protect highlight.js against unknown languages

falls back on autodetect if specified language fails (e.g. unrecognized language).

closes  #3268

IPython/frontend/html/notebook/static/js/notebookmain.js

@@ -1,115 +1,115
 //----------------------------------------------------------------------------
 //  Copyright (C) 2011  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // On document ready
 //============================================================================
 
 
 $(document).ready(function () {
 
     // monkey patch CM to be able to syntax highlight cell magics
     // bug reported upstream,
     // see https://github.com/marijnh/CodeMirror2/issues/670
     if(CodeMirror.getMode(1,'text/plain').indent == undefined ){
         console.log('patching CM for undefined indent');
         CodeMirror.modes.null = function() { return {token: function(stream) {stream.skipToEnd();},indent : function(){return 0}}}
         }
 
     CodeMirror.patchedGetMode = function(config, mode){
             var cmmode = CodeMirror.getMode(config, mode);
             if(cmmode.indent == null)
             {
                 console.log('patch mode "' , mode, '" on the fly');
                 cmmode.indent = function(){return 0};
             }
             return cmmode;
         }
     // end monkey patching CodeMirror
 
     IPython.mathjaxutils.init();
 
     IPython.read_only = $('body').data('readOnly') === 'True';
     $('#ipython-main-app').addClass('border-box-sizing');
     $('div#notebook_panel').addClass('border-box-sizing');
     // The header's bottom border is provided by the menu bar so we remove it.
     $('div#header').css('border-bottom-style','none');
 
     var baseProjectUrl = $('body').data('baseProjectUrl')
 
     IPython.page = new IPython.Page();
     IPython.layout_manager = new IPython.LayoutManager();
     IPython.pager = new IPython.Pager('div#pager', 'div#pager_splitter');
     IPython.quick_help = new IPython.QuickHelp('span#quick_help_area');
     IPython.login_widget = new IPython.LoginWidget('span#login_widget',{baseProjectUrl:baseProjectUrl});
     IPython.notebook = new IPython.Notebook('div#notebook',{baseProjectUrl:baseProjectUrl, read_only:IPython.read_only});
     IPython.save_widget = new IPython.SaveWidget('span#save_widget');
     IPython.menubar = new IPython.MenuBar('#menubar',{baseProjectUrl:baseProjectUrl})
     IPython.toolbar = new IPython.MainToolBar('#maintoolbar')
     IPython.tooltip = new IPython.Tooltip()
     IPython.notification_area = new IPython.NotificationArea('#notification_area')
     IPython.notification_area.init_notification_widgets();
 
     IPython.layout_manager.do_resize();
 
     $('body').append('<div id="fonttest"><pre><span id="test1">x</span>'+
                      '<span id="test2" style="font-weight: bold;">x</span>'+
                      '<span id="test3" style="font-style: italic;">x</span></pre></div>')
     var nh = $('#test1').innerHeight();
     var bh = $('#test2').innerHeight();
     var ih = $('#test3').innerHeight();
     if(nh != bh || nh != ih) {
         $('head').append('<style>.CodeMirror span { vertical-align: bottom; }</style>');
     }
     $('#fonttest').remove();
 
     if(IPython.read_only){
         // hide various elements from read-only view
         $('div#pager').remove();
         $('div#pager_splitter').remove();
 
         // set the notebook name field as not modifiable
         $('#notebook_name').attr('disabled','disabled')
     }
 
     IPython.page.show();
 
     IPython.layout_manager.do_resize();
     var first_load = function () {
         IPython.layout_manager.do_resize();
         var hash = document.location.hash;
         if (hash) {
             document.location.hash = '';
             document.location.hash = hash;
         }
         IPython.notebook.set_autosave_interval(IPython.notebook.minimum_autosave_interval);
         // only do this once
         $([IPython.events]).off('notebook_loaded.Notebook', first_load);
     };
     
     $([IPython.events]).on('notebook_loaded.Notebook', first_load);
     IPython.notebook.load_notebook($('body').data('notebookId'));
     
     if (marked) {
         marked.setOptions({
             gfm : true,
             tables: true,
             langPrefix: "language-",
             highlight: function(code, lang) {
                 var highlighted;
-                if (lang) {
+                try {
                     highlighted = hljs.highlight(lang, code, false);
-                } else {
+                } catch(err) {
                     highlighted = hljs.highlightAuto(code);
                 }
                 return highlighted.value;
             }
         })
     }
 
 });