Surface psql list errors instead of reporting an empty workspace

cmd/psql/psql.go

@@ -181,7 +181,10 @@ For more information, see: https://docs.databricks.com/aws/en/oltp/
 		ctx := cmd.Context()
 		w := cmdctx.WorkspaceClient(ctx)
 
-		instances, projects := listAllDatabases(ctx, w)
+		instances, projects, err := listAllDatabases(ctx, w)
+		if err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
 
 		var names []string
 		for _, inst := range instances {
@@ -237,8 +240,10 @@ func parseResourcePath(input string) (project, branch, endpoint string, err erro
 }
 
 // listAllDatabases fetches all database instances and projects in parallel.
-// Errors are silently ignored; callers should check for empty results.
-func listAllDatabases(ctx context.Context, w *databricks.WorkspaceClient) ([]database.DatabaseInstance, []postgres.Project) {
+// A single failing call is tolerated because a workspace may have only one of
+// the two products enabled; an error is returned only when both calls fail,
+// so that e.g. an auth failure is not reported as an empty workspace.
+func listAllDatabases(ctx context.Context, w *databricks.WorkspaceClient) ([]database.DatabaseInstance, []postgres.Project, error) {
 	type result[T any] struct {
 		value []T
 		err   error
@@ -260,6 +265,10 @@ func listAllDatabases(ctx context.Context, w *databricks.WorkspaceClient) ([]dat
 	instResult := <-instancesCh
 	projResult := <-projectsCh
 
+	if instResult.err != nil && projResult.err != nil {
+		return nil, nil, errors.Join(instResult.err, projResult.err)
+	}
+
 	var instances []database.DatabaseInstance
 	var projects []postgres.Project
 	if instResult.err == nil {
@@ -269,7 +278,7 @@ func listAllDatabases(ctx context.Context, w *databricks.WorkspaceClient) ([]dat
 		projects = projResult.value
 	}
 
-	return instances, projects
+	return instances, projects, nil
 }
 
 // showSelectionAndConnect shows a combined dropdown of Lakebase databases.
@@ -278,8 +287,11 @@ func showSelectionAndConnect(ctx context.Context, retryConfig libpsql.RetryConfi
 
 	sp := cmdio.NewSpinner(ctx)
 	sp.Update("Loading Lakebase databases...")
-	instances, projects := listAllDatabases(ctx, w)
+	instances, projects, err := listAllDatabases(ctx, w)
 	sp.Close()
+	if err != nil {
+		return fmt.Errorf("failed to list Lakebase databases: %w", err)
+	}
 
 	if len(instances) == 0 && len(projects) == 0 {
 		return errors.New("no Lakebase databases found in workspace")

cmd/psql/psql_test.go

@@ -1,9 +1,14 @@
 package psql
 
 import (
+	"errors"
 	"testing"
 
+	"github.com/databricks/databricks-sdk-go/experimental/mocks"
+	"github.com/databricks/databricks-sdk-go/service/database"
+	"github.com/databricks/databricks-sdk-go/service/postgres"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -81,3 +86,74 @@ func TestParseResourcePath(t *testing.T) {
 		})
 	}
 }
+
+func TestListAllDatabases(t *testing.T) {
+	instErr := errors.New("instances list failed")
+	projErr := errors.New("projects list failed")
+	instances := []database.DatabaseInstance{{Name: "my-instance"}}
+	projects := []postgres.Project{{Name: "projects/my-project"}}
+
+	tests := []struct {
+		name          string
+		instErr       error
+		projErr       error
+		wantInstances []database.DatabaseInstance
+		wantProjects  []postgres.Project
+		wantErr       bool
+	}{
+		{
+			name:          "both succeed",
+			wantInstances: instances,
+			wantProjects:  projects,
+		},
+		{
+			name:         "instances call fails",
+			instErr:      instErr,
+			wantProjects: projects,
+		},
+		{
+			name:          "projects call fails",
+			projErr:       projErr,
+			wantInstances: instances,
+		},
+		{
+			name:    "both calls fail",
+			instErr: instErr,
+			projErr: projErr,
+			wantErr: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			m := mocks.NewMockWorkspaceClient(t)
+
+			var instReturn []database.DatabaseInstance
+			if tc.instErr == nil {
+				instReturn = instances
+			}
+			m.GetMockDatabaseAPI().EXPECT().
+				ListDatabaseInstancesAll(mock.Anything, database.ListDatabaseInstancesRequest{}).
+				Return(instReturn, tc.instErr)
+
+			var projReturn []postgres.Project
+			if tc.projErr == nil {
+				projReturn = projects
+			}
+			m.GetMockPostgresAPI().EXPECT().
+				ListProjectsAll(mock.Anything, postgres.ListProjectsRequest{}).
+				Return(projReturn, tc.projErr)
+
+			gotInstances, gotProjects, err := listAllDatabases(t.Context(), m.WorkspaceClient)
+			if tc.wantErr {
+				require.Error(t, err)
+				assert.ErrorIs(t, err, tc.instErr)
+				assert.ErrorIs(t, err, tc.projErr)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tc.wantInstances, gotInstances)
+			assert.Equal(t, tc.wantProjects, gotProjects)
+		})
+	}
+}