feat: add version command

Author: imfing

cmd/diffs/main.go

@@ -4,15 +4,36 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"strings"
 	"time"
+
+	"github.com/spf13/cobra"
 )
 
 func main() {
-	if err := newRootCommand(time.Now()).Execute(); err != nil {
+	if err := executeRootCommand(newRootCommand(time.Now())); err != nil {
 		var quiet quietError
 		if !errors.As(err, &quiet) {
 			_, _ = fmt.Fprintln(os.Stderr, err)
 		}
 		os.Exit(1)
 	}
 }
+
+func executeRootCommand(cmd *cobra.Command) error {
+	err := cmd.Execute()
+	if err == nil || !isUnknownCommandError(err) {
+		return err
+	}
+
+	errOut := cmd.ErrOrStderr()
+	_, _ = fmt.Fprintln(errOut, err)
+	_, _ = fmt.Fprintln(errOut)
+	cmd.SetOut(errOut)
+	_ = cmd.Help()
+	return quietError{err: err}
+}
+
+func isUnknownCommandError(err error) bool {
+	return strings.HasPrefix(err.Error(), "unknown command ")
+}

cmd/diffs/main_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"net"
 	"os"
 	"os/exec"
@@ -143,6 +144,38 @@ func TestRootCommandRejectsDirectPRTarget(t *testing.T) {
 	}
 }
 
+func TestUnknownCommandPrintsRootHelp(t *testing.T) {
+	var out bytes.Buffer
+	cmd := newRootCommand(time.Time{})
+	cmd.SetOut(&bytes.Buffer{})
+	cmd.SetErr(&out)
+	cmd.SetArgs([]string{"bogus"})
+
+	err := executeRootCommand(cmd)
+	if err == nil {
+		t.Fatal("unknown command succeeded, want error")
+	}
+	var quiet quietError
+	if !errors.As(err, &quiet) {
+		t.Fatalf("error = %T, want quietError", err)
+	}
+
+	got := out.String()
+	for _, want := range []string{
+		`unknown command "bogus" for "diffs"`,
+		"Usage:",
+		"diffs [flags]",
+		"Available Commands:",
+		"local",
+		"pr",
+		"version",
+	} {
+		if !strings.Contains(got, want) {
+			t.Fatalf("unknown command output missing %q in:\n%s", want, got)
+		}
+	}
+}
+
 func TestLocalCommandRejectsNonGitRepository(t *testing.T) {
 	dir := t.TempDir()
 	var errOut bytes.Buffer
@@ -408,6 +441,7 @@ func TestRootCommandHelpShowsSubcommandsAndDir(t *testing.T) {
 		"diffs [flags]",
 		"local",
 		"pr",
+		"version",
 		"--dir string",
 	} {
 		if !strings.Contains(got, want) {
@@ -449,6 +483,21 @@ func TestPRCommandHelp(t *testing.T) {
 	}
 }
 
+func TestVersionCommandPrintsDefaultDevVersion(t *testing.T) {
+	var out bytes.Buffer
+	cmd := newRootCommand(time.Time{})
+	cmd.SetOut(&out)
+	cmd.SetErr(&bytes.Buffer{})
+	cmd.SetArgs([]string{"version"})
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("version failed: %v", err)
+	}
+
+	if got := out.String(); got != "dev\n" {
+		t.Fatalf("version output = %q, want %q", got, "dev\n")
+	}
+}
+
 func TestCommentsCommandAddAndListJSON(t *testing.T) {
 	dir := t.TempDir()
 	git(t, dir, "init", "-b", "main")

cmd/diffs/root.go

@@ -46,6 +46,7 @@ func newRootCommand(started time.Time) *cobra.Command {
 		newLocalCommand(opts, started),
 		newPRCommand(opts, started),
 		newCommentsCommand(opts),
+		newVersionCommand(),
 	)
 	return root
 }

cmd/diffs/version.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+var version = "dev"
+
+func newVersionCommand() *cobra.Command {
+	return &cobra.Command{
+		Use:   "version",
+		Short: "Print the diffs version",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			_, err := fmt.Fprintln(cmd.OutOrStdout(), version)
+			return err
+		},
+	}
+}