Wrap errors happening during PRS in a new vterrors code

go/vt/discovery/healthcheck.go

@@ -872,7 +872,7 @@ func (hc *HealthCheckImpl) TabletConnection(ctx context.Context, alias *topodata
 	hc.mu.Unlock()
 	if thc == nil || thc.Conn == nil {
 		// TODO: test that throws this error
-		return nil, vterrors.Errorf(vtrpc.Code_NOT_FOUND, "tablet: %v is either down or nonexistent", alias)
+		return nil, vterrors.VT15001(vtrpc.Code_NOT_FOUND, fmt.Sprintf("tablet: %v is either down or nonexistent", alias))
 	}
 	return thc.Connection(ctx), nil
 }

go/vt/vterrors/code.go

@@ -120,6 +120,8 @@ var (
 	VT14004 = errorWithoutState("VT14004", vtrpcpb.Code_UNAVAILABLE, "cannot find keyspace for: %s", "The specified keyspace could not be found.")
 	VT14005 = errorWithoutState("VT14005", vtrpcpb.Code_UNAVAILABLE, "cannot lookup sidecar database for keyspace: %s", "Failed to read sidecar database identifier.")
 
+	VT15001 = errorWithNoCode("VT15001", "session invalidated: close/reopen connection if applicable: %s", "This error means that the opened transaction should be closed by the application and re-opened.")
+
 	// Errors is a list of errors that must match all the variables
 	// defined above to enable auto-documentation of error codes.
 	Errors = []func(args ...any) *VitessError{
@@ -207,6 +209,10 @@ var (
 		VT14004,
 		VT14005,
 	}
+
+	ErrorsWithNoCode = []func(code vtrpcpb.Code, args ...any) *VitessError{
+		VT15001,
+	}
 )
 
 type VitessError struct {
@@ -258,3 +264,18 @@ func errorWithState(id string, code vtrpcpb.Code, state State, short, long strin
 		}
 	}
 }
+
+func errorWithNoCode(id string, short, long string) func(code vtrpcpb.Code, args ...any) *VitessError {
+	return func(code vtrpcpb.Code, args ...any) *VitessError {
+		s := short
+		if len(args) != 0 {
+			s = fmt.Sprintf(s, args...)
+		}
+
+		return &VitessError{
+			Err:         New(code, id+": "+s),
+			Description: long,
+			ID:          id,
+		}
+	}
+}

go/vt/vterrors/vterrorsgen/main.go

@@ -23,6 +23,7 @@ import (
 	"text/template"
 
 	"vitess.io/vitess/go/mysql/sqlerror"
+	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
 
 	"vitess.io/vitess/go/vt/vterrors"
 )
@@ -31,10 +32,14 @@ const (
 	tmpl = `
 | ID | Description | Error | MySQL Error Code | SQL State |
 | --- | --- | --- | --- | --- |
-{{- range $err := . }}
+{{- range $err := .Errors }}
 {{- $data := (call $err) }}
 | {{ $data.ID }} | {{ $data.Description }} | {{ FormatError $data.Err }} | {{ ConvertStateToMySQLErrorCode $data.State }} | {{ ConvertStateToMySQLState $data.State }} |
 {{- end }}
+{{- range $err := .ErrorsWithNoCode }}
+{{- $data := (call $err 0) }}
+| {{ $data.ID }} | {{ $data.Description }} | {{ FormatError $data.Err }} |  | {{ ConvertStateToMySQLState $data.State }} |
+{{- end }}
 `
 )
 
@@ -53,7 +58,16 @@ func main() {
 	})
 	t = template.Must(t.Parse(tmpl))
 
-	err := t.ExecuteTemplate(os.Stdout, "template", vterrors.Errors)
+	type data struct {
+		Errors           []func(args ...any) *vterrors.VitessError
+		ErrorsWithNoCode []func(code vtrpcpb.Code, args ...any) *vterrors.VitessError
+	}
+	d := data{
+		Errors:           vterrors.Errors,
+		ErrorsWithNoCode: vterrors.ErrorsWithNoCode,
+	}
+
+	err := t.ExecuteTemplate(os.Stdout, "template", d)
 	if err != nil {
 		log.Fatal(err)
 	}

go/vt/vttablet/grpctabletconn/conn.go

@@ -19,11 +19,15 @@ package grpctabletconn
 import (
 	"context"
 	"io"
+	"strings"
 	"sync"
 
 	"github.com/spf13/pflag"
 	"google.golang.org/grpc"
 
+	"vitess.io/vitess/go/vt/proto/vtrpc"
+	"vitess.io/vitess/go/vt/vterrors"
+
 	"vitess.io/vitess/go/netutil"
 	"vitess.io/vitess/go/sqltypes"
 	"vitess.io/vitess/go/vt/callerid"
@@ -132,7 +136,14 @@ func (conn *gRPCQueryClient) Execute(ctx context.Context, target *querypb.Target
 	}
 	er, err := conn.c.Execute(ctx, req)
 	if err != nil {
-		return nil, tabletconn.ErrorFromGRPC(err)
+		err = tabletconn.ErrorFromGRPC(err)
+		if err == nil {
+			return nil, nil
+		}
+		if vterrors.Code(err) == vtrpc.Code_UNAVAILABLE && strings.Contains(err.Error(), "connection refused") {
+			return nil, vterrors.VT15001(vtrpc.Code_UNAVAILABLE, err.Error())
+		}
+		return nil, err
 	}
 	return sqltypes.Proto3ToResult(er.Result), nil
 }

go/vt/vttablet/tabletserver/state_manager.go

@@ -436,7 +436,7 @@ func (sm *stateManager) verifyTargetLocked(ctx context.Context, target *querypb.
 					return nil
 				}
 			}
-			return vterrors.Errorf(vtrpcpb.Code_FAILED_PRECONDITION, "%s: %v, want: %v or %v", vterrors.WrongTablet, target.TabletType, sm.target.TabletType, sm.alsoAllow)
+			return vterrors.VT15001(vtrpcpb.Code_FAILED_PRECONDITION, fmt.Sprintf("%s: %v, want: %v or %v", vterrors.WrongTablet, target.TabletType, sm.target.TabletType, sm.alsoAllow))
 		}
 	} else {
 		if !tabletenv.IsLocalContext(ctx) {