Fix version lock issue

Author: jesseduffield

pkg/commands/docker.go

@@ -70,6 +70,21 @@ func (c *DockerCommand) NewCommandObject(obj CommandObject) CommandObject {
 	return defaultObj
 }
 
+// newDockerClient creates a Docker client with the given host.
+// We avoid using client.FromEnv because it includes WithVersionFromEnv() which
+// sets manualOverride=true when DOCKER_API_VERSION is set, preventing API version
+// negotiation even when WithAPIVersionNegotiation() is specified.
+// Instead, we explicitly configure only what we need, and rely on proper
+// API version negotiation to support older Docker daemons.
+// See https://github.com/jesseduffield/lazydocker/issues/715
+func newDockerClient(dockerHost string) (*client.Client, error) {
+	return client.NewClientWithOpts(
+		client.WithTLSClientConfigFromEnv(),
+		client.WithAPIVersionNegotiation(),
+		client.WithHost(dockerHost),
+	)
+}
+
 // NewDockerCommand it runs docker commands
 func NewDockerCommand(log *logrus.Entry, osCommand *OSCommand, tr *i18n.TranslationSet, config *config.AppConfig, errorChan chan error) (*DockerCommand, error) {
 	dockerHost, err := determineDockerHost()
@@ -96,7 +111,7 @@ func NewDockerCommand(log *logrus.Entry, osCommand *OSCommand, tr *i18n.Translat
 		dockerHost = dockerHostFromEnv
 	}
 
-	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation(), client.WithHost(dockerHost))
+	cli, err := newDockerClient(dockerHost)
 	if err != nil {
 		ogLog.Fatal(err)
 	}

pkg/commands/docker_test.go

@@ -0,0 +1,63 @@
+package commands
+
+import (
+	"os"
+	"testing"
+
+	"github.com/docker/docker/client"
+	"github.com/stretchr/testify/assert"
+)
+
+// TestNewDockerClientVersionNegotiation verifies that newDockerClient allows
+// API version negotiation even when DOCKER_API_VERSION is set.
+//
+// This is a regression test for https://github.com/jesseduffield/lazydocker/issues/715
+// where users got "client version 1.25 is too old" errors because FromEnv()
+// includes WithVersionFromEnv() which sets manualOverride=true, preventing
+// API version negotiation.
+func TestNewDockerClientVersionNegotiation(t *testing.T) {
+	// Save original env var and restore after test
+	originalAPIVersion := os.Getenv("DOCKER_API_VERSION")
+	defer func() {
+		if originalAPIVersion == "" {
+			os.Unsetenv("DOCKER_API_VERSION")
+		} else {
+			os.Setenv("DOCKER_API_VERSION", originalAPIVersion)
+		}
+	}()
+
+	// Set DOCKER_API_VERSION to an old version that would cause
+	// "client version 1.25 is too old" errors if negotiation is disabled
+	os.Setenv("DOCKER_API_VERSION", "1.25")
+
+	t.Run("FromEnv locks version preventing negotiation", func(t *testing.T) {
+		// This demonstrates the problematic behavior we're avoiding.
+		// When using FromEnv with DOCKER_API_VERSION set, the client
+		// version gets locked to 1.25 and negotiation is disabled.
+		cli, err := client.NewClientWithOpts(
+			client.FromEnv,
+			client.WithAPIVersionNegotiation(),
+		)
+		assert.NoError(t, err)
+		defer cli.Close()
+
+		// Version is locked to the env var value
+		assert.Equal(t, "1.25", cli.ClientVersion())
+	})
+
+	t.Run("newDockerClient allows version negotiation", func(t *testing.T) {
+		// Test the actual production function.
+		// Use DefaultDockerHost for cross-platform compatibility
+		// (unix socket on Linux/macOS, named pipe on Windows).
+		cli, err := newDockerClient(client.DefaultDockerHost)
+		assert.NoError(t, err)
+		defer cli.Close()
+
+		// Version is NOT locked to the env var value (1.25).
+		// Instead, it uses the library's default version and will negotiate
+		// with the server on first request. This is the key difference that
+		// fixes the "version too old" error.
+		assert.NotEqual(t, "1.25", cli.ClientVersion(),
+			"client version should not be locked to DOCKER_API_VERSION env var")
+	})
+}