Add runtime support for Bun JavaScript runtime (#3876)

Author: Copilot

pkg/constants/constants.go

@@ -29,6 +29,9 @@ const DefaultGitHubMCPServerVersion = "v0.20.2"
 // DefaultFirewallVersion is the default version of the gh-aw-firewall (AWF) binary
 const DefaultFirewallVersion = "v0.1.1"
 
+// DefaultBunVersion is the default version of Bun for runtime setup
+const DefaultBunVersion = "1.1"
+
 // DefaultNodeVersion is the default version of Node.js for runtime setup
 const DefaultNodeVersion = "24"
 

pkg/workflow/action_pins_test.go

@@ -376,9 +376,9 @@ func TestApplyActionPinToStep(t *testing.T) {
 func TestGetActionPinsSorting(t *testing.T) {
 	pins := getActionPins()
 
-	// Verify we got all the pins (should be 16)
-	if len(pins) != 16 {
-		t.Errorf("getActionPins() returned %d pins, expected 16", len(pins))
+	// Verify we got all the pins (should be 17)
+	if len(pins) != 17 {
+		t.Errorf("getActionPins() returned %d pins, expected 17", len(pins))
 	}
 
 	// Verify they are sorted by version (descending) then by repository name (ascending)

pkg/workflow/data/action_pins.json

@@ -7,6 +7,11 @@
       "version": "v8",
       "sha": "ed597411d8f924073f98dfc5c65a23a2325f34cd"
     },
+    "oven-sh/setup-bun": {
+      "repo": "oven-sh/setup-bun",
+      "version": "v2",
+      "sha": "735343b667d3e6f658f44d0eca948eb6282f2b76"
+    },
     "actions/checkout": {
       "repo": "actions/checkout",
       "version": "v5",

pkg/workflow/runtime_setup.go

@@ -28,6 +28,15 @@ type RuntimeRequirement struct {
 
 // knownRuntimes is the list of all supported runtime configurations (alphabetically sorted by ID)
 var knownRuntimes = []*Runtime{
+	{
+		ID:             "bun",
+		Name:           "Bun",
+		ActionRepo:     "oven-sh/setup-bun",
+		ActionVersion:  "v2",
+		VersionField:   "bun-version",
+		DefaultVersion: constants.DefaultBunVersion,
+		Commands:       []string{"bun", "bunx"},
+	},
 	{
 		ID:             "dotnet",
 		Name:           ".NET",

pkg/workflow/runtime_setup_test.go

@@ -11,6 +11,16 @@ func TestDetectRuntimeFromCommand(t *testing.T) {
 		command  string
 		expected []string // Expected runtime IDs
 	}{
+		{
+			name:     "bun command",
+			command:  "bun install",
+			expected: []string{"bun"},
+		},
+		{
+			name:     "bunx command",
+			command:  "bunx tsc",
+			expected: []string{"bun"},
+		},
 		{
 			name:     "npm install command",
 			command:  "npm install",
@@ -257,6 +267,18 @@ func TestGenerateRuntimeSetupSteps(t *testing.T) {
 		expectSteps  int
 		checkContent []string
 	}{
+		{
+			name: "generates bun setup",
+			requirements: []RuntimeRequirement{
+				{Runtime: findRuntimeByID("bun"), Version: "1.1"},
+			},
+			expectSteps: 1,
+			checkContent: []string{
+				"Setup Bun",
+				"oven-sh/setup-bun@735343b667d3e6f658f44d0eca948eb6282f2b76",
+				"bun-version: '1.1'",
+			},
+		},
 		{
 			name: "generates node setup",
 			requirements: []RuntimeRequirement{