api/exec: fall back to system default DetachKeys when not provided

Author: DeveshB-1

pkg/api/handlers/compat/exec.go

@@ -82,6 +82,12 @@ func ExecCreateHandler(w http.ResponseWriter, r *http.Request) {
 	}
 	libpodConfig.ExitCommand = exitCommandArgs
 
+	// When DetachKeys was not provided, store the system default so that
+	// exec inspect returns a meaningful value rather than an empty string.
+	if libpodConfig.DetachKeys == nil {
+		libpodConfig.DetachKeys = &runtimeConfig.Engine.DetachKeys
+	}
+
 	// Run the exit command after 5 minutes, to mimic Docker's exec cleanup
 	// behavior.
 	libpodConfig.ExitCommandDelay = runtimeConfig.Engine.ExitCommandDelay