cue/cmd: unhandled task dependency detection

[verdverm]

What version of CUE are you using (cue version)?

v0.4.3-beta.1

Does this issue reproduce with the latest release?

yes: v0.4.2

What did you do?

The cue cmd resp case fails to detect the dependency

cue cmd body ./repro_tool.cue
cue cmd resp ./repro_tool.cue
cue cmd into ./repro_tool.cue

-- repro_tool.cue --
import "encoding/json"

apicall: {
  in: string
  r: { $id: "tool/file.Read", filename: in, contents: string }
  j: json.Unmarshal(r.contents)
  c: { 
    $id: "tool/http.Do"
    tls: verify: true
    method: j.method
    url: "\(j.host)\(j.path)"
    response: body: string
  }

  body: c.response.body
  resp: c.response
}

command: body: {
  call: apicall & { in: "req.json" }
  final: { $id: "tool/cli.Print", text: call.body }
}

command: resp: {
  call: apicall & { in: "req.json" }
  final: { $id: "tool/cli.Print", text: call.resp.body }
}

command: into: {
  call: apicall & { in: "req.json" }
  final: { $id: "tool/cli.Print", text: call.c.response.body }
}

What did you expect to see?

$ cue cmd resp ./dep_infer_001_tool.cue 
{"args":{},"headers":{"x-forwarded-proto":"https","x-forwarded-port":"443","host":"postman-echo.com","x-amzn-trace-id":"Root=1-623be975-50e5ee4a044b3bc6385bee82","accept-encoding":"gzip","user-agent":"Go-http-client/2.0"},"url":"https://postman-echo.com/get"}

What did you see instead?

$ cue cmd resp ./dep_infer_001_tool.cue 
command.resp.final.text: invalid string argument: non-concrete value string:
    ./dep_infer_001_tool.cue:26:3
    ./dep_infer_001_tool.cue:12:21
    ./dep_infer_001_tool.cue:26:35

in v0.4.2

$ cue cmd resp ./dep_infer_001_tool.cue 
command.resp.final.text: invalid string argument: non-concrete value string:
    ./dep_infer_001_tool.cue:26:3
    ./dep_infer_001_tool.cue:26:35

the error message has improved and increased accuracy! (in the beta)

[rogpeppe]

Thanks for the report.

For the record, call.body works, as does call.c.response.body, but call.resp.body does not. The issue description doesn't seem quite right to me, as dependencies from encoding/json are clearly being recognized in some of the cases here.

Here's a more complete and slightly slimmed down reproducer:

exec cue cmd resp ./repro_tool.cue

-- repro_tool.cue --
import "encoding/json"

apicall: {
  in: string
  r: { $id: "tool/file.Read", filename: in, contents: string }
  j: json.Unmarshal(r.contents)
  c: {
    $id: "tool/http.Do"
    tls: verify: true
    method: j.method
    url: "https://\(j.host)\(j.path)"
    response: body: string
  }
  resp: c.response
}

command: resp: {
  call: apicall & { in: "req.json" }
  final: { $id: "tool/cli.Print", text: call.resp.body }
}
-- req.json --
{
    "method": "GET",
    "host": "example.com",
    "path": "/"
}