command/exec: Fill ConsoleSize

This makes the exec'd process console dimensions immediately match the
users terminal.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

cli/command/container/exec.go

@@ -12,6 +12,7 @@ import (
 	"github.com/docker/cli/cli/config/configfile"
 	"github.com/docker/cli/opts"
 	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/versions"
 	apiclient "github.com/docker/docker/client"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -117,6 +118,14 @@ func RunExec(dockerCli command.Cli, options ExecOptions) error {
 		}
 	}
 
+	if execConfig.Tty {
+		// ConsoleSize is not supported before API 1.42
+		if versions.GreaterThanOrEqualTo(client.ClientVersion(), "1.42") {
+			height, width := dockerCli.Out().GetTtySize()
+			execConfig.ConsoleSize = &[2]uint{height, width}
+		}
+	}
+
 	response, err := client.ContainerExecCreate(ctx, options.Container, *execConfig)
 	if err != nil {
 		return err