feat(install): auto-set global version when installing first version

src/cmd/install.go

@@ -70,6 +70,28 @@ func installSingle(runtimeName, version string) {
 	}
 
 	ui.Success("Successfully installed %s %s", provider.DisplayName(), version)
+
+	// Auto-set global version if no global version is currently configured
+	autoSetGlobalIfNeeded(provider, version)
+}
+
+// autoSetGlobalIfNeeded sets the installed version as global if no global version exists
+func autoSetGlobalIfNeeded(provider runtime.Provider, version string) {
+	currentGlobal, err := provider.GlobalVersion()
+	if err != nil || currentGlobal != "" {
+		// Either an error occurred or a global version is already set
+		ui.Debug("Global version check: current=%q, err=%v", currentGlobal, err)
+		return
+	}
+
+	// No global version configured, auto-set it
+	if err := provider.SetGlobalVersion(version); err != nil {
+		ui.Debug("Failed to auto-set global version: %v", err)
+		ui.Warning("Could not auto-set global version: %v", err)
+		return
+	}
+
+	ui.Info("Set as global version (first install)")
 }
 
 // installBulk installs all runtimes from .dtvem/runtimes.json
@@ -173,6 +195,8 @@ func executeInstalls(tasks []installTask) (success, failures int, failureList []
 		} else {
 			ui.Success("Installed %s %s", task.provider.DisplayName(), task.version)
 			success++
+			// Auto-set global version if needed
+			autoSetGlobalIfNeeded(task.provider, task.version)
 		}
 	}
 

src/cmd/install_test.go

@@ -0,0 +1,112 @@
+package cmd
+
+import (
+	"testing"
+
+	"github.com/dtvem/dtvem/src/internal/runtime"
+)
+
+// mockProvider implements runtime.Provider for testing
+type mockProvider struct {
+	name           string
+	displayName    string
+	globalVersion  string
+	globalSetError error
+	setGlobalCalls []string
+}
+
+func (m *mockProvider) Name() string                                          { return m.name }
+func (m *mockProvider) DisplayName() string                                   { return m.displayName }
+func (m *mockProvider) Shims() []string                                       { return []string{m.name} }
+func (m *mockProvider) ExecutablePath(version string) (string, error)         { return "", nil }
+func (m *mockProvider) IsInstalled(version string) (bool, error)              { return false, nil }
+func (m *mockProvider) ShouldReshimAfter(shimName string, args []string) bool { return false }
+func (m *mockProvider) Install(version string) error                          { return nil }
+func (m *mockProvider) Uninstall(version string) error                        { return nil }
+func (m *mockProvider) ListInstalled() ([]runtime.InstalledVersion, error) {
+	return nil, nil
+}
+func (m *mockProvider) ListAvailable() ([]runtime.AvailableVersion, error) {
+	return nil, nil
+}
+func (m *mockProvider) InstallPath(version string) (string, error) { return "", nil }
+func (m *mockProvider) LocalVersion() (string, error)              { return "", nil }
+func (m *mockProvider) SetLocalVersion(version string) error       { return nil }
+func (m *mockProvider) CurrentVersion() (string, error)            { return "", nil }
+func (m *mockProvider) DetectInstalled() ([]runtime.DetectedVersion, error) {
+	return nil, nil
+}
+func (m *mockProvider) GlobalPackages(installPath string) ([]string, error) {
+	return nil, nil
+}
+func (m *mockProvider) InstallGlobalPackages(version string, packages []string) error {
+	return nil
+}
+func (m *mockProvider) ManualPackageInstallCommand(packages []string) string {
+	return ""
+}
+
+func (m *mockProvider) GlobalVersion() (string, error) {
+	return m.globalVersion, nil
+}
+
+func (m *mockProvider) SetGlobalVersion(version string) error {
+	m.setGlobalCalls = append(m.setGlobalCalls, version)
+	return m.globalSetError
+}
+
+func TestAutoSetGlobalIfNeeded_NoGlobalVersion(t *testing.T) {
+	provider := &mockProvider{
+		name:          "test",
+		displayName:   "Test",
+		globalVersion: "", // No global version set
+	}
+
+	autoSetGlobalIfNeeded(provider, "1.0.0")
+
+	if len(provider.setGlobalCalls) != 1 {
+		t.Errorf("Expected SetGlobalVersion to be called once, got %d calls", len(provider.setGlobalCalls))
+	}
+	if len(provider.setGlobalCalls) > 0 && provider.setGlobalCalls[0] != "1.0.0" {
+		t.Errorf("Expected SetGlobalVersion called with '1.0.0', got %q", provider.setGlobalCalls[0])
+	}
+}
+
+func TestAutoSetGlobalIfNeeded_GlobalVersionAlreadySet(t *testing.T) {
+	provider := &mockProvider{
+		name:          "test",
+		displayName:   "Test",
+		globalVersion: "2.0.0", // Global version already set
+	}
+
+	autoSetGlobalIfNeeded(provider, "1.0.0")
+
+	if len(provider.setGlobalCalls) != 0 {
+		t.Errorf("Expected SetGlobalVersion to not be called when global already set, got %d calls", len(provider.setGlobalCalls))
+	}
+}
+
+func TestAutoSetGlobalIfNeeded_MultipleInstalls(t *testing.T) {
+	provider := &mockProvider{
+		name:          "test",
+		displayName:   "Test",
+		globalVersion: "", // No global version initially
+	}
+
+	// First install - should set global
+	autoSetGlobalIfNeeded(provider, "1.0.0")
+
+	if len(provider.setGlobalCalls) != 1 {
+		t.Fatalf("Expected first install to set global, got %d calls", len(provider.setGlobalCalls))
+	}
+
+	// Simulate that global is now set
+	provider.globalVersion = "1.0.0"
+
+	// Second install - should NOT change global
+	autoSetGlobalIfNeeded(provider, "2.0.0")
+
+	if len(provider.setGlobalCalls) != 1 {
+		t.Errorf("Expected second install to not change global, got %d calls total", len(provider.setGlobalCalls))
+	}
+}