Handle nullable items in Go arrays

Created by: therve

If an item in a go array is nullable, we want to represent it as a pointer, otherwise it will be deserialized with a default value and it will be impossible to differentiate it from null.

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modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java

@@ -350,6 +350,9 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
             } else {
                 typDecl = "interface{}";
             }
+	    if (Boolean.TRUE.equals(inner.getNullable())) {
+		typDecl = "*" + typDecl;
+	    }
             return "[]" + typDecl;
         } else if (ModelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java

@@ -544,6 +544,10 @@ public class GoClientCodegen extends AbstractGoCodegen {
             if (modelMaps.containsKey(dataType)) {
                 prefix = "[]" + goImportAlias + "." + dataType;
             }
+            if (codegenProperty.items.isNullable) {
+                // We can't easily generate a pointer inline, so just use nil in that case
+                return prefix + "{nil}";
+            }
             return prefix + "{" + constructExampleCode(codegenProperty.items, modelMaps, processedModelMap) + "}";
         } else if (codegenProperty.isMap) { // map
             String prefix = codegenProperty.dataType;

samples/openapi3/client/petstore/go/go-petstore/docs/NullableClass.md

@@ -283,20 +283,20 @@ HasArrayNullableProp returns a boolean if a field has been set.
 UnsetArrayNullableProp ensures that no value is present for ArrayNullableProp, not even an explicit nil
 ### GetArrayAndItemsNullableProp
 
-`func (o *NullableClass) GetArrayAndItemsNullableProp() []map[string]interface{}`
+`func (o *NullableClass) GetArrayAndItemsNullableProp() []*map[string]interface{}`
 
 GetArrayAndItemsNullableProp returns the ArrayAndItemsNullableProp field if non-nil, zero value otherwise.
 
 ### GetArrayAndItemsNullablePropOk
 
-`func (o *NullableClass) GetArrayAndItemsNullablePropOk() (*[]map[string]interface{}, bool)`
+`func (o *NullableClass) GetArrayAndItemsNullablePropOk() (*[]*map[string]interface{}, bool)`
 
 GetArrayAndItemsNullablePropOk returns a tuple with the ArrayAndItemsNullableProp field if it's non-nil, zero value otherwise
 and a boolean to check if the value has been set.
 
 ### SetArrayAndItemsNullableProp
 
-`func (o *NullableClass) SetArrayAndItemsNullableProp(v []map[string]interface{})`
+`func (o *NullableClass) SetArrayAndItemsNullableProp(v []*map[string]interface{})`
 
 SetArrayAndItemsNullableProp sets ArrayAndItemsNullableProp field to given value.
 
@@ -318,20 +318,20 @@ HasArrayAndItemsNullableProp returns a boolean if a field has been set.
 UnsetArrayAndItemsNullableProp ensures that no value is present for ArrayAndItemsNullableProp, not even an explicit nil
 ### GetArrayItemsNullable
 
-`func (o *NullableClass) GetArrayItemsNullable() []map[string]interface{}`
+`func (o *NullableClass) GetArrayItemsNullable() []*map[string]interface{}`
 
 GetArrayItemsNullable returns the ArrayItemsNullable field if non-nil, zero value otherwise.
 
 ### GetArrayItemsNullableOk
 
-`func (o *NullableClass) GetArrayItemsNullableOk() (*[]map[string]interface{}, bool)`
+`func (o *NullableClass) GetArrayItemsNullableOk() (*[]*map[string]interface{}, bool)`
 
 GetArrayItemsNullableOk returns a tuple with the ArrayItemsNullable field if it's non-nil, zero value otherwise
 and a boolean to check if the value has been set.
 
 ### SetArrayItemsNullable
 
-`func (o *NullableClass) SetArrayItemsNullable(v []map[string]interface{})`
+`func (o *NullableClass) SetArrayItemsNullable(v []*map[string]interface{})`
 
 SetArrayItemsNullable sets ArrayItemsNullable field to given value.
 

samples/openapi3/client/petstore/go/go-petstore/model_nullable_class.go

@@ -24,8 +24,8 @@ type NullableClass struct {
 	DateProp NullableString `json:"date_prop,omitempty"`
 	DatetimeProp NullableTime `json:"datetime_prop,omitempty"`
 	ArrayNullableProp []map[string]interface{} `json:"array_nullable_prop,omitempty"`
-	ArrayAndItemsNullableProp []map[string]interface{} `json:"array_and_items_nullable_prop,omitempty"`
-	ArrayItemsNullable *[]map[string]interface{} `json:"array_items_nullable,omitempty"`
+	ArrayAndItemsNullableProp []*map[string]interface{} `json:"array_and_items_nullable_prop,omitempty"`
+	ArrayItemsNullable *[]*map[string]interface{} `json:"array_items_nullable,omitempty"`
 	ObjectNullableProp map[string]map[string]interface{} `json:"object_nullable_prop,omitempty"`
 	ObjectAndItemsNullableProp map[string]map[string]interface{} `json:"object_and_items_nullable_prop,omitempty"`
 	ObjectItemsNullable *map[string]map[string]interface{} `json:"object_items_nullable,omitempty"`
@@ -338,9 +338,9 @@ func (o *NullableClass) SetArrayNullableProp(v []map[string]interface{}) {
 }
 
 // GetArrayAndItemsNullableProp returns the ArrayAndItemsNullableProp field value if set, zero value otherwise (both if not set or set to explicit null).
-func (o *NullableClass) GetArrayAndItemsNullableProp() []map[string]interface{} {
+func (o *NullableClass) GetArrayAndItemsNullableProp() []*map[string]interface{} {
 	if o == nil  {
-		var ret []map[string]interface{}
+		var ret []*map[string]interface{}
 		return ret
 	}
 	return o.ArrayAndItemsNullableProp
@@ -349,7 +349,7 @@ func (o *NullableClass) GetArrayAndItemsNullableProp() []map[string]interface{}
 // GetArrayAndItemsNullablePropOk returns a tuple with the ArrayAndItemsNullableProp field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
-func (o *NullableClass) GetArrayAndItemsNullablePropOk() (*[]map[string]interface{}, bool) {
+func (o *NullableClass) GetArrayAndItemsNullablePropOk() (*[]*map[string]interface{}, bool) {
 	if o == nil || o.ArrayAndItemsNullableProp == nil {
 		return nil, false
 	}
@@ -365,15 +365,15 @@ func (o *NullableClass) HasArrayAndItemsNullableProp() bool {
 	return false
 }
 
-// SetArrayAndItemsNullableProp gets a reference to the given []map[string]interface{} and assigns it to the ArrayAndItemsNullableProp field.
-func (o *NullableClass) SetArrayAndItemsNullableProp(v []map[string]interface{}) {
+// SetArrayAndItemsNullableProp gets a reference to the given []*map[string]interface{} and assigns it to the ArrayAndItemsNullableProp field.
+func (o *NullableClass) SetArrayAndItemsNullableProp(v []*map[string]interface{}) {
 	o.ArrayAndItemsNullableProp = v
 }
 
 // GetArrayItemsNullable returns the ArrayItemsNullable field value if set, zero value otherwise.
-func (o *NullableClass) GetArrayItemsNullable() []map[string]interface{} {
+func (o *NullableClass) GetArrayItemsNullable() []*map[string]interface{} {
 	if o == nil || o.ArrayItemsNullable == nil {
-		var ret []map[string]interface{}
+		var ret []*map[string]interface{}
 		return ret
 	}
 	return *o.ArrayItemsNullable
@@ -381,7 +381,7 @@ func (o *NullableClass) GetArrayItemsNullable() []map[string]interface{} {
 
 // GetArrayItemsNullableOk returns a tuple with the ArrayItemsNullable field value if set, nil otherwise
 // and a boolean to check if the value has been set.
-func (o *NullableClass) GetArrayItemsNullableOk() (*[]map[string]interface{}, bool) {
+func (o *NullableClass) GetArrayItemsNullableOk() (*[]*map[string]interface{}, bool) {
 	if o == nil || o.ArrayItemsNullable == nil {
 		return nil, false
 	}
@@ -397,8 +397,8 @@ func (o *NullableClass) HasArrayItemsNullable() bool {
 	return false
 }
 
-// SetArrayItemsNullable gets a reference to the given []map[string]interface{} and assigns it to the ArrayItemsNullable field.
-func (o *NullableClass) SetArrayItemsNullable(v []map[string]interface{}) {
+// SetArrayItemsNullable gets a reference to the given []*map[string]interface{} and assigns it to the ArrayItemsNullable field.
+func (o *NullableClass) SetArrayItemsNullable(v []*map[string]interface{}) {
 	o.ArrayItemsNullable = &v
 }