From 984ef9072c95daa41f9fc6c4d2e424c51a6ed6be Mon Sep 17 00:00:00 2001
From: Laura Brehm <laurabrehm@hey.com>
Date: Wed, 7 Aug 2024 14:04:31 +0100
Subject: [PATCH] plugins: don't panic on Close if PluginServer nil
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Signed-off-by: Laura Brehm <laurabrehm@hey.com>
(cherry picked from commit 9c4480604e0dd00b8256e23c31a5bc2af4e06eac)
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
---
 cli-plugins/socket/socket.go      |  3 +++
 cli-plugins/socket/socket_test.go | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/cli-plugins/socket/socket.go b/cli-plugins/socket/socket.go
index 7096b42b2e..9a76f7a780 100644
--- a/cli-plugins/socket/socket.go
+++ b/cli-plugins/socket/socket.go
@@ -95,6 +95,9 @@ func (pl *PluginServer) Addr() net.Addr {
 //
 // The error value is that of the underlying [net.Listner.Close] call.
 func (pl *PluginServer) Close() error {
+	if pl == nil {
+		return nil
+	}
 	logrus.Trace("Closing plugin server")
 	// Close connections first to ensure the connections get io.EOF instead
 	// of a connection reset.
diff --git a/cli-plugins/socket/socket_test.go b/cli-plugins/socket/socket_test.go
index df7b351181..7d786abfc6 100644
--- a/cli-plugins/socket/socket_test.go
+++ b/cli-plugins/socket/socket_test.go
@@ -117,6 +117,18 @@ func TestPluginServer(t *testing.T) {
 		assert.NilError(t, err, "failed to dial returned server")
 		checkDirNoNewPluginServer(t)
 	})
+
+	t.Run("does not panic on Close if server is nil", func(t *testing.T) {
+		var srv *PluginServer
+		defer func() {
+			if r := recover(); r != nil {
+				t.Errorf("panicked on Close")
+			}
+		}()
+
+		err := srv.Close()
+		assert.NilError(t, err)
+	})
 }
 
 func checkDirNoNewPluginServer(t *testing.T) {