()
+				}
+				if configVLen > 0 {
+					newVals := make(map[string]cty.Value, configVLen)
 					for it := configV.ElementIterator(); it.Next(); {
 						idx, configEV := it.Element()
 						k := idx.AsString()
@@ -190,9 +202,13 @@ func ProposedNewObject(schema *configschema.Block, prior, config cty.Value) cty.
 			if priorV.IsKnown() && !priorV.IsNull() {
 				cmpVals = setElementCompareValues(&blockType.Block, priorV, false)
 			}
-			if l := configV.LengthInt(); l > 0 {
+			configVLen := 0
+			if configV.IsKnown() && !configV.IsNull() {
+				configVLen = configV.LengthInt()
+			}
+			if configVLen > 0 {
 				used := make([]bool, len(cmpVals)) // track used elements in case multiple have the same compare value
-				newVals := make([]cty.Value, 0, l)
+				newVals := make([]cty.Value, 0, configVLen)
 				for it := configV.ElementIterator(); it.Next(); {
 					_, configEV := it.Element()
 					var priorEV cty.Value