dap-debug not working in small project, while lsp-lens functions well.

[gkfabs]

Describe the bug
dap-debug not working in small project, while lsp-lens functions well.

To Reproduce
A minimal Main to reproduce would be

package com.fabien.test

object Main {

  val a = 0

  def main(args: Array[String]) = {
    println(s"a = ${a}")
    val b = a + 10
    println(s"b = ${b}")
  }
}

Expected behavior
I am expecting the same behaviour with lsp-lens and dap-debug

Logs
The error message I see when running dap-debug is

helm-M-x-execute-command: ‘workspace/executeCommand’ with ‘debug-adapter-start’ failed.

(error "Could not find folder for build targets: BuildTargetIdentifier [
  uri = \"file:///home/fabs/test?id=root\"
]")

[gkfabs]

I debug the lsp calls to metals.

In the case of lsp-lens which is working I have

    [Trace - 01:39:40 PM] Sending request 'workspace/executeCommand - (132)'.
Params: {
  "command": "debug-adapter-start",
  "arguments": [
    {
      "targets": [
        {
          "uri": "file:/home/fabs/test/?id=root"
        }
      ],
      "dataKind": "scala-main-class",
      "data": {
        "class": "com.fabien.test.SmallMain",
        "arguments": [],
        "jvmOptions": [
          "-Duser.dir=/home/fabs/test"
        ],
        "environmentVariables": [
          "SHELL=/bin/bash", .....
        ],
        "shellCommand": "/\"usr\"/\"lib\"/\"jvm\"/\"java-17-openjdk-amd64\"/\"bin\"/\"java\" \"-Duser.dir=/home/fabs/test\" -classpath \"/home/fabs/test/.metals/.tmp/classpath_BE22971E1A1B89048D68DDA762B603A7.jar\" com.fabien.test.SmallMain "
      }
    }
  ]
}

In the case of dap-debug which is not working, I have

[Trace - 01:45:22 PM] Sending request 'workspace/executeCommand - (149)'.
Params: {
  "command": "debug-adapter-start",
  "arguments": [
    {
      "data": {
        "type": "scala",
        "class": "<main.class>",
        "name": "Scala Main Class",
        "arguments": [],
        "jvmOptions": [],
        "environmentVariables": []
      },
      "dataKind": "scala-main-class",
      "targets": [
        {
          "uri": "file:///home/fabs/test?id=root"
        }
      ]
    }
  ]
}

[gkfabs]

Using this template

  (dap-register-debug-template
    "Scala Launch Main"
    (list :type "scala"
          :request "launch"
          :class "com.fabien.test.SmallMain"
          :name "Scala Launch Main"
          :arguments []
          :jvmOptions []
          ))

and applying this patch

$ diff lsp-metals.el lsp-metals.el~
795,798c795,797
<                                                       "file:"
<                                                       (or (lsp-workspace-root)
<                                                           (error "The debug provide can be called under project root"))
<                                                       "/?id="
---
>                                                       (lsp--path-to-uri (or (lsp-workspace-root)
>                                                                             (error "The debug provide can be called under project root")))
>                                                       "?id="

makes it works with dap-debug

[gkfabs]

Actually to make it work for any build target, I had to apply this patch

$ diff lsp-metals.el lsp-metals.el~
795,798c795,797
<                                                       "file:"
<                                                       (or (lsp-workspace-root)
<                                                           (error "The debug provide can be called under project root"))
<                                                       "/"
<                                                       (or
<                                                        (plist-get conf :buildTarget)
<                                                        "")
<                                                       "/?id="
---
>                                                       (lsp--path-to-uri (or (lsp-workspace-root)
>                                                                             (error "The debug provide can be called under project root")))
>                                                       "?id="