Ensure loading of MathJax bundle is optional (#2919)

* Ensure loading of MathJax bundle is optional

* Fix flake

* Fix autoload_js

panel/io/notebook.py

@@ -241,7 +241,7 @@ def load_notebook(inline=True, load_timeout=5000):
     user_resources = settings.resources._user_value is not _Unset
     resources = Resources.from_bokeh(resources)
     try:
-        bundle = bundle_resources(resources)
+        bundle = bundle_resources(None, resources)
         bundle = Bundle.from_bokeh(bundle)
         configs, requirements, exports, skip_imports = require_components()
         ipywidget = 'ipywidgets_bokeh' in sys.modules

panel/io/resources.py

@@ -2,6 +2,7 @@
 Patches bokeh resources to make it easy to add external JS and CSS
 resources via the panel.config object.
 """
+import copy
 import glob
 import json
 import os
@@ -15,7 +16,7 @@
 
 from bokeh.embed.bundle import (
     Bundle as BkBundle, _bundle_extensions, extension_dirs,
-    bundle_models
+    bundle_models, _use_mathjax
 )
 
 from bokeh.resources import Resources as BkResources
@@ -98,7 +99,8 @@ def bundled_files(model, file_type='javascript'):
     return files
 
 
-def bundle_resources(resources):
+def bundle_resources(roots, resources):
+    from ..config import panel_extension as ext
     global RESOURCE_MODE
     js_resources = css_resources = resources
     RESOURCE_MODE = mode = js_resources.mode if resources is not None else "inline"
@@ -108,13 +110,20 @@ def bundle_resources(resources):
     css_files = []
     css_raw = []
 
-    js_files.extend(js_resources.js_files)
-    js_raw.extend(js_resources.js_raw)
+    use_mathjax = (_use_mathjax(roots) or 'mathjax' in ext._loaded_extensions) if roots else True
+
+    if js_resources:
+        js_resources = copy.deepcopy(js_resources)
+        if not use_mathjax and "bokeh-mathjax" in js_resources.js_components:
+            js_resources.js_components.remove("bokeh-mathjax")
+
+        js_files.extend(js_resources.js_files)
+        js_raw.extend(js_resources.js_raw)
 
     css_files.extend(css_resources.css_files)
     css_raw.extend(css_resources.css_raw)
 
-    extensions = _bundle_extensions(None, js_resources)
+    extensions = _bundle_extensions(roots, js_resources)
     if mode == "inline":
         js_raw.extend([ Resources._inline(bundle.artifact_path) for bundle in extensions ])
     elif mode == "server":

panel/io/save.py

@@ -8,7 +8,6 @@
 import bokeh
 
 from bokeh.document.document import Document
-from bokeh.embed.bundle import bundle_for_objs_and_resources
 from bokeh.embed.elements import html_page_for_render_items
 from bokeh.embed.util import OutputDocumentFor, standalone_docs_json_and_render_items
 from bokeh.io.export import get_screenshot_as_png
@@ -19,7 +18,10 @@
 from ..config import config
 from .embed import embed_state
 from .model import add_to_doc
-from .resources import BASE_TEMPLATE, DEFAULT_TITLE, Bundle, Resources, set_resource_mode
+from .resources import (
+    BASE_TEMPLATE, DEFAULT_TITLE, Bundle, Resources, bundle_resources,
+    set_resource_mode
+)
 from .state import state
 
 #---------------------------------------------------------------------
@@ -134,7 +136,7 @@ def file_html(models, resources, title=None, template=BASE_TEMPLATE,
             models_seq, suppress_callback_warning=True
         )
         title = _title_from_models(models_seq, title)
-        bundle = bundle_for_objs_and_resources(None, resources)
+        bundle = bundle_resources(models_seq, resources)
         bundle = Bundle.from_bokeh(bundle)
         return html_page_for_render_items(
             bundle, docs_json, render_items, title=title, template=template,

panel/io/server.py

@@ -155,13 +155,13 @@ def server_html_page_for_session(session, resources, title, template=BASE_TEMPLA
     if template_variables is None:
         template_variables = {}
 
-    bundle = bundle_resources(resources)
+    bundle = bundle_resources(session.document.roots, resources)
     return html_page_for_render_items(bundle, {}, [render_item], title,
         template=template, template_variables=template_variables)
 
-def autoload_js_script(resources, token, element_id, app_path, absolute_url):
+def autoload_js_script(doc, resources, token, element_id, app_path, absolute_url):
     resources = Resources.from_bokeh(resources)
-    bundle = bundle_resources(resources)
+    bundle = bundle_resources(doc.roots, resources)
 
     render_items = [RenderItem(token=token, elementid=element_id, use_for_title=False)]
     bundle.add(Script(script_for_render_items({}, render_items, app_path=app_path, absolute_url=absolute_url)))
@@ -260,7 +260,10 @@ async def get(self, *args, **kwargs):
             state.curdoc = session.document
             try:
                 resources = Resources.from_bokeh(self.application.resources(server_url))
-                js = autoload_js_script(resources, session.token, element_id, app_path, absolute_url)
+                js = autoload_js_script(
+                    session.document, resources, session.token, element_id,
+                    app_path, absolute_url
+                )
             finally:
                 state.curdoc = None