Add automatic .serena/cache caching for workflows with Serena tool

.github/aw/actions-lock.json

@@ -100,7 +100,7 @@
       "version": "v5.6.0",
       "sha": "a26af69be951a213d495a4c3e4e4022e16d87065"
     },
-    "actions/upload-artifact@v4": {
+    "actions/upload-artifact@v4.6.2": {
       "repo": "actions/upload-artifact",
       "version": "v4.6.2",
       "sha": "ea165f8d65b6e75b540449e92b4886f43607fa02"

pkg/workflow/compiler_yaml_main_job.go

@@ -36,6 +36,9 @@ func (c *Compiler) generateMainJobSteps(yaml *strings.Builder, data *WorkflowDat
 		}
 	}
 
+	// Add Serena cache step if Serena tool is enabled
+	c.generateSerenaCacheStep(yaml, data, needsCheckout)
+
 	// Add checkout steps for repository imports
 	// Each repository import needs to be checked out into a temporary folder
 	// so the merge script can copy files from it

pkg/workflow/data/action_pins.json

@@ -100,7 +100,7 @@
       "version": "v5.6.0",
       "sha": "a26af69be951a213d495a4c3e4e4022e16d87065"
     },
-    "actions/upload-artifact@v4": {
+    "actions/upload-artifact@v4.6.2": {
       "repo": "actions/upload-artifact",
       "version": "v4.6.2",
       "sha": "ea165f8d65b6e75b540449e92b4886f43607fa02"

pkg/workflow/serena_cache.go

@@ -0,0 +1,58 @@
+package workflow
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/githubnext/gh-aw/pkg/logger"
+)
+
+var serenaCacheLog = logger.New("workflow:serena_cache")
+
+// isSerenaEnabled checks if the Serena tool is configured in the workflow
+func isSerenaEnabled(data *WorkflowData) bool {
+	if data == nil {
+		return false
+	}
+
+	// Check ParsedTools first (strongly-typed)
+	if data.ParsedTools != nil && data.ParsedTools.Serena != nil {
+		serenaCacheLog.Print("Serena tool detected via ParsedTools")
+		return true
+	}
+
+	// Fallback to Tools map for backward compatibility
+	if data.Tools != nil {
+		if _, exists := data.Tools["serena"]; exists {
+			serenaCacheLog.Print("Serena tool detected via Tools map")
+			return true
+		}
+	}
+
+	return false
+}
+
+// generateSerenaCacheStep adds a cache step for .serena/cache if Serena tool is enabled
+// The cache is configured to:
+// - Use path: .serena/cache
+// - Ignore if the folder doesn't exist (continue-on-error: true)
+// - Expire in 7 days (GitHub Actions default cache retention policy)
+// - Use "last cache wins" strategy (save-always: true)
+func (c *Compiler) generateSerenaCacheStep(yaml *strings.Builder, data *WorkflowData, needsCheckout bool) {
+	// Only add cache if Serena is enabled and checkout was performed
+	if !isSerenaEnabled(data) || !needsCheckout {
+		return
+	}
+
+	serenaCacheLog.Print("Generating Serena cache step")
+
+	yaml.WriteString("      - name: Cache Serena\n")
+	fmt.Fprintf(yaml, "        uses: %s\n", GetActionPin("actions/cache"))
+	yaml.WriteString("        continue-on-error: true\n")
+	yaml.WriteString("        with:\n")
+	yaml.WriteString("          path: .serena/cache\n")
+	yaml.WriteString("          key: serena-${{ runner.os }}-${{ github.run_id }}-${{ github.run_attempt }}\n")
+	yaml.WriteString("          restore-keys: |\n")
+	yaml.WriteString("            serena-${{ runner.os }}-\n")
+	yaml.WriteString("          save-always: true\n")
+}