Discrepancies between cloud output commands #5813

Problem

k6 cloud run --local-execution behaves differently from k6 run --out cloud: it is seems to always create a GCk6 test run, even when K6_CLOUD_PUSH_REF_ID is set.

Details

Sample runs:

$ K6_CLOUD_PUSH_REF_ID=99999 K6_CLOUD_TOKEN=<...> k6 run --out cloud test.js 

         /\      Grafana   /‾‾/  
    /\  /  \     |\  __   /  /   
   /  \/    \    | |/ /  /   ‾‾\ 
  /          \   |   (  |  (‾)  |
 / __________ \  |_|\_\  \_____/ 


     execution: local
        script: test.js
        output: cloud (https://app.k6.io/runs/99999)
<...>

I don't think app.k6.io is correct here (another bug?), but at least K6_CLOUD_PUSH_REF_ID is being noticed properly.

$ K6_CLOUD_PUSH_REF_ID=99999 K6_CLOUD_TOKEN=<...> k6 cloud run --local-execution test.js 
WARN[0000] DEPRECATED: No stack specified. Consider setting a default stack via the `k6 cloud login` command or the `K6_CLOUD_STACK_ID` environment variable as this will become mandatory in the next major release. 

         /\      Grafana   /‾‾/  
    /\  /  \     |\  __   /  /   
   /  \/    \    | |/ /  /   ‾‾\ 
  /          \   |   (  |  (‾)  |
 / __________ \  |_|\_\  \_____/ 


     execution: local
        script: test.js
        output: cloud (https://<my stack>.grafana.net/a/k6-app/runs/7208258)

<...>

ERRO[0014] Failed to push metrics to the cloud           error="(400/E5) Authentication error - could not authenticate (with read-access) to project the resource belongs to." output=cloudv2

The test finishes locally but is not finalized on the Cloud: it waits for timeout there. It's not auth problem, because the same command and the same script is OK without K6_CLOUD_PUSH_REF_ID. So there is likely an internal mismatch of test run IDs.

LLM analysis on topic:

With k6 run --out cloud, K6_CLOUD_PUSH_REF_ID is respected in the cloud output's Start() method (internal/output/cloud/output.go:182-189): if PushRefID is valid, the output skips CreateTestRun and pushes metrics directly to the provided ref ID. It also skips finalization (output.go:290-291), deferring lifecycle management to the caller.

With k6 cloud run --local-execution, createCloudTest (internal/cmd/outputs_cloud.go:36) runs before the cloud output starts and unconditionally calls apiClient.CreateTestRun() (line 147) without checking K6_CLOUD_PUSH_REF_ID. This creates an orphaned test run every time.

The env var is bound via envconfig tag in cloudapi/config.go:41 and merged at config.go:136-137, so the config infrastructure already supports it — createCloudTest just doesn't use it.

This is blocking the move to the new command in k6-operator, issue.