Type check of array element only when array is not empty. fix #21276 (#21571)

mikkomaunu · web-flow · commit d82ca75cc3ed · 2025-07-17T01:30:31.000+08:00
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/anyof_model.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/anyof_model.mustache
@@ -81,7 +81,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
                     {{^isPrimitiveType}}
                     {{#isArray}}
                         List<?> list = (List<?>) value.getActualInstance();
-                        if (list.get(0) instanceof {{{items.dataType}}}) {
+                        if (!list.isEmpty() && list.get(0) instanceof {{{items.dataType}}}) {
                             JsonArray array = adapter{{#sanitizeDataType}}{{{dataType}}}{{/sanitizeDataType}}.toJsonTree(({{{dataType}}})value.getActualInstance()).getAsJsonArray();
                             elementAdapter.write(out, array);
                             return;
@@ -252,7 +252,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
         if (instance instanceof {{#isArray}}List<?>{{/isArray}}{{^isArray}}{{{dataType}}}{{/isArray}}) {
         {{#isArray}}
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof {{{items.dataType}}}) {
+            if (!list.isEmpty() && list.get(0) instanceof {{{items.dataType}}}) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/oneof_model.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/oneof_model.mustache
@@ -94,7 +94,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
                     {{^isPrimitiveType}}
                     {{#isArray}}
                         List<?> list = (List<?>) value.getActualInstance();
-                        if (list.get(0) instanceof {{{items.dataType}}}) {
+                        if (!list.isEmpty() && list.get(0) instanceof {{{items.dataType}}}) {
                             JsonArray array = adapter{{#sanitizeDataType}}{{{dataType}}}{{/sanitizeDataType}}.toJsonTree(({{{dataType}}})value.getActualInstance()).getAsJsonArray();
                             elementAdapter.write(out, array);
                             return;
@@ -330,7 +330,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
         if (instance instanceof {{#isArray}}List<?>{{/isArray}}{{#isMap}}Map<?, ?>{{/isMap}}{{^isMap}}{{^isArray}}{{{dataType}}}{{/isArray}}{{/isMap}}) {
         {{#isArray}}
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof {{{items.dataType}}}) {
+            if (!list.isEmpty() && list.get(0) instanceof {{{items.dataType}}}) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/anyof_class.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/anyof_class.mustache
@@ -110,7 +110,7 @@ import java.io.IOException
                     if (value.actualInstance is {{#isArray}}List<*>{{/isArray}}{{^isArray}}{{{dataType}}}{{/isArray}}) {
                     {{#isArray}}
                         val list = value.actualInstance as List<Any>
-                        if (list.get(0) is {{{items.dataType}}}) {
+                        if (!list.isEmpty() && list.get(0) is {{{items.dataType}}}) {
                             val array = adapter{{#sanitizeGeneric}}{{{dataType}}}{{/sanitizeGeneric}}.toJsonTree(value.actualInstance as {{{dataType}}}?).getAsJsonArray()
                             elementAdapter.write(out, array)
                             return
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/oneof_class.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/oneof_class.mustache
@@ -110,7 +110,7 @@ import java.io.IOException
                     if (value.actualInstance is {{#isArray}}List<*>{{/isArray}}{{^isArray}}{{{dataType}}}{{/isArray}}) {
                     {{#isArray}}
                         val list = value.actualInstance as List<Any>
-                        if (list.get(0) is {{{items.dataType}}}) {
+                        if (!list.isEmpty() && list.get(0) is {{{items.dataType}}}) {
                             val array = adapter{{#sanitizeGeneric}}{{{dataType}}}{{/sanitizeGeneric}}.toJsonTree(value.actualInstance as {{{dataType}}}?).getAsJsonArray()
                             elementAdapter.write(out, array)
                             return
diff --git a/samples/client/others/java/okhttp-gson-oneOf-array/src/main/java/org/openapitools/client/model/MyExampleGet200Response.java b/samples/client/others/java/okhttp-gson-oneOf-array/src/main/java/org/openapitools/client/model/MyExampleGet200Response.java
@@ -89,7 +89,7 @@ public void write(JsonWriter out, MyExampleGet200Response value) throws IOExcept
                     // check if the actual instance is of the type `List<@Valid OneOf1>`
                     if (value.getActualInstance() instanceof List<?>) {
                         List<?> list = (List<?>) value.getActualInstance();
-                        if (list.get(0) instanceof OneOf1) {
+                        if (!list.isEmpty() && list.get(0) instanceof OneOf1) {
                             JsonArray array = adapterListOneOf1.toJsonTree((List<@Valid OneOf1>)value.getActualInstance()).getAsJsonArray();
                             elementAdapter.write(out, array);
                             return;
@@ -191,7 +191,7 @@ public Map<String, Class<?>> getSchemas() {
     public void setActualInstance(Object instance) {
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof OneOf1) {
+            if (!list.isEmpty() && list.get(0) instanceof OneOf1) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/model/RefToRefParameterAnyofRefToAnyofParameter.java b/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/model/RefToRefParameterAnyofRefToAnyofParameter.java
@@ -187,7 +187,7 @@ public void setActualInstance(Object instance) {
 
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof String) {
+            if (!list.isEmpty() && list.get(0) instanceof String) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/ArrayAnyOf.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/ArrayAnyOf.java
@@ -182,7 +182,7 @@ public void setActualInstance(Object instance) {
 
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof String) {
+            if (!list.isEmpty() && list.get(0) instanceof String) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/ArrayOneOf.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/ArrayOneOf.java
@@ -187,7 +187,7 @@ public void setActualInstance(Object instance) {
 
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof String) {
+            if (!list.isEmpty() && list.get(0) instanceof String) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/FakeAnyOfWIthSameErasureGet200Response.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/FakeAnyOfWIthSameErasureGet200Response.java
@@ -157,7 +157,7 @@ public Map<String, Class<?>> getSchemas() {
     public void setActualInstance(Object instance) {
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof String) {
+            if (!list.isEmpty() && list.get(0) instanceof String) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/FakeOneOfWIthSameErasureGet200Response.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/FakeOneOfWIthSameErasureGet200Response.java
@@ -163,7 +163,7 @@ public Map<String, Class<?>> getSchemas() {
     public void setActualInstance(Object instance) {
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof String) {
+            if (!list.isEmpty() && list.get(0) instanceof String) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/Value.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/Value.java
@@ -86,7 +86,7 @@ public void write(JsonWriter out, Value value) throws IOException {
                     // check if the actual instance is of the type `List<Scalar>`
                     if (value.getActualInstance() instanceof List<?>) {
                         List<?> list = (List<?>) value.getActualInstance();
-                        if (list.get(0) instanceof Scalar) {
+                        if (!list.isEmpty() && list.get(0) instanceof Scalar) {
                             JsonArray array = adapterListScalar.toJsonTree((List<Scalar>)value.getActualInstance()).getAsJsonArray();
                             elementAdapter.write(out, array);
                             return;
@@ -187,7 +187,7 @@ public void setActualInstance(Object instance) {
 
         if (instance instanceof List<?>) {
             List<?> list = (List<?>) instance;
-            if (list.get(0) instanceof Scalar) {
+            if (!list.isEmpty() && list.get(0) instanceof Scalar) {
                 super.setActualInstance(instance);
                 return;
             }
diff --git a/samples/client/petstore/kotlin-model-prefix-type-mappings/src/main/kotlin/org/openapitools/client/models/ApiAnyOfUserOrPetOrArrayString.kt b/samples/client/petstore/kotlin-model-prefix-type-mappings/src/main/kotlin/org/openapitools/client/models/ApiAnyOfUserOrPetOrArrayString.kt
@@ -74,7 +74,7 @@ data class ApiAnyOfUserOrPetOrArrayString(var actualInstance: Any? = null) {
                     // check if the actual instance is of the type `kotlin.collections.List<kotlin.String>`
                     if (value.actualInstance is List<*>) {
                         val list = value.actualInstance as List<Any>
-                        if (list.get(0) is kotlin.String) {
+                        if (!list.isEmpty() && list.get(0) is kotlin.String) {
                             val array = adapterkotlincollectionsListkotlinString.toJsonTree(value.actualInstance as kotlin.collections.List<kotlin.String>?).getAsJsonArray()
                             elementAdapter.write(out, array)
                             return
diff --git a/samples/client/petstore/kotlin-model-prefix-type-mappings/src/main/kotlin/org/openapitools/client/models/ApiUserOrPetOrArrayString.kt b/samples/client/petstore/kotlin-model-prefix-type-mappings/src/main/kotlin/org/openapitools/client/models/ApiUserOrPetOrArrayString.kt
@@ -74,7 +74,7 @@ data class ApiUserOrPetOrArrayString(var actualInstance: Any? = null) {
                     // check if the actual instance is of the type `kotlin.collections.List<kotlin.String>`
                     if (value.actualInstance is List<*>) {
                         val list = value.actualInstance as List<Any>
-                        if (list.get(0) is kotlin.String) {
+                        if (!list.isEmpty() && list.get(0) is kotlin.String) {
                             val array = adapterkotlincollectionsListkotlinString.toJsonTree(value.actualInstance as kotlin.collections.List<kotlin.String>?).getAsJsonArray()
                             elementAdapter.write(out, array)
                             return

Original file line number	Diff line number	Diff line change
`@@ -187,7 +187,7 @@ public void setActualInstance(Object instance) {`
`187`	`187`
`188`	`188`	`if (instance instanceof List<?>) {`
`189`	`189`	`List<?> list = (List<?>) instance;`
`190`		`- if (list.get(0) instanceof String) {`
	`190`	`+ if (!list.isEmpty() && list.get(0) instanceof String) {`
`191`	`191`	`super.setActualInstance(instance);`
`192`	`192`	`return;`
`193`	`193`	`}`
Original file line number	Diff line number	Diff line change
`@@ -182,7 +182,7 @@ public void setActualInstance(Object instance) {`
`182`	`182`
`183`	`183`	`if (instance instanceof List<?>) {`
`184`	`184`	`List<?> list = (List<?>) instance;`
`185`		`- if (list.get(0) instanceof String) {`
	`185`	`+ if (!list.isEmpty() && list.get(0) instanceof String) {`
`186`	`186`	`super.setActualInstance(instance);`
`187`	`187`	`return;`
`188`	`188`	`}`
Original file line number	Diff line number	Diff line change
`@@ -157,7 +157,7 @@ public Map<String, Class<?>> getSchemas() {`
`157`	`157`	`public void setActualInstance(Object instance) {`
`158`	`158`	`if (instance instanceof List<?>) {`
`159`	`159`	`List<?> list = (List<?>) instance;`
`160`		`- if (list.get(0) instanceof String) {`
	`160`	`+ if (!list.isEmpty() && list.get(0) instanceof String) {`
`161`	`161`	`super.setActualInstance(instance);`
`162`	`162`	`return;`
`163`	`163`	`}`
Original file line number	Diff line number	Diff line change
`@@ -163,7 +163,7 @@ public Map<String, Class<?>> getSchemas() {`
`163`	`163`	`public void setActualInstance(Object instance) {`
`164`	`164`	`if (instance instanceof List<?>) {`
`165`	`165`	`List<?> list = (List<?>) instance;`
`166`		`- if (list.get(0) instanceof String) {`
	`166`	`+ if (!list.isEmpty() && list.get(0) instanceof String) {`
`167`	`167`	`super.setActualInstance(instance);`
`168`	`168`	`return;`
`169`	`169`	`}`