fix: improve apps deploy error when APP_NAME is missing

acceptance/apps/deploy/no-bundle-no-args/output.txt

@@ -1,3 +1,9 @@
-Error: accepts 1 arg(s), received 0
+Error: missing required argument: APP_NAME
+
+Usage: databricks apps deploy APP_NAME
+
+APP_NAME is the name of the Databricks app to operate on.
+Alternatively, run this command from a project directory containing
+databricks.yml to auto-detect the app name.
 
 Exit code: 1

cmd/apps/bundle_helpers.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -27,12 +29,71 @@ func makeArgsOptionalWithBundle(cmd *cobra.Command, usage string) {
 			return fmt.Errorf("accepts at most 1 arg(s), received %d", len(args))
 		}
 		if !hasBundleConfig() && len(args) != 1 {
-			return fmt.Errorf("accepts 1 arg(s), received %d", len(args))
+			return missingAppNameError(cmd)
 		}
 		return nil
 	}
 }
 
+// missingAppNameError returns an error message that explains what the positional
+// argument should be, and attempts to infer a suggestion from the local environment.
+// The full subcommand path (e.g. "databricks apps start") is rendered from cmd so
+// the usage line and "Did you mean?" hint match the verb the user actually ran.
+func missingAppNameError(cmd *cobra.Command) error {
+	hint := inferAppNameHint()
+	commandPath := "databricks apps <command>"
+	argName := "APP_NAME"
+	if cmd != nil {
+		if p := cmd.CommandPath(); p != "" {
+			commandPath = p
+		}
+		if name := positionalArgName(cmd.Use); name != "" {
+			argName = name
+		}
+	}
+	msg := fmt.Sprintf(`missing required argument: %s
+
+Usage: %s %s
+
+%s is the name of the Databricks app to operate on.
+Alternatively, run this command from a project directory containing
+databricks.yml to auto-detect the app name.`, argName, commandPath, argName, argName)
+
+	if hint != "" {
+		msg += fmt.Sprintf("\n\nDid you mean?\n  %s %s", commandPath, hint)
+	}
+
+	return errors.New(msg)
+}
+
+func positionalArgName(use string) string {
+	start := strings.Index(use, "[")
+	end := strings.Index(use, "]")
+	if start < 0 || end <= start {
+		return ""
+	}
+	return use[start+1 : end]
+}
+
+// inferAppNameHint tries to suggest an app name from the local environment.
+// Only returns a hint if the current directory looks like a Databricks app
+// (contains app.yml or app.yaml), using the directory name as the suggestion.
+func inferAppNameHint() string {
+	wd, err := os.Getwd()
+	if err != nil {
+		return ""
+	}
+
+	for _, filename := range []string{"app.yml", "app.yaml"} {
+		info, err := os.Stat(filepath.Join(wd, filename))
+		if err == nil && info.Mode().IsRegular() {
+			return filepath.Base(wd)
+		}
+	}
+
+	return ""
+}
+
 // getAppNameFromArgs returns the app name from args or detects it from the bundle.
 // Returns (appName, fromBundle, error).
 func getAppNameFromArgs(cmd *cobra.Command, args []string) (string, bool, error) {

cmd/apps/bundle_helpers_test.go

@@ -2,6 +2,8 @@ package apps
 
 import (
 	"errors"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/databricks/databricks-sdk-go/service/apps"
@@ -105,6 +107,112 @@ func TestFormatAppStatusMessage(t *testing.T) {
 	})
 }
 
+func TestInferAppNameHint(t *testing.T) {
+	t.Run("returns empty when no app config exists", func(t *testing.T) {
+		t.Chdir(t.TempDir())
+
+		assert.Equal(t, "", inferAppNameHint())
+	})
+
+	t.Run("returns dir name when app.yml exists", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		err := os.WriteFile(filepath.Join(dir, "app.yml"), []byte("command: [\"python\"]"), 0o644)
+		assert.NoError(t, err)
+
+		assert.Equal(t, filepath.Base(dir), inferAppNameHint())
+	})
+
+	t.Run("returns dir name when app.yaml exists", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		err := os.WriteFile(filepath.Join(dir, "app.yaml"), []byte("command: [\"python\"]"), 0o644)
+		assert.NoError(t, err)
+
+		assert.Equal(t, filepath.Base(dir), inferAppNameHint())
+	})
+
+	t.Run("returns empty when cwd has been deleted", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		os.Remove(dir)
+
+		assert.Equal(t, "", inferAppNameHint())
+	})
+}
+
+func TestMissingAppNameError(t *testing.T) {
+	t.Run("includes APP_NAME and usage info", func(t *testing.T) {
+		t.Chdir(t.TempDir())
+
+		err := missingAppNameError(nil)
+		assert.Contains(t, err.Error(), "APP_NAME")
+		assert.Contains(t, err.Error(), "databricks.yml")
+		assert.NotContains(t, err.Error(), "Did you mean")
+	})
+
+	t.Run("includes hint when app.yml exists", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		writeErr := os.WriteFile(filepath.Join(dir, "app.yml"), []byte("command: [\"python\"]"), 0o644)
+		assert.NoError(t, writeErr)
+
+		err := missingAppNameError(nil)
+		assert.Contains(t, err.Error(), "Did you mean")
+		assert.Contains(t, err.Error(), filepath.Base(dir))
+	})
+
+	t.Run("gracefully handles deleted cwd", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		os.Remove(dir)
+
+		err := missingAppNameError(nil)
+		assert.Contains(t, err.Error(), "APP_NAME")
+		assert.NotContains(t, err.Error(), "Did you mean")
+	})
+
+	t.Run("renders usage and hint from cmd path per verb", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		writeErr := os.WriteFile(filepath.Join(dir, "app.yml"), []byte("command: [\"python\"]"), 0o644)
+		assert.NoError(t, writeErr)
+
+		for _, tc := range []struct {
+			verb string
+			use  string
+			arg  string
+		}{
+			{"deploy", "deploy [APP_NAME]", "APP_NAME"},
+			{"start", "start [NAME]", "NAME"},
+			{"stop", "stop [NAME]", "NAME"},
+			{"delete", "delete [NAME]", "NAME"},
+		} {
+			t.Run(tc.verb, func(t *testing.T) {
+				root := &cobra.Command{Use: "databricks"}
+				apps := &cobra.Command{Use: "apps"}
+				sub := &cobra.Command{Use: tc.use}
+				root.AddCommand(apps)
+				apps.AddCommand(sub)
+
+				err := missingAppNameError(sub)
+				assert.Contains(t, err.Error(), "missing required argument: "+tc.arg)
+				assert.Contains(t, err.Error(), "Usage: databricks apps "+tc.verb+" "+tc.arg)
+				assert.Contains(t, err.Error(), "databricks apps "+tc.verb+" "+filepath.Base(dir))
+			})
+		}
+	})
+
+	t.Run("ignores non-regular app.yml entries", func(t *testing.T) {
+		dir := t.TempDir()
+		t.Chdir(dir)
+		assert.NoError(t, os.Mkdir(filepath.Join(dir, "app.yml"), 0o755))
+
+		err := missingAppNameError(nil)
+		assert.NotContains(t, err.Error(), "Did you mean")
+	})
+}
+
 func TestMakeArgsOptionalWithBundle(t *testing.T) {
 	t.Run("updates command usage", func(t *testing.T) {
 		cmd := &cobra.Command{}
@@ -117,6 +225,17 @@ func TestMakeArgsOptionalWithBundle(t *testing.T) {
 		makeArgsOptionalWithBundle(cmd, "test [NAME]")
 		assert.NotNil(t, cmd.Args)
 	})
+
+	t.Run("returns missing app name error when no bundle config exists", func(t *testing.T) {
+		t.Chdir(t.TempDir())
+
+		cmd := &cobra.Command{}
+		makeArgsOptionalWithBundle(cmd, "test [NAME]")
+
+		err := cmd.Args(cmd, nil)
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "missing required argument: NAME")
+	})
 }
 
 func TestGetAppNameFromArgs(t *testing.T) {

cmd/apps/logs.go

@@ -46,7 +46,6 @@ func newLogsCommand() *cobra.Command {
 	)
 
 	cmd := &cobra.Command{
-		Use:   "logs [NAME]",
 		Short: "Show Databricks app logs",
 		Long: `Show Databricks app logs.
 
@@ -78,15 +77,6 @@ Examples:
 
   # Mirror streamed logs to a local file while following for up to 5 minutes
   databricks apps logs my-app --follow --timeout 5m --output-file /tmp/my-app.log`,
-		Args: func(cmd *cobra.Command, args []string) error {
-			if len(args) > 1 {
-				return fmt.Errorf("accepts at most 1 arg(s), received %d", len(args))
-			}
-			if !hasBundleConfig() && len(args) != 1 {
-				return fmt.Errorf("accepts 1 arg(s), received %d", len(args))
-			}
-			return nil
-		},
 		PreRunE: root.MustWorkspaceClient,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			appName, fromBundle, err := getAppNameFromArgs(cmd, args)
@@ -207,6 +197,7 @@ Examples:
 			})
 		},
 	}
+	makeArgsOptionalWithBundle(cmd, "logs [NAME]")
 
 	streamGroup := cmdgroup.NewFlagGroup("Streaming")
 	streamGroup.FlagSet().IntVar(&tailLines, "tail-lines", defaultTailLines, "Number of recent log lines to show before streaming. Set to 0 to show everything.")

cmd/apps/logs_test.go

@@ -64,6 +64,17 @@ func TestBuildLogsURLRejectsUnknownScheme(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestLogsMissingNameError(t *testing.T) {
+	t.Chdir(t.TempDir())
+
+	cmd := newLogsCommand()
+	err := cmd.Args(cmd, nil)
+
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "missing required argument: NAME")
+	assert.Contains(t, err.Error(), "Usage: logs NAME")
+}
+
 func TestNormalizeOrigin(t *testing.T) {
 	assert.Equal(t, "https://example.com", normalizeOrigin("https://example.com/foo"))
 	assert.Equal(t, "http://example.com", normalizeOrigin("ws://example.com/foo"))