fix: propagate sparse-checkout patterns and fetch-depth to safe_outputs checkout

pkg/workflow/compiler_safe_outputs_steps.go

@@ -47,8 +47,14 @@ func (c *Compiler) buildSharedPRCheckoutSteps(data *WorkflowData) []string {
 	consolidatedSafeOutputsStepsLog.Print("Building shared PR checkout steps")
 	var steps []string
 	fetchDepth := 1
+	var sparsePatterns []string
 
-	if defaultCheckout := NewCheckoutManager(data.CheckoutConfigs).GetDefaultCheckoutOverride(); defaultCheckout != nil && defaultCheckout.fetchDepth != nil {
+	// Build a single CheckoutManager so we can query both the default and cross-repo entries.
+	checkoutMgr := NewCheckoutManager(data.CheckoutConfigs)
+
+	// Same-repo fallback: use the default (workspace-root) checkout's fetch-depth.
+	// Overridden below for cross-repo targets once targetRepoSlug is known.
+	if defaultCheckout := checkoutMgr.GetDefaultCheckoutOverride(); defaultCheckout != nil && defaultCheckout.fetchDepth != nil {
 		fetchDepth = *defaultCheckout.fetchDepth
 		consolidatedSafeOutputsStepsLog.Printf("Using custom checkout fetch-depth for safe_outputs: %d", fetchDepth)
 	}
@@ -90,6 +96,24 @@ func (c *Compiler) buildSharedPRCheckoutSteps(data *WorkflowData) []string {
 		consolidatedSafeOutputsStepsLog.Printf("Using trialLogicalRepoSlug: %s", targetRepoSlug)
 	}
 
+	// For cross-repo targets, override fetch-depth and sparse-checkout patterns
+	// from the checkout: config entry that targets the same repository.  The agent
+	// job already uses these values; the safe_outputs job must mirror them so that
+	// (a) large repos are not checked out in full unnecessarily and (b) the working
+	// tree is consistent with what the agent operated on.
+	if targetRepoSlug != "" {
+		if targetEntry := checkoutMgr.GetCheckoutForRepository(targetRepoSlug); targetEntry != nil {
+			if targetEntry.fetchDepth != nil {
+				fetchDepth = *targetEntry.fetchDepth
+				consolidatedSafeOutputsStepsLog.Printf("Using checkout fetch-depth for cross-repo target %s: %d", targetRepoSlug, fetchDepth)
+			}
+			if len(targetEntry.sparsePatterns) > 0 {
+				sparsePatterns = targetEntry.sparsePatterns
+				consolidatedSafeOutputsStepsLog.Printf("Using %d sparse-checkout pattern(s) for cross-repo target %s", len(sparsePatterns), targetRepoSlug)
+			}
+		}
+	}
+
 	// Determine the ref (branch) to checkout
 	// Priority: create-pull-request base-branch > extracted base-branch from agent output > fallback expression
 	// This is critical: we must checkout the base branch, not github.sha (the triggering commit),
@@ -149,6 +173,12 @@ func (c *Compiler) buildSharedPRCheckoutSteps(data *WorkflowData) []string {
 		steps = append(steps, fmt.Sprintf("          token: %s\n", checkoutToken))
 		steps = append(steps, "          persist-credentials: false\n")
 		steps = append(steps, fmt.Sprintf("          fetch-depth: %d\n", fetchDepth))
+		if len(sparsePatterns) > 0 {
+			steps = append(steps, "          sparse-checkout: |\n")
+			for _, pattern := range sparsePatterns {
+				steps = append(steps, fmt.Sprintf("            %s\n", strings.TrimSpace(pattern)))
+			}
+		}
 	}
 
 	// Step 1b: Checkout repository with conditional execution
@@ -172,6 +202,12 @@ func (c *Compiler) buildSharedPRCheckoutSteps(data *WorkflowData) []string {
 	steps = append(steps, fmt.Sprintf("          token: %s\n", checkoutToken))
 	steps = append(steps, "          persist-credentials: false\n")
 	steps = append(steps, fmt.Sprintf("          fetch-depth: %d\n", fetchDepth))
+	if len(sparsePatterns) > 0 {
+		steps = append(steps, "          sparse-checkout: |\n")
+		for _, pattern := range sparsePatterns {
+			steps = append(steps, fmt.Sprintf("            %s\n", strings.TrimSpace(pattern)))
+		}
+	}
 
 	// Step 2: Configure Git credentials with conditional execution
 	// Security: Pass GitHub token through environment variable to prevent template injection
@@ -207,7 +243,6 @@ func (c *Compiler) buildSharedPRCheckoutSteps(data *WorkflowData) []string {
 	// Without this, applyBundleToBranch must fall back to per-SHA git fetch (prerequisite
 	// recovery), which requires uploadpack.allowReachableSHA1InWant on the server.
 	if targetRepoSlug != "" {
-		checkoutMgr := NewCheckoutManager(data.CheckoutConfigs)
 		if matchedEntry := checkoutMgr.GetCheckoutForRepository(targetRepoSlug); matchedEntry != nil && len(matchedEntry.fetchRefs) > 0 {
 			consolidatedSafeOutputsStepsLog.Printf("Adding fetch refs step for cross-repo target %s (%d refs)", targetRepoSlug, len(matchedEntry.fetchRefs))
 			if fetchStep := buildSafeOutputsFetchRefsStep(targetRepoSlug, checkoutToken, matchedEntry.fetchRefs, RenderCondition(condition)); fetchStep != "" {

pkg/workflow/compiler_safe_outputs_steps_test.go

@@ -406,6 +406,71 @@ func TestBuildSharedPRCheckoutSteps(t *testing.T) {
 				"contains(needs.agent.outputs.output_types, 'push_to_pull_request_branch')",
 			},
 		},
+		{
+			name: "cross-repo with sparse-checkout patterns propagates them to safe_outputs checkout",
+			safeOutputs: &SafeOutputsConfig{
+				CreatePullRequests: &CreatePullRequestsConfig{
+					BaseSafeOutputConfig: BaseSafeOutputConfig{
+						GitHubToken: "${{ secrets.CROSS_PAT }}",
+					},
+					TargetRepoSlug: "org/monorepo",
+					BaseBranch:     "main",
+				},
+			},
+			checkoutConfigs: []*CheckoutConfig{
+				{
+					Repository:     "org/monorepo",
+					SparseCheckout: ".github\nscripts\ntest",
+				},
+			},
+			checkContains: []string{
+				"sparse-checkout: |",
+				"            .github",
+				"            scripts",
+				"            test",
+			},
+		},
+		{
+			name: "cross-repo without sparse-checkout does not emit sparse-checkout block",
+			safeOutputs: &SafeOutputsConfig{
+				CreatePullRequests: &CreatePullRequestsConfig{
+					TargetRepoSlug: "org/full-repo",
+				},
+			},
+			checkoutConfigs: []*CheckoutConfig{
+				{
+					Repository: "org/full-repo",
+				},
+			},
+			checkNotContains: []string{
+				"sparse-checkout:",
+			},
+		},
+		{
+			name: "cross-repo fetch-depth is read from checkout config for target repo, not default override",
+			safeOutputs: &SafeOutputsConfig{
+				CreatePullRequests: &CreatePullRequestsConfig{
+					TargetRepoSlug: "org/target",
+				},
+			},
+			checkoutConfigs: []*CheckoutConfig{
+				{
+					// The "default" checkout (empty repo/path) has a different fetch-depth.
+					// The cross-repo entry's fetch-depth should win for the safe_outputs checkout.
+					FetchDepth: func() *int { d := 0; return &d }(),
+				},
+				{
+					Repository: "org/target",
+					FetchDepth: func() *int { d := 10; return &d }(),
+				},
+			},
+			checkContains: []string{
+				"fetch-depth: 10",
+			},
+			checkNotContains: []string{
+				"fetch-depth: 0",
+			},
+		},
 	}
 
 	for _, tt := range tests {