Refactor extension executable error handling

pkg/cmd/extension/command.go

@@ -340,9 +340,11 @@ func NewCmdExtension(f *cmdutil.Factory) *cobra.Command {
 						}
 
 						err = m.InstallLocal(wd)
-						if errors.Is(err, ErrExtensionExecutableNotFound) {
+						var ErrExtensionExecutableNotFound *ErrExtensionExecutableNotFound
+						if errors.As(err, &ErrExtensionExecutableNotFound) {
+							cs := io.ColorScheme()
 							if io.IsStdoutTTY() {
-								fmt.Fprintln(io.ErrOut, err.Error())
+								fmt.Fprintf(io.ErrOut, "%s %s", cs.WarningIcon(), ErrExtensionExecutableNotFound.Error())
 							}
 							return nil
 						}

pkg/cmd/extension/command_test.go

@@ -287,27 +287,38 @@ func TestNewCmdExtension(t *testing.T) {
 			},
 		},
 		{
-			name: "install local extension without executable TTY",
+			name: "installing local extension without executable with TTY shows warning",
 			args: []string{"install", "."},
 			managerStubs: func(em *extensions.ExtensionManagerMock) func(*testing.T) {
 				em.InstallLocalFunc = func(dir string) error {
-					return ErrExtensionExecutableNotFound
+					return &ErrExtensionExecutableNotFound{
+						Dir:  tempDir,
+						Name: "gh-test",
+					}
 				}
 				em.ListFunc = func() []extensions.Extension {
 					return []extensions.Extension{}
 				}
 				return nil
 			},
-			wantStderr: fmt.Sprintln(ErrExtensionExecutableNotFound.Error()),
-			wantErr:    false,
-			isTTY:      true,
+			wantStderr: fmt.Sprintf(
+				"! %s",
+				(&ErrExtensionExecutableNotFound{
+					Dir:  tempDir,
+					Name: "gh-test",
+				}).Error()),
+			wantErr: false,
+			isTTY:   true,
 		},
 		{
-			name: "install local extension without executable no TTY",
+			name: "install local extension without executable with no TTY shows no warning",
 			args: []string{"install", "."},
 			managerStubs: func(em *extensions.ExtensionManagerMock) func(*testing.T) {
 				em.InstallLocalFunc = func(dir string) error {
-					return ErrExtensionExecutableNotFound
+					return &ErrExtensionExecutableNotFound{
+						Dir:  tempDir,
+						Name: "gh-test",
+					}
 				}
 				em.ListFunc = func() []extensions.Extension {
 					return []extensions.Extension{}

pkg/cmd/extension/manager.go

@@ -28,7 +28,15 @@ import (
 
 // ErrInitialCommitFailed indicates the initial commit when making a new extension failed.
 var ErrInitialCommitFailed = errors.New("initial commit failed")
-var ErrExtensionExecutableNotFound = errors.New("an extension has been installed but there is no executable")
+
+type ErrExtensionExecutableNotFound struct {
+	Dir  string
+	Name string
+}
+
+func (e *ErrExtensionExecutableNotFound) Error() string {
+	return fmt.Sprintf("an extension has been installed but there is no executable: executable file named \"%s\" in %s is required to run the extension after install. Perhaps you need to build it?\n", e.Name, e.Dir)
+}
 
 const darwinAmd64 = "darwin-amd64"
 
@@ -195,7 +203,6 @@ func (m *Manager) populateLatestVersions(exts []*Extension) {
 func (m *Manager) InstallLocal(dir string) error {
 	name := filepath.Base(dir)
 	targetLink := filepath.Join(m.installDir(), name)
-	cs := m.io.ColorScheme()
 
 	if err := os.MkdirAll(filepath.Dir(targetLink), 0755); err != nil {
 		return err
@@ -209,8 +216,10 @@ func (m *Manager) InstallLocal(dir string) error {
 	// it does indicate that the user will not be able to run the extension until
 	// the executable file is built or created manually somehow.
 	if _, err := os.Stat(filepath.Join(dir, name)); os.IsNotExist(err) {
-		errMsg := fmt.Errorf("%v %w: executable file named \"%s\" in %s is required to run the extension after install. Perhaps you need to build it?", cs.WarningIcon(), ErrExtensionExecutableNotFound, name, dir)
-		return errMsg
+		return &ErrExtensionExecutableNotFound{
+			Dir:  dir,
+			Name: name,
+		}
 	}
 	return nil
 }

pkg/cmd/extension/manager_test.go

@@ -771,7 +771,7 @@ func TestManager_Install_local_no_executable_found(t *testing.T) {
 	// to simulate an attempt to install a local extension without an executable
 
 	err := m.InstallLocal(localDir)
-	require.ErrorIs(t, err, ErrExtensionExecutableNotFound)
+	require.ErrorAs(t, err, new(*ErrExtensionExecutableNotFound))
 	assert.Equal(t, "", stdout.String())
 	assert.Equal(t, "", stderr.String())
 }