Allow referencing inputs in jobs.<job_id>.runs-on (#9950)

This PR is a follow-up to https://code.forgejo.org/forgejo/runner/pulls/1117. That PR has to be merged before this one can proceed.

The objective is to allow referencing the `inputs` context in `jobs.<job_id>.runs-on`. That enables users to enter a label in the Forgejo UI during `workflow_dispatch`.

Example:

```yaml
name: test
on:
  workflow_dispatch:
    inputs:
      image:
        required: true
        type: string

jobs:
  test:
    runs-on: ${{ inputs.image }}
    steps:
      - run: echo "Running on ${{ inputs.image }}"
```

Using `inputs` with reusable workflows does not work. I haven't changed `schedule_tasks.go` because the `schedule` trigger does not support `inputs`.

<!--start release-notes-assistant-->

## Release notes
<!--URL:https://codeberg.org/forgejo/forgejo-->
- Features
  - [PR](https://codeberg.org/forgejo/forgejo/pulls/9950): <!--number 9950 --><!--line 0 --><!--description QWxsb3cgcmVmZXJlbmNpbmcgaW5wdXRzIGluIGpvYnMuPGpvYl9pZD4ucnVucy1vbg==-->Allow referencing inputs in jobs.<job_id>.runs-on<!--description-->
<!--end release-notes-assistant-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/9950
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Andreas Ahlenstorf <andreas@ahlenstorf.ch>
Co-committed-by: Andreas Ahlenstorf <andreas@ahlenstorf.ch>

services/actions/workflows.go

@@ -155,7 +155,7 @@ func (entry *Workflow) Dispatch(ctx context.Context, inputGetter InputValueGette
 		}
 	}
 
-	jobs, err := jobParser(content, jobparser.WithVars(vars))
+	jobs, err := jobParser(content, jobparser.WithVars(vars), jobparser.WithInputs(inputsAny))
 	if err != nil {
 		return nil, nil, err
 	}

tests/integration/actions_job_test.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"reflect"
+	"strconv"
 	"testing"
 	"time"
 
@@ -478,6 +479,63 @@ jobs:
 	})
 }
 
+func TestActionsRunsOnInputsWorkflowDispatch(t *testing.T) {
+	if !setting.Database.Type.IsSQLite3() {
+		t.Skip()
+	}
+
+	onApplicationRun(t, func(t *testing.T, u *url.URL) {
+		user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+		session := loginUser(t, user2.Name)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository, auth_model.AccessTokenScopeWriteUser)
+
+		testRepository := createActionsTestRepo(t, token, "actions-runs-on-inputs-workflow-dispatch", false)
+
+		ubuntuRunner := newMockRunner()
+		ubuntuRunner.registerAsRepoRunner(t, user2.Name, testRepository.Name, "ubuntu-runner", []string{"ubuntu"})
+
+		windowsRunner := newMockRunner()
+		windowsRunner.registerAsRepoRunner(t, user2.Name, testRepository.Name, "windows-runner", []string{"windows"})
+
+		workflowPath := ".gitea/workflows/pull.yaml"
+		workflow := `name: Test runs-on with inputs
+on:
+  workflow_dispatch:
+    inputs:
+      image:
+        required: true
+        type: string
+
+jobs:
+  test:
+    runs-on: ${{ inputs.image }}
+    steps:
+      - run: echo "Running on ${{ inputs.image }}"
+`
+
+		options := getWorkflowCreateFileOptions(user2, testRepository.DefaultBranch, fmt.Sprintf("create %s", workflowPath), workflow)
+		createWorkflowFile(t, token, user2.Name, testRepository.Name, workflowPath, options)
+
+		url := fmt.Sprintf("/%s/%s/actions/manual", user2.Name, testRepository.Name)
+		request := NewRequestWithValues(t, "POST", url, map[string]string{
+			"inputs[image]": "windows",
+			"ref":           testRepository.DefaultBranch,
+			"workflow":      "pull.yaml",
+			"actor":         strconv.FormatInt(user2.ID, 10),
+		})
+		session.MakeRequest(t, request, http.StatusSeeOther)
+
+		assert.Nil(t, ubuntuRunner.maybeFetchTask(t))
+
+		task := windowsRunner.fetchTask(t)
+		actionTask := unittest.AssertExistsAndLoadBean(t, &actions_model.ActionTask{ID: task.Id})
+		actionRunJob := unittest.AssertExistsAndLoadBean(t, &actions_model.ActionRunJob{ID: actionTask.JobID})
+		run := unittest.AssertExistsAndLoadBean(t, &actions_model.ActionRun{ID: actionRunJob.RunID})
+
+		assert.Equal(t, "Test runs-on with inputs", run.Title)
+	})
+}
+
 func createActionsTestRepo(t *testing.T, authToken, repoName string, isPrivate bool) *api.Repository {
 	req := NewRequestWithJSON(t, "POST", "/api/v1/user/repos", &api.CreateRepoOption{
 		Name:          repoName,