Apache Pulsar fails to enable OpenID authentication in function worker when configured as specified in documentation

When following the documentation on enabling OpenID Connect authentication in the Function Worker, you are presented with the following error.

[jdk.internal.loader.ClassLoaders$AppClassLoader@659e0bfd] error Uncaught exception in thread main: Cannot construct instance of `java.util.HashSet` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID')

I'm not sure what value if any I've configured incorrectly to cause this, here is an example of my configuration in the functions_worker.yml file.

authenticationEnabled: true
authenticationProviders: "org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID"
properties:
  openIDAllowedTokenIssuers: "https://stg.some-website.com/"
  openIDAllowedAudiences: "https://some-website.com/maas, https://some-website.com/userinfo"
  openIDRoleClaim: "https://some-web.com/role"
  openIDAcceptedTimeLeewaySeconds: 0
  openIDCacheSize: 5
  openIDCacheRefreshAfterWriteSeconds: 64800
  openIDCacheExpirationSeconds: 86400
  openIDHttpConnectionTimeoutMillis: 10000
  openIDHttpReadTimeoutMillis: 10000
  openIDRequireIssuersUseHttps: true
  openIDFallbackDiscoveryMode: "DISABLED"

Here is the full stack trace

Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: 2023-07-06T22:47:15,473Z [jdk.internal.loader.ClassLoaders$AppClassLoader@659e0bfd] error Uncaught exception in thread main: Cannot construct instance of `java.util.HashSet` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID')
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at [Source: (File); line: 306, column: 26] (through reference chain: org.apache.pulsar.functions.worker.WorkerConfig["authenticationProviders"]) 
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `java.util.HashSet` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID')
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at [Source: (File); line: 306, column: 26] (through reference chain: org.apache.pulsar.functions.worker.WorkerConfig["authenticationProviders"]) 
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1728)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1353)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.std.StdDeserializer._deserializeFromString(StdDeserializer.java:311)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.handleNonArray(StringCollectionDeserializer.java:284)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:192)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:182)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.std.StringCollectionDeserializer.deserialize(StringCollectionDeserializer.java:25)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:314)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:177)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4674)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3494)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at org.apache.pulsar.functions.worker.WorkerConfig.load(WorkerConfig.java:776)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at org.apache.pulsar.broker.PulsarService.initializeWorkerConfigFromBrokerConfig(PulsarService.java:1840)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at org.apache.pulsar.PulsarBrokerStarter$BrokerStarter.<init>(PulsarBrokerStarter.java:194)
Jul 06 22:47:15 lin-0afa7c99.mstarext.com pulsar[6665]: at org.apache.pulsar.PulsarBrokerStarter.main(PulsarBrokerStarter.java:333)

The authenticationProviders parameter must be passed as a yaml list. Here is the correct input:

authenticationProviders: ["org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID"]

You can also input it this way:

authenticationProviders:
  - "org.apache.pulsar.broker.authentication.oidc.AuthenticationProviderOpenID"

Note that the error indicates this when it says:

> Cannot construct instance of java.util.HashSet

It is trying to create a set from the value of authenticationProviders.

Note: the docs were originally incorrect. I updated them here: https://github.com/apache/pulsar-site/pull/632.