UserAgent regex broken in ScalaJS

[swoogles]

Describe the bug

This blows up when its referenced in the browser.

zio-http/zio-http/shared/src/main/scala/zio/http/Header.scala

Line 4151 in 28c9de1

private val completeRegex = s"""^(?i)([a-z0-9]+)(?:/([a-z0-9.]+))(.*)$$""".r

To Reproduce
On snapshot - 3.0.0-RC4+77-66867e7f-SNAPSHOT/

object Main extends ZIOAppDefault{
  def run =
    ZIO.succeed(Header.UserAgent)
}

[987Nabil]

Is this actually a zio http error? It seems like valid scala code is producing invalid js code. Is this a scalajs bug?

[jamesward]

Regex's that are used in both JS and the JVM, must be compatible with both. No way around there being two different Regex engines.

[987Nabil]

@jamesward that's my point. I as a lib dev should not make sure that my regex works for both. That should be the scala js compiler/transpiler

[jamesward]

I agree. But unfortunately I don't think Scala has any plans to write their own Regex engine. So the reality for now is that users have to write Regex that works on their target platforms.

[swoogles]

Related (Almost decade-old) thread-
scala-js/scala-js#997 (comment)

[987Nabil]

Okay 🙄 At least the issue is clear now.

One way around would be to not use regex at all for the header parsing but RichTextCodec

[russwyte]

Would zio-parser be a viable option? One possible win would be that it is invertible.

[987Nabil]

RichTextCodec is similar to zio parser and we would not have another dependency.

[jdegoes]

/bounty $250

[algora-pbc]

## 💎 $250 bounty • ZIO

### Steps to solve:
1. Start working: Comment /attempt #2707 with your implementation plan
2. Submit work: Create a pull request including /claim #2707 in the PR body to claim the bounty
3. Receive payment: 100% of the bounty is received 2-5 days post-reward. Make sure you are eligible for payouts

### Additional opportunities:
* 🔴 Livestream on Algora TV while solving this bounty & earn $200 upon merge! Make sure to have your camera and microphone on. Comment /livestream once live

Thank you for contributing to zio/zio-http!

Add a bounty • Share on socials

Attempt	Started (GMT+0)	Solution
🟢 @pablf	Jun 15, 2024, 12:24:20 AM	#2912

[pablf]

/attempt #2707

Algora profile	Completed bounties	Tech	Active attempts	Options
@pablf	24 ZIO bounties + 1 bounty from 1 project	Scala, Rust		Cancel attempt

[algora-pbc]

💡 @pablf submitted a pull request that claims the bounty. You can visit your bounty board to reward.

[algora-pbc]

🎉🎈 @pablf has been awarded $250! 🎈🎊

• Share on socials
• Give feedback