cli/dump: more clearly inform the user upon tables with no visible columns

pkg/cli/cli.go

@@ -67,7 +67,15 @@ func Main() {
 
 	errCode := 0
 	if err := Run(os.Args[1:]); err != nil {
+		// Display the error and its details/hints.
+		fmt.Fprintln(stderr, "Error:", err.Error())
+		maybeShowErrorDetails(stderr, err, false /* printNewline */)
+
+		// Remind the user of which command was being run.
 		fmt.Fprintf(stderr, "Failed running %q\n", cmdName)
+
+		// Finally, extract the error code, as optionally specified
+		// by the sub-command.
 		errCode = 1
 		if ec, ok := errors.Cause(err).(*cliError); ok {
 			errCode = ec.exitCode
@@ -145,6 +153,10 @@ var cockroachCmd = &cobra.Command{
 	// Commands should manually print usage information when the error is,
 	// in fact, a result of a bad invocation, e.g. too many arguments.
 	SilenceUsage: true,
+	// Disable automatic printing of the error. We want to also print
+	// details and hints, which cobra does not do for us. Instead
+	// we do the printing in Main().
+	SilenceErrors: true,
 }
 
 func init() {

pkg/cli/cli_test.go

@@ -382,6 +382,7 @@ func (c cliTest) runWithArgsUnredirected(origArgs []string) {
 		return Run(args)
 	}(); err != nil {
 		fmt.Println(err)
+		maybeShowErrorDetails(os.Stdout, err, false /*printNewLine*/)
 	}
 }
 
@@ -1859,8 +1860,11 @@ Use "cockroach [command] --help" for more information about a command.
 				done <- err
 			}()
 
-			if err := Run(test.flags); err != nil && !test.expErr {
-				t.Error(err)
+			if err := Run(test.flags); err != nil {
+				fmt.Fprintln(w, "Error:", err)
+				if !test.expErr {
+					t.Error(err)
+				}
 			}
 
 			// back to normal state
@@ -2552,3 +2556,23 @@ func Example_sqlfmt() {
 	// sqlfmt --no-simplify -e select (1+2)+3
 	// SELECT (1 + 2) + 3
 }
+
+func Example_dump_no_visible_columns() {
+	c := newCLITest(cliTestParams{})
+	defer c.cleanup()
+
+	c.RunWithArgs([]string{"sql", "-e", "create table t(x int); set sql_safe_updates=false; alter table t drop x"})
+	c.RunWithArgs([]string{"dump", "defaultdb"})
+
+	// Output:
+	// sql -e create table t(x int); set sql_safe_updates=false; alter table t drop x
+	// ALTER TABLE
+	// dump defaultdb
+	// CREATE TABLE t (,
+	// 	FAMILY "primary" (rowid)
+	// );
+	// table "defaultdb.public.t" has no visible columns
+	// HINT: To proceed with the dump, either omit this table from the list of tables to dump, drop the table, or add some visible columns.
+	// --
+	// See: https://github.com/cockroachdb/cockroach/issues/37768
+}

pkg/cli/dump.go

@@ -29,7 +29,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/util/ctxgroup"
 	"github.com/cockroachdb/cockroach/pkg/util/timeofday"
 	"github.com/cockroachdb/cockroach/pkg/util/version"
-	"github.com/pkg/errors"
+	"github.com/cockroachdb/errors"
 	"github.com/spf13/cobra"
 )
 
@@ -538,6 +538,20 @@ func dumpTableData(w io.Writer, conn *sqlConn, clusterTS string, bmd basicMetada
 		return err
 	}
 
+	if strings.TrimSpace(md.columnNames) == "" {
+		// A table with no columns may still have one or more rows. In
+		// fact, it can have arbitrary many rows, each with a different
+		// (hidden) PK value. Unfortunately, the dump command today simply
+		// omits the hidden PKs from the dump, so it is not possible to
+		// restore the invisible values.
+		// Instead of failing with an incomprehensible error below, inform
+		// the user more clearly.
+		err := errors.Newf("table %q has no visible columns", tree.ErrString(bmd.name))
+		err = errors.WithHint(err, "To proceed with the dump, either omit this table from the list of tables to dump, drop the table, or add some visible columns.")
+		err = errors.WithIssueLink(err, errors.IssueLink{IssueURL: "https://github.com/cockroachdb/cockroach/issues/37768"})
+		return err
+	}
+
 	bs := fmt.Sprintf("SELECT %s FROM %s AS OF SYSTEM TIME %s ORDER BY PRIMARY KEY %[2]s",
 		md.columnNames,
 		md.name,