[BUG] ZioHttpInterpreter: Route with literal path segment makes route with variable path segment unavailable

[wwbakker]

Tapir version: Works in tapir 1.10.10 and before, broken since tapir 1.10.11 and later

Describe the bug

Consider the following code:

//> using dep com.softwaremill.sttp.tapir::tapir-zio-http-server::1.10.10

import zio.*
import zio.http.*
import sttp.tapir.generic.auto.*
import sttp.tapir.ztapir.*
import sttp.tapir.*
import sttp.tapir.server.ziohttp.ZioHttpInterpreter

object TestServer extends ZIOAppDefault with Tapir:

  val ep1 = endpoint.get.in("base" / "type1" / "fixed").out(stringBody)
  val ep2 = endpoint.get.in("base" / path[String]("type") / "dynamic").out(stringBody)
  val app = ZioHttpInterpreter()
    .toHttp(
      List(
        ep1.zServerLogic(_ => ZIO.succeed("Fixed endpoint - tapir 1.10.10")),
        ep2.zServerLogic(_ => ZIO.succeed("Dynamic endpoint - tapir 1.10.10"))
      )
    )

  override def run =
    Server
      .serve(app)
        .provideSomeLayer[Scope](
          ZLayer.succeed(Server.Config.default.port(8060)) >>> Server.live
        )

If I call the endpoints, both work as expected:

GET http://localhost:8060/base/type1/fixed

HTTP/1.1 200 OK
content-length: 30
Content-Type: text/plain; charset=UTF-8
date: Mon, 19 Aug 2024 13:47:23 GMT

Fixed endpoint - tapir 1.10.10

Response code: 200 (OK); Time: 231ms (231 ms); Content length: 30 bytes (30 B)

GET http://localhost:8060/base/type1/dynamic

HTTP/1.1 200 OK
content-length: 32
Content-Type: text/plain; charset=UTF-8
date: Mon, 19 Aug 2024 13:47:46 GMT

Dynamic endpoint - tapir 1.10.10

Response code: 200 (OK); Time: 16ms (16 ms); Content length: 32 bytes (32 B)

---

If I do the same with a newer version (same code, just versions changed):

//> using dep com.softwaremill.sttp.tapir::tapir-zio-http-server::1.11.1

import zio.*
import zio.http.*
import sttp.tapir.generic.auto.*
import sttp.tapir.ztapir.*
import sttp.tapir.*
import sttp.tapir.server.ziohttp.ZioHttpInterpreter

object TestServer extends ZIOAppDefault with Tapir:

  val ep1 = endpoint.get.in("base" / "type1" / "fixed").out(stringBody)
  val ep2 = endpoint.get.in("base" / path[String]("type") / "dynamic").out(stringBody)
  val app = ZioHttpInterpreter()
    .toHttp(
      List(
        ep1.zServerLogic(_ => ZIO.succeed("Fixed endpoint - tapir 1.11.1")),
        ep2.zServerLogic(_ => ZIO.succeed("Dynamic endpoint - tapir 1.11.1"))
      )
    )

  override def run =
    Server
      .serve(app)
        .provideSomeLayer[Scope](
          ZLayer.succeed(Server.Config.default.port(8060)) >>> Server.live
        )

If I call the endpoints, only the first one works:

GET http://localhost:8060/base/type1/fixed

HTTP/1.1 200 OK
content-length: 29
Content-Type: text/plain; charset=UTF-8
date: Mon, 19 Aug 2024 13:49:31 GMT

Fixed endpoint - tapir 1.11.1

Response code: 200 (OK); Time: 209ms (209 ms); Content length: 29 bytes (29 B)

GET http://localhost:8060/base/type1/dynamic

HTTP/1.1 404 Not Found
warning: 199 ZIO HTTP "/base/type1/dynamic"
date: Mon, 19 Aug 2024 13:50:01 GMT
content-length: 0

<Response body is empty>

Response code: 404 (Not Found); Time: 11ms (11 ms); Content length: 0 bytes (0 B)

Additional information I also did some research into whether this might be a zio-http issue. I see however that when using tapir, the routing is done by ZioHttpInterpreter, instead of the routing code from zio-http itself.

The interesting/funny thing there is that zio-http has the same bug, but as far as I can tell it has never worked there. (https://github.com/zio/zio-http/issues/3036)

My best guess is that the issue was introduced in this PR: https://github.com/softwaremill/tapir/pull/3856

[felix-hedenstrom]

We've also observed this issue and it prevents us from upgrading beyond 1.10.10.

[felix-hedenstrom]

I ran your example with 1.11.3 and it works now. Must have been fixed at some point.

[wwbakker]

That's good news. Seems to be fixed specifically in 1.11.3, because 1.11.2 still fails. Possibly the 3.0.0 zio-http support?

I will check in a real project hopefully later today, and if that fixes it I'll close the ticket.

[adamw]

I added a test, passes (at least locally). Let me know if there would be any more problems

[wwbakker]

Works well now, thanks @adamw @felix-hedenstrom and the contributors to the 1.11.3!