AWS: client credentials provider NPE

Comienza en org.apache.iceberg.aws.AwsClientProperties#credentialsProvider e inspecciona el procesamiento de clientCredentialsProviderProperties antes de llamar a PropertyUtil.filterProperties. Reproduce el caso de un proveedor de credenciales personalizado sin endpoint de refresh y, después, verifica que el cliente de AWS pueda crearse sin la NullPointerException indicada; añade cobertura en las pruebas relevantes de propiedades de AWS.

Apache Iceberg version

1.11.0 (latest release)

Query engine

None

Please describe the bug 🐞

As of 1.11.0 (https://github.com/apache/iceberg/pull/15249), AwsClientProperties#credentialsProvider unconditionally does a clientCredentialsProviderProperties.put(VendedCredentialsProvider.URI, refreshCredentialsEndpoint) if "client.credentials-provider" is set; this may result in null being put into the properties map. Other similar code paths check first to make sure the value is not null or empty before putting the value.

This does not play well with custom credentials providers / org.apache.iceberg.aws.AwsClientProperties:

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:233)
	at java.base/java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:180)
	at java.base/java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
	at java.base/java.util.HashMap$EntrySpliterator.forEachRemaining(HashMap.java:1858)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
	at org.apache.iceberg.util.PropertyUtil.filterProperties(PropertyUtil.java:191)
	at org.apache.iceberg.aws.AwsClientProperties.<init>(AwsClientProperties.java:116)
	at io.deephaven.iceberg.util.DeephavenS3ClientCredentialsProvider.create(DeephavenS3ClientCredentialsProvider.java:29)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.apache.iceberg.common.DynMethods$UnboundMethod.invokeChecked(DynMethods.java:60)
	at org.apache.iceberg.common.DynMethods$UnboundMethod.invoke(DynMethods.java:73)
	at org.apache.iceberg.common.DynMethods$StaticMethod.invoke(DynMethods.java:186)
	at org.apache.iceberg.aws.AwsClientProperties.createCredentialsProvider(AwsClientProperties.java:314)
	at org.apache.iceberg.aws.AwsClientProperties.credentialsProvider(AwsClientProperties.java:296)
	at org.apache.iceberg.aws.AwsClientProperties.credentialsProvider(AwsClientProperties.java:218)
	at org.apache.iceberg.aws.s3.S3FileIOProperties.getCredentialsProvider(S3FileIOProperties.java:996)
	at org.apache.iceberg.aws.s3.S3FileIOProperties.applyCredentialConfigurations(S3FileIOProperties.java:985)
	at org.apache.iceberg.aws.AwsClientFactories$DefaultAwsClientFactory.lambda$s3$0(AwsClientFactories.java:116)
	at software.amazon.awssdk.utils.builder.SdkBuilder.applyMutation(SdkBuilder.java:61)
	at org.apache.iceberg.aws.AwsClientFactories$DefaultAwsClientFactory.s3(AwsClientFactories.java:115)
	at io.deephaven.iceberg.util.DeephavenAwsClientFactory.s3(DeephavenAwsClientFactory.java:49)

I'm unclear the exact semantics of nulls in property maps, and if this should be considered an upstream issue (ie, null should not be put in the map), or a downstream issue (AwsClientProperties should be tolerant of entries that have null values).

Willingness to contribute

• I can contribute a fix for this bug independently
• I would be willing to contribute a fix for this bug with guidance from the Iceberg community
• I cannot contribute a fix for this bug at this time