RequestFileTooLargeError is not raised with streams even though fileSize limit is set

[svsool]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.4.0

Plugin version

7.1.0

Node.js version

18.0.0

Operating system

macOS

Operating system version (i.e. 20.04, 11.3, 10)

12.3

Description

Thanks for this plugin.

I use @fastify/multipart for image upload and noticed that RequestFileTooLargeError is not raised with file streams in production env.

Here is the test in the current codebase that supposed to test that this error raised and it's raised with in-memory random buffer not bound to disk IO delays.

Although if one replaces randomFileBuffer with real stream fs.createReadStream('/tmp/images/15mb.jpeg') bigger than fileSize test starts to fail, but it expected to pass.

It's not obvious to me why error is not propagated in this case or should it at all.

Steps to Reproduce

Replace randomFileBuffer with fs.createReadStream('/tmp/images/15mb.jpeg') in this test.

Expected Behavior

I expect that RequestFileTooLargeError would be raised when read stream supplied.

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.