@@ -307,7 +307,11 @@ func (cli *Client) ClientVersion() string {

 // added (1.24).

 func (cli *Client) NegotiateAPIVersion(ctx context.Context) {

 	if !cli.manualOverride {

-		ping, _ := cli.Ping(ctx)

+		ping, err := cli.Ping(ctx)

+		if err != nil {

+			// FIXME(thaJeztah): Ping returns an error when failing to connect to the API; we should not swallow the error here, and instead returning it.

+			return

+		}

 		cli.negotiateAPIVersionPing(ping)

 	}

 }

@@ -354,6 +354,19 @@ func TestNegotiateAPVersionOverride(t *testing.T) {

 	assert.Equal(t, client.ClientVersion(), expected)

 }

+// TestNegotiateAPVersionConnectionFailure asserts that we do not modify the

+// API version when failing to connect.

+func TestNegotiateAPVersionConnectionFailure(t *testing.T) {

+	const expected = "9.99"

+

+	client, err := NewClientWithOpts(WithHost("unix:///no-such-socket"))

+	assert.NilError(t, err)

+

+	client.version = expected

+	client.NegotiateAPIVersion(context.Background())

+	assert.Equal(t, client.ClientVersion(), expected)

+}

+

 func TestNegotiateAPIVersionAutomatic(t *testing.T) {

 	var pingVersion string

 	httpClient := newMockClient(func(req *http.Request) (*http.Response, error) {

@@ -14,7 +14,10 @@ import (

 // Ping pings the server and returns the value of the "Docker-Experimental",

 // "Builder-Version", "OS-Type" & "API-Version" headers. It attempts to use

 // a HEAD request on the endpoint, but falls back to GET if HEAD is not supported

-// by the daemon.

+// by the daemon. It ignores internal server errors returned by the API, which

+// may be returned if the daemon is in an unhealthy state, but returns errors

+// for other non-success status codes, failing to connect to the API, or failing

+// to parse the API response.

 func (cli *Client) Ping(ctx context.Context) (types.Ping, error) {

 	var ping types.Ping