oauth2Login() AuthenticationProvider's preserve root cause exception when rethrown

Closes gh-10228

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/authentication/OAuth2LoginAuthenticationProvider.java

@@ -110,7 +110,7 @@ public class OAuth2LoginAuthenticationProvider implements AuthenticationProvider
 		}
 		catch (OAuth2AuthorizationException ex) {
 			OAuth2Error oauth2Error = ex.getError();
-			throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString());
+			throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString(), ex);
 		}
 		OAuth2AccessToken accessToken = authorizationCodeAuthenticationToken.getAccessToken();
 		Map<String, Object> additionalParameters = authorizationCodeAuthenticationToken.getAdditionalParameters();

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/authentication/OAuth2LoginReactiveAuthenticationManager.java

@@ -99,7 +99,7 @@ public class OAuth2LoginReactiveAuthenticationManager implements ReactiveAuthent
 			}
 			return this.authorizationCodeManager.authenticate(token)
 					.onErrorMap(OAuth2AuthorizationException.class,
-							(e) -> new OAuth2AuthenticationException(e.getError(), e.getError().toString()))
+							(e) -> new OAuth2AuthenticationException(e.getError(), e.getError().toString(), e))
 					.cast(OAuth2AuthorizationCodeAuthenticationToken.class).flatMap(this::onSuccess);
 		});
 	}

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/authentication/OidcAuthorizationCodeAuthenticationProvider.java

@@ -173,7 +173,7 @@ public class OidcAuthorizationCodeAuthenticationProvider implements Authenticati
 		}
 		catch (OAuth2AuthorizationException ex) {
 			OAuth2Error oauth2Error = ex.getError();
-			throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString());
+			throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString(), ex);
 		}
 	}
 

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/authentication/OidcAuthorizationCodeReactiveAuthenticationManager.java

@@ -142,7 +142,7 @@ public class OidcAuthorizationCodeReactiveAuthenticationManager implements React
 			return this.accessTokenResponseClient.getTokenResponse(authzRequest).flatMap(
 					(accessTokenResponse) -> authenticationResult(authorizationCodeAuthentication, accessTokenResponse))
 					.onErrorMap(OAuth2AuthorizationException.class,
-							(e) -> new OAuth2AuthenticationException(e.getError(), e.getError().toString()))
+							(e) -> new OAuth2AuthenticationException(e.getError(), e.getError().toString(), e))
 					.onErrorMap(JwtException.class, (e) -> {
 						OAuth2Error invalidIdTokenError = new OAuth2Error(INVALID_ID_TOKEN_ERROR_CODE, e.getMessage(),
 								null);