MDL-31832 CLI upgrade checks if the upgrade is actually needed

admin/cli/upgrade.php

@@ -92,6 +92,10 @@ if ($version < $CFG->version) {
 $oldversion = "$CFG->release ($CFG->version)";
 $newversion = "$release ($version)";
 
+if (!moodle_needs_upgrading()) {
+    cli_error(get_string('cliupgradenoneed', 'core_admin', $newversion), 63);
+}
+
 // Test environment first.
 list($envstatus, $environment_results) = check_moodle_environment(normalize_version($release), ENV_SELECT_RELEASE);
 if (!$envstatus) {

lang/en/admin.php

@@ -105,6 +105,7 @@ $string['cliunknowoption'] = 'Unrecognised options:
   {$a}
 Please use --help option.';
 $string['cliupgradefinished'] = 'Command line upgrade completed successfully.';
+$string['cliupgradenoneed'] = 'No upgrade needed for the installed version {$a}. Thanks for coming anyway!';
 $string['cliyesnoprompt'] = 'type y (means yes) or n (means no)';
 $string['commentsperpage'] = 'Comments displayed per page';
 $string['commonfiltersettings'] = 'Common filter settings';