nmcli: warn if daemon version mismatch

When updating NetworkManager to a new version, normally the service is
not restarted by the installer to avoid interrupting networking.
However, next nmcli invocation will use the updated version, but against
the older version of the daemon that is still running. Although this is
suposed to work, it is advisable that nmcli and daemon's versions are
the same. Emit a warning recommending restarting the daemon.

Add nmcli test to check the new feature. To avoid breaking the existing
tests, test-networkmanager-service now reports the same version than the
running nmcli except if it's instructed to report a different one.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1703
(cherry picked from commit fb851f3294fbf8ab1243dc6fcceef5adf0a403bd)

7 files changed, 81 insertions, 5 deletions

diff --git a/Makefile.am b/Makefile.am
index d49b92c719..1e09199612 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5522,6 +5522,7 @@ EXTRA_DIST += \
 	src/tests/client/test-client.check-on-disk/test_003.expected \
 	src/tests/client/test-client.check-on-disk/test_004.expected \
 	src/tests/client/test-client.check-on-disk/test_offline.expected \
+	src/tests/client/test-client.check-on-disk/test_version_warn.expected \
 	\
 	src/tests/client/meson.build \
 	$(NULL)
diff --git a/src/nmcli/common.c b/src/nmcli/common.c
index 2e8ded7e44..518faa2f73 100644
--- a/src/nmcli/common.c
+++ b/src/nmcli/common.c
@@ -1250,6 +1250,7 @@ got_client(GObject *source_object, GAsyncResult *res, gpointer user_data)
                                 error->message);
     } else {
         nmc->client = NM_CLIENT(source_object);
+        nmc_warn_if_version_mismatch(nmc->client);
         call_cmd(nmc,
                  g_steal_pointer(&task),
                  call->cmd,
diff --git a/src/nmcli/utils.c b/src/nmcli/utils.c
index 5fb1ba794f..29e84cc25c 100644
--- a/src/nmcli/utils.c
+++ b/src/nmcli/utils.c
@@ -1822,3 +1822,19 @@ print_data(const NmcConfig     *nmc_config,
                               field_values);
     }
 }
+
+void
+nmc_warn_if_version_mismatch(NMClient *client)
+{
+    const char *nm_ver;
+
+    g_return_if_fail(client != NULL);
+
+    nm_ver = nm_client_get_version(client);
+    if (!nm_streq0(nm_ver, VERSION)) {
+        g_printerr(_("Warning: nmcli (%s) and NetworkManager (%s) versions don't match. "
+                     "Restarting NetworkManager is advised.\n"),
+                   VERSION,
+                   nm_ver ? nm_ver : _("Unknown"));
+    }
+}
diff --git a/src/nmcli/utils.h b/src/nmcli/utils.h
index 6c1fb1db1a..0960c45c6f 100644
--- a/src/nmcli/utils.h
+++ b/src/nmcli/utils.h
@@ -72,6 +72,8 @@ void            print_data(const NmcConfig     *nmc_config,
                            int                  indent,
                            const NmcOutputData *out);
 
+void nmc_warn_if_version_mismatch(NMClient *client);
+
 /*****************************************************************************/
 
 extern const NMMetaEnvironment *const nmc_meta_environment;
diff --git a/src/tests/client/test-client.check-on-disk/test_version_warn.expected b/src/tests/client/test-client.check-on-disk/test_version_warn.expected
new file mode 100644
index 0000000000..3a22d726d2
--- /dev/null
+++ b/src/tests/client/test-client.check-on-disk/test_version_warn.expected
@@ -0,0 +1,30 @@
+size: 263
+location: src/tests/client/test-client.py:test_version_warn()/1
+cmd: $NMCLI c
+lang: C
+returncode: 0
+stdout: 1 bytes
+>>>
+
+
+<<<
+stderr: 110 bytes
+>>>
+Warning: nmcli (X.Y.Z) and NetworkManager (A.B.C) versions don't match. Restarting NetworkManager is advised.
+
+<<<
+size: 273
+location: src/tests/client/test-client.py:test_version_warn()/2
+cmd: $NMCLI c
+lang: pl_PL.UTF-8
+returncode: 0
+stdout: 1 bytes
+>>>
+
+
+<<<
+stderr: 110 bytes
+>>>
+Warning: nmcli (X.Y.Z) and NetworkManager (A.B.C) versions don't match. Restarting NetworkManager is advised.
+
+<<<
diff --git a/src/tests/client/test-client.py b/src/tests/client/test-client.py
index b618fb9703..baa229cfc5 100755
--- a/src/tests/client/test-client.py
+++ b/src/tests/client/test-client.py
@@ -713,6 +713,14 @@ class Util:
             extra_env,
         )
 
+    @staticmethod
+    def get_nmcli_version():
+        ver = NM.utils_version()
+        micro = ver & 0xFF
+        minor = (ver >> 8) & 0xFF
+        major = ver >> 16
+        return f"{major}.{minor}.{micro}"
+
 
 ###############################################################################
 
@@ -834,11 +842,15 @@ class NMStubServer:
         except:
             return None
 
-    def __init__(self, seed):
+    def __init__(self, seed, version=None):
         service_path = PathConfiguration.test_networkmanager_service_path()
         self._conn = dbus.SessionBus()
         env = os.environ.copy()
         env["NM_TEST_NETWORKMANAGER_SERVICE_SEED"] = seed
+        if version is not None:
+            env["NM_TEST_NETWORKMANAGER_SERVICE_VERSION"] = version
+        else:
+            env["NM_TEST_NETWORKMANAGER_SERVICE_VERSION"] = Util.get_nmcli_version()
         p = subprocess.Popen(
             [sys.executable, service_path], stdin=subprocess.PIPE, env=env
         )
@@ -1069,9 +1081,9 @@ class NMTestContext:
         self._calling_num[calling_fcn] = calling_num
         return calling_num
 
-    def srv_start(self):
+    def srv_start(self, srv_version=None):
         self.srv_shutdown()
-        self.srv = NMStubServer(self.testMethodName)
+        self.srv = NMStubServer(self.testMethodName, srv_version)
 
     def srv_shutdown(self):
         if self.srv is not None:
@@ -2245,6 +2257,18 @@ class TestNmcli(unittest.TestCase):
         nmc.pexp.expect("NetworkManager is stopped")
         end_mon(self, nmc)
 
+    @nm_test_no_dbus  # we need dbus, but we need to pass arguments to srv_start
+    def test_version_warn(self):
+        self.ctx.srv_start(srv_version="A.B.C")
+        self.call_nmcli_l(
+            ["c"],
+            replace_stderr=[
+                Util.ReplaceTextRegex(
+                    r"\(" + Util.get_nmcli_version() + r"\)", "(X.Y.Z)"
+                )
+            ],
+        )
+
 
 ###############################################################################
 
@@ -2675,7 +2699,7 @@ def main():
                     sys.executable,
                     __file__,
                     "--started-with-dbus-session",
-                    *sys.argv[1:]
+                    *sys.argv[1:],
                 )
             except OSError as e:
                 if e.errno != errno.ENOENT:
diff --git a/tools/test-networkmanager-service.py b/tools/test-networkmanager-service.py
index 8221804143..9a42312324 100755
--- a/tools/test-networkmanager-service.py
+++ b/tools/test-networkmanager-service.py
@@ -1587,7 +1587,9 @@ class NetworkManager(ExportedObj):
             PRP_NM_ACTIVATING_CONNECTION: ExportedObj.to_path(None),
             PRP_NM_STARTUP: False,
             PRP_NM_STATE: dbus.UInt32(NM.State.DISCONNECTED),
-            PRP_NM_VERSION: "0.9.9.0",
+            PRP_NM_VERSION: os.environ.get(
+                "NM_TEST_NETWORKMANAGER_SERVICE_VERSION", "0.9.9.0"
+            ),
             PRP_NM_CONNECTIVITY: dbus.UInt32(NM.ConnectivityState.NONE),
         }