NPE for Map serializing

[cmdjulian]

Search before asking

• I searched in the issues and found nothing similar.
• I have confirmed that the same problem is not reproduced if I exclude the KotlinModule.
• I searched in the issues of databind and other modules used and found nothing similar.
• I have confirmed that the problem does not reproduce in Java and only occurs when using Kotlin and KotlinModule.

Describe the bug

Hey,

I found the following closed issue: FasterXML/jackson-databind#4878
I encounter the same issue, but only after upgrading from Jackson 2.18.4 to 2.19.0, downgrading to 2.18.4 fixes it.

This is my stack trace:

Exception in thread "main" java.lang.IllegalArgumentException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
	at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4663)
	at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:4594)
	at io.fabric8.kubernetes.client.utils.KubernetesSerialization.asYaml(KubernetesSerialization.java:237)
	at com.etalytics.etadeploy.render.KustomizeManifestRenderer.render(KustomizeManifestRenderer.kt:24)
	at com.etalytics.etadeploy.render.renderers.sealedsecrets.SealedSecretsManifestRenderer.render(SealedSecretsManifestRenderer.kt:77)
	at com.etalytics.etadeploy.render.KubernetesManifestRenderer$renderManifests$2$1.invokeSuspend(KubernetesManifestRenderer.kt:152)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:100)
	at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run(LimitedDispatcher.kt:124)
	at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:89)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:586)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:820)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:717)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:704)
	Suppressed: java.lang.IllegalArgumentException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4663)
		at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:4594)
		at io.fabric8.kubernetes.client.utils.KubernetesSerialization.asYaml(KubernetesSerialization.java:237)
		at com.etalytics.etadeploy.render.KustomizeManifestRenderer.render(KustomizeManifestRenderer.kt:24)
		at com.etalytics.etadeploy.render.renderers.traefik.TraefikManifestRenderer.render(TraefikManifestRenderer.kt:83)
		... 9 more
	Caused by: com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:400)
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:359)
		at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:324)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:810)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:763)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.getAndSerialize(AnyGetterWriter.java:81)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.serializeAsField(AnyGetterWriter.java:89)
		at io.fabric8.kubernetes.model.jackson.BeanPropertyWriterDelegate.serializeAsField(BeanPropertyWriterDelegate.java:68)
		at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:760)
		at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:183)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:503)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:342)
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4641)
		... 13 more
	Caused by: java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:796)
		... 22 more
	Suppressed: java.lang.IllegalArgumentException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["helmCharts"])
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4663)
		at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:4594)
		at io.fabric8.kubernetes.client.utils.KubernetesSerialization.asYaml(KubernetesSerialization.java:237)
		at com.etalytics.etadeploy.render.KustomizeManifestRenderer.render(KustomizeManifestRenderer.kt:24)
		at com.etalytics.etadeploy.render.renderers.monitoring.LocalMonitoringManifestRenderer.render(LocalMonitoringManifestRenderer.kt:236)
		at com.etalytics.etadeploy.render.renderers.monitoring.MonitoringManifestRenderer.render(MonitoringManifestRenderer.kt:49)
		... 9 more
	Caused by: com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["helmCharts"])
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:400)
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:359)
		at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:324)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:810)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:763)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.getAndSerialize(AnyGetterWriter.java:81)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.serializeAsField(AnyGetterWriter.java:89)
		at io.fabric8.kubernetes.model.jackson.BeanPropertyWriterDelegate.serializeAsField(BeanPropertyWriterDelegate.java:68)
		at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:760)
		at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:183)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:503)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:342)
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4641)
		... 14 more
	Caused by: java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:796)
		... 23 more
	Suppressed: java.lang.IllegalArgumentException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4663)
		at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:4594)
		at io.fabric8.kubernetes.client.utils.KubernetesSerialization.asYaml(KubernetesSerialization.java:237)
		at com.etalytics.etadeploy.render.KustomizeManifestRenderer.render(KustomizeManifestRenderer.kt:24)
		at com.etalytics.etadeploy.render.renderers.argocd.ArgoCdManifestRenderer.render(ArgoCdManifestRenderer.kt:245)
		... 9 more
	Caused by: com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:400)
		at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:359)
		at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:324)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:810)
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:763)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.getAndSerialize(AnyGetterWriter.java:81)
		at com.fasterxml.jackson.databind.ser.AnyGetterWriter.serializeAsField(AnyGetterWriter.java:89)
		at io.fabric8.kubernetes.model.jackson.BeanPropertyWriterDelegate.serializeAsField(BeanPropertyWriterDelegate.java:68)
		at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:760)
		at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:183)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:503)
		at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:342)
		at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4641)
		... 13 more
	Caused by: java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null
		at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:796)
		... 22 more
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null (through reference chain: com.etalytics.etadeploy.render.Kustomize["getAdditionalProperties"]->kotlin.collections.builders.MapBuilder["namespace"])
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:400)
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:359)
	at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:324)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:810)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:763)
	at com.fasterxml.jackson.databind.ser.AnyGetterWriter.getAndSerialize(AnyGetterWriter.java:81)
	at com.fasterxml.jackson.databind.ser.AnyGetterWriter.serializeAsField(AnyGetterWriter.java:89)
	at io.fabric8.kubernetes.model.jackson.BeanPropertyWriterDelegate.serializeAsField(BeanPropertyWriterDelegate.java:68)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:760)
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:183)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:503)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:342)
	at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:4641)
	... 13 more
Caused by: java.lang.NullPointerException: Cannot invoke "com.fasterxml.jackson.databind.JsonSerializer.serialize(Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)" because "keySerializer" is null
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:796)
	... 22 more

Any idea? I could also try to come up with a reproducer if it helps, as there already exists a very similar issue, I though it might not be needed though.

To Reproduce

// Your code here

Expected behavior

No NPE :D

Versions

Kotlin:
Jackson-module-kotlin: 2.19.0
Jackson-databind: 2.19.0

Additional context

No response

[k163377]

Please submit code that is minimally reproducible, as it cannot be investigated by only stack trace.
At least on CI, no problems have been detected.

[cowtowncoder]

Also note that stack trace here differs from one in FasterXML/jackson-databind#4878 so this is probably not via same code path.

Also: this may be the case already but make sure you use same minor version of jackson-module-kotlin and jackson-databind (both 2.19(.0)).