fix: update output handling for reusable workflows (#1521)

* fix: map job output for reusable workflows

This fixes the job outputs for reusable workflows. There is
a required indirection. Before this we took the outputs from
all jobs which is not what users express with the workflow
outputs.

* fix: remove double evaluation

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/exprparser/interpreter.go

@@ -15,6 +15,7 @@ type EvaluationEnvironment struct {
 	Github   *model.GithubContext
 	Env      map[string]string
 	Job      *model.JobContext
+	Jobs     *map[string]*model.WorkflowCallResult
 	Steps    map[string]*model.StepResult
 	Runner   map[string]interface{}
 	Secrets  map[string]string
@@ -155,6 +156,11 @@ func (impl *interperterImpl) evaluateVariable(variableNode *actionlint.VariableN
 		return impl.env.Env, nil
 	case "job":
 		return impl.env.Job, nil
+	case "jobs":
+		if impl.env.Jobs == nil {
+			return nil, fmt.Errorf("Unavailable context: jobs")
+		}
+		return impl.env.Jobs, nil
 	case "steps":
 		return impl.env.Steps, nil
 	case "runner":

pkg/model/workflow.go

@@ -117,6 +117,10 @@ type WorkflowCall struct {
 	Outputs map[string]WorkflowCallOutput `yaml:"outputs"`
 }
 
+type WorkflowCallResult struct {
+	Outputs map[string]string
+}
+
 func (w *Workflow) WorkflowCallConfig() *WorkflowCall {
 	if w.RawOn.Kind != yaml.MappingNode {
 		return nil

pkg/runner/expression.go

@@ -25,6 +25,8 @@ func (rc *RunContext) NewExpressionEvaluator(ctx context.Context) ExpressionEval
 }
 
 func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map[string]string) ExpressionEvaluator {
+	var workflowCallResult map[string]*model.WorkflowCallResult
+
 	// todo: cleanup EvaluationEnvironment creation
 	using := make(map[string]exprparser.Needs)
 	strategy := make(map[string]interface{})
@@ -44,6 +46,23 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 				Result:  jobs[needs].Result,
 			}
 		}
+
+		// only setup jobs context in case of workflow_call
+		// and existing expression evaluator (this means, jobs are at
+		// least ready to run)
+		if rc.caller != nil && rc.ExprEval != nil {
+			workflowCallResult = map[string]*model.WorkflowCallResult{}
+
+			for jobName, job := range jobs {
+				result := model.WorkflowCallResult{
+					Outputs: map[string]string{},
+				}
+				for k, v := range job.Outputs {
+					result.Outputs[k] = v
+				}
+				workflowCallResult[jobName] = &result
+			}
+		}
 	}
 
 	ghc := rc.getGithubContext(ctx)
@@ -53,6 +72,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 		Github: ghc,
 		Env:    env,
 		Job:    rc.getJobContext(),
+		Jobs:   &workflowCallResult,
 		// todo: should be unavailable
 		// but required to interpolate/evaluate the step outputs on the job
 		Steps:    rc.getStepsContext(),

pkg/runner/job_executor.go

@@ -162,8 +162,9 @@ func setJobOutputs(ctx context.Context, rc *RunContext) {
 		callerOutputs := make(map[string]string)
 
 		ee := rc.NewExpressionEvaluator(ctx)
-		for k, v := range rc.Run.Job().Outputs {
-			callerOutputs[k] = ee.Interpolate(ctx, v)
+
+		for k, v := range rc.Run.Workflow.WorkflowCallConfig().Outputs {
+			callerOutputs[k] = ee.Interpolate(ctx, ee.Interpolate(ctx, v.Value))
 		}
 
 		rc.caller.runContext.Run.Job().Outputs = callerOutputs

pkg/runner/testdata/.github/workflows/local-reusable-workflow.yml

@@ -27,7 +27,7 @@ on:
     outputs:
       output:
         description: "A workflow output"
-        value: ${{ jobs.reusable_workflow_job.outputs.output }}
+        value: ${{ jobs.reusable_workflow_job.outputs.job-output }}
 
 jobs:
   reusable_workflow_job:
@@ -79,4 +79,4 @@ jobs:
         echo "value=${{ inputs.string_required }}" >> $GITHUB_OUTPUT
 
     outputs:
-      output: ${{ steps.output_test.outputs.value }}
+      job-output: ${{ steps.output_test.outputs.value }}