fix: use artifact prefix in conclusion job and script step downloads for workflow_call context (#21011)

* Initial plan

* fix: use artifact prefix in conclusion and script step downloads for workflow_call context

In workflow_call-compiled lock files, the conclusion job was downloading the
agent artifact with an unprefixed name ('agent') while the upload step used
the per-invocation prefix ('${{ needs.activation.outputs.artifact_prefix }}agent').

This mismatch caused the download to miss, leaving GH_AW_AGENT_OUTPUT unset
and breaking downstream safe-output processing.

Fix: pass artifactPrefixExprForDownstreamJob(data) to buildAgentOutputDownloadSteps
in buildConclusionJob, buildGitHubScriptStep, and buildCustomActionStep.

Also adds two new tests:
- TestConclusionJobWorkflowCallArtifactPrefix: verifies prefixed artifact name in workflow_call context
- TestConclusionJobNonWorkflowCallNoArtifactPrefix: verifies no prefix in non-workflow_call context

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* fix: use agent-downstream artifact prefix in buildGitHubScriptStep and buildCustomActionStep

buildSafeOutputJob-based jobs (e.g. upload_assets) only depend on the agent job,
not the activation job. Using needs.activation.outputs.artifact_prefix in those
jobs would break workflow_call workflows since activation is not in their needs.

Use artifactPrefixExprForAgentDownstreamJob (needs.agent.outputs.artifact_prefix)
in buildGitHubScriptStep and buildCustomActionStep instead.

Also adds two tests verifying the correct prefix expression is used per context.

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: Peli de Halleux <pelikhan@users.noreply.github.com>

Author: Copilot

.github/workflows/smoke-workflow-call-with-inputs.lock.yml

@@ -60,8 +60,9 @@ func (c *Compiler) buildConclusionJob(data *WorkflowData, mainJobName string, sa
 		steps = append(steps, c.buildGitHubAppTokenMintStep(data.SafeOutputs.GitHubApp, permissions, appTokenFallbackRepo)...)
 	}
 
-	// Add artifact download steps once (shared by noop and conclusion steps)
-	steps = append(steps, buildAgentOutputDownloadSteps("")...)
+	// Add artifact download steps once (shared by noop and conclusion steps).
+	// In workflow_call context, use the per-invocation prefix to avoid artifact name clashes.
+	steps = append(steps, buildAgentOutputDownloadSteps(artifactPrefixExprForDownstreamJob(data))...)
 
 	// Add noop processing step if noop is configured
 	if data.SafeOutputs.NoOp != nil {

.github/workflows/smoke-workflow-call.lock.yml

@@ -914,3 +914,68 @@ func TestConclusionJobNoPushRepoMemoryResult(t *testing.T) {
 		t.Error("Expected conclusion job to NOT include GH_AW_PUSH_REPO_MEMORY_RESULT when repo-memory is not configured")
 	}
 }
+
+// TestConclusionJobWorkflowCallArtifactPrefix verifies that the conclusion job uses the
+// prefixed artifact name in workflow_call context to match the upload step.
+func TestConclusionJobWorkflowCallArtifactPrefix(t *testing.T) {
+	compiler := NewCompiler()
+
+	workflowData := &WorkflowData{
+		Name: "Test Workflow",
+		On:   "workflow_call",
+		SafeOutputs: &SafeOutputsConfig{
+			NoOp: &NoOpConfig{},
+		},
+	}
+
+	job, err := compiler.buildConclusionJob(workflowData, string(constants.AgentJobName), []string{})
+	if err != nil {
+		t.Fatalf("Failed to build conclusion job: %v", err)
+	}
+	if job == nil {
+		t.Fatal("Expected conclusion job to be created")
+	}
+
+	allSteps := strings.Join(job.Steps, "\n")
+
+	// In workflow_call context, the artifact download must use the prefixed name
+	// to match the upload step which uses needs.activation.outputs.artifact_prefix.
+	prefixedArtifactName := "${{ needs.activation.outputs.artifact_prefix }}agent"
+	if !strings.Contains(allSteps, prefixedArtifactName) {
+		t.Errorf("Expected conclusion job download step to use prefixed artifact name %q in workflow_call context, but it was not found.\nGenerated steps:\n%s", prefixedArtifactName, allSteps)
+	}
+
+	// Ensure the unprefixed artifact name is not used
+	if strings.Contains(allSteps, "name: agent\n") {
+		t.Errorf("Expected conclusion job NOT to use unprefixed artifact name 'agent' in workflow_call context.\nGenerated steps:\n%s", allSteps)
+	}
+}
+
+// TestConclusionJobNonWorkflowCallNoArtifactPrefix verifies that the conclusion job uses
+// the unprefixed artifact name for non-workflow_call workflows.
+func TestConclusionJobNonWorkflowCallNoArtifactPrefix(t *testing.T) {
+	compiler := NewCompiler()
+
+	workflowData := &WorkflowData{
+		Name: "Test Workflow",
+		On:   "issues",
+		SafeOutputs: &SafeOutputsConfig{
+			NoOp: &NoOpConfig{},
+		},
+	}
+
+	job, err := compiler.buildConclusionJob(workflowData, string(constants.AgentJobName), []string{})
+	if err != nil {
+		t.Fatalf("Failed to build conclusion job: %v", err)
+	}
+	if job == nil {
+		t.Fatal("Expected conclusion job to be created")
+	}
+
+	allSteps := strings.Join(job.Steps, "\n")
+
+	// In non-workflow_call context, the artifact download should use the plain (unprefixed) name.
+	if strings.Contains(allSteps, "needs.activation.outputs.artifact_prefix") {
+		t.Errorf("Expected conclusion job NOT to use artifact_prefix in non-workflow_call context.\nGenerated steps:\n%s", allSteps)
+	}
+}

pkg/workflow/notify_comment.go

@@ -682,3 +682,62 @@ func TestBuildGitHubScriptStepNoWorkingDirectory(t *testing.T) {
 		t.Error("Expected step to contain script")
 	}
 }
+
+// TestBuildGitHubScriptStepWorkflowCallArtifactPrefix verifies that agent artifact downloads
+// in buildGitHubScriptStep use needs.agent.outputs.artifact_prefix in workflow_call context.
+// These steps are used in jobs that depend on the agent job (not activation), so the
+// agent-downstream prefix expression must be used.
+func TestBuildGitHubScriptStepWorkflowCallArtifactPrefix(t *testing.T) {
+	compiler := &Compiler{}
+	workflowData := &WorkflowData{
+		Name: "Test Workflow",
+		On:   "workflow_call",
+	}
+
+	config := GitHubScriptStepConfig{
+		StepName:    "Test Step",
+		StepID:      "test_step",
+		MainJobName: "agent",
+		Script:      "console.log('test');",
+	}
+
+	steps := compiler.buildGitHubScriptStep(workflowData, config)
+	stepsStr := strings.Join(steps, "")
+
+	// In workflow_call context, the download must reference needs.agent (not needs.activation)
+	// because buildSafeOutputJob-based jobs depend on agent, not activation.
+	agentPrefix := "${{ needs.agent.outputs.artifact_prefix }}agent"
+	if !strings.Contains(stepsStr, agentPrefix) {
+		t.Errorf("Expected buildGitHubScriptStep to use %q in workflow_call context, but it was not found.\nGenerated steps:\n%s", agentPrefix, stepsStr)
+	}
+
+	// Ensure activation prefix is NOT used
+	if strings.Contains(stepsStr, "needs.activation.outputs.artifact_prefix") {
+		t.Errorf("Expected buildGitHubScriptStep NOT to use needs.activation.outputs.artifact_prefix (job does not depend on activation).\nGenerated steps:\n%s", stepsStr)
+	}
+}
+
+// TestBuildGitHubScriptStepNonWorkflowCallNoArtifactPrefix verifies no prefix is added
+// in non-workflow_call context.
+func TestBuildGitHubScriptStepNonWorkflowCallNoArtifactPrefix(t *testing.T) {
+	compiler := &Compiler{}
+	workflowData := &WorkflowData{
+		Name: "Test Workflow",
+		On:   "issues",
+	}
+
+	config := GitHubScriptStepConfig{
+		StepName:    "Test Step",
+		StepID:      "test_step",
+		MainJobName: "agent",
+		Script:      "console.log('test');",
+	}
+
+	steps := compiler.buildGitHubScriptStep(workflowData, config)
+	stepsStr := strings.Join(steps, "")
+
+	// In non-workflow_call context, no artifact prefix should be used
+	if strings.Contains(stepsStr, "artifact_prefix") {
+		t.Errorf("Expected buildGitHubScriptStep NOT to use artifact_prefix in non-workflow_call context.\nGenerated steps:\n%s", stepsStr)
+	}
+}

pkg/workflow/notify_comment_test.go

@@ -188,8 +188,11 @@ func (c *Compiler) buildCustomActionStep(data *WorkflowData, config GitHubScript
 		return c.buildGitHubScriptStep(data, config)
 	}
 
-	// Add artifact download steps before the custom action step
-	steps = append(steps, buildAgentOutputDownloadSteps("")...)
+	// Add artifact download steps before the custom action step.
+	// In workflow_call context, use the per-invocation prefix to avoid artifact name clashes.
+	// These steps are used in jobs that depend on the agent job (not activation), so use
+	// the agent-downstream prefix expression.
+	steps = append(steps, buildAgentOutputDownloadSteps(artifactPrefixExprForAgentDownstreamJob(data))...)
 
 	// Step name and metadata
 	steps = append(steps, fmt.Sprintf("      - name: %s\n", config.StepName))
@@ -287,8 +290,11 @@ func (c *Compiler) buildGitHubScriptStep(data *WorkflowData, config GitHubScript
 
 	var steps []string
 
-	// Add artifact download steps before the GitHub Script step
-	steps = append(steps, buildAgentOutputDownloadSteps("")...)
+	// Add artifact download steps before the GitHub Script step.
+	// In workflow_call context, use the per-invocation prefix to avoid artifact name clashes.
+	// These steps are used in jobs that depend on the agent job (not activation), so use
+	// the agent-downstream prefix expression.
+	steps = append(steps, buildAgentOutputDownloadSteps(artifactPrefixExprForAgentDownstreamJob(data))...)
 
 	// Step name and metadata
 	steps = append(steps, fmt.Sprintf("      - name: %s\n", config.StepName))