Describe the bug After updating from Boot 3.5.0. to 3.5.3 the property-based SAML configuration no longer works.

java.lang.IllegalArgumentException: entityId cannot be null or empty
    at org.springframework.util.Assert.hasText(Assert.java:253)
    at org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration$AssertingPartyDetails.<init>(RelyingPartyRegistration.java:489)
    at org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration$AssertingPartyDetails$Builder.build(RelyingPartyRegistration.java:847)
    at org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration$AssertingPartyDetails$Builder.build(RelyingPartyRegistration.java:666)
    at org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration$Builder.build(RelyingPartyRegistration.java:1126)
    at org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyRegistrationConfiguration.asRegistration(Saml2RelyingPartyRegistrationConfiguration.java:110)
    at org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyRegistrationConfiguration.asRegistration(Saml2RelyingPartyRegistrationConfiguration.java:78)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
    at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
    at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1939)
    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.AbstractPipeline.evaluate(AbstractPipeline.java:575)
    at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:260)
    at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:616)
    at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:622)
    at java.base/java.util.stream.ReferencePipeline.toList(ReferencePipeline.java:627)
    at org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyRegistrationConfiguration.relyingPartyRegistrationRepository(Saml2RelyingPartyRegistrationConfiguration.java:73)
...

To Reproduce

spring.security.saml2.relyingparty.registration:
  test.assertingparty.metadata-uri: classpath:saml/mock.xml

Expected behavior Asserting party metadata, including entityId, should be loaded from the metadata as in previous versions.

Comment From: OrangeDog

Actually the problem may be that Boot's autoconfiguration conditions changed and this only worked before because of my custom config. If so, please disregard,