WebTestClient.post MULTIPART_FORM_DATA causes reactor.blockhound.BlockingOperationError about blockhound

[oserohin]

Hello guys, any updates/suggestions about this issue?
Still present in SpringBoot 2.7.0 (Spring 5.3.20), Netty 4.1.77.Final and BlockHound 1.0.6.RELEASE

[pderop]

Hi @oserohin ,

We are back to maintenance of blockhound, sorry for the delay.

I have attached the reproducer demo.tgz project, to reproduce: "./gradlew test -i"

But I don't think it's a BlockHound issue. it's just that during the test, the HttpHandlerConnector schedules in the parallel scheduler the doConnect which ends up calling MimeTypeUtils. initRandom

and indeed, SecureRandom.next is a blocking operation. However, I see that the MimeTypeUtils.initRandom initializes the SecureRandom lazily (the method will call SecureRandom.next only one time, the first time initRandom will be called.

So, you can decide to either:

• from your junit tests, allow MimeTypeUtils.initRandom to block using a BlockHound integration plugin
• or during test initialization, call MimeTypeUtils.generateMultipartBoundary, this will force the initialization of the SecureRandom, so during your test, the method won't block while running within the parallel scheduler
• or if you think it's really an issue, then please report this to the spring-framework webflux team

if you don't mind, I will close this issue, feel free to reopen if needed; thanks.