Merge pull request #2206 from getnikola/fix-2205

fix #2205

CHANGES.txt

@@ -14,6 +14,8 @@ Features
 Bugfixes
 --------
 
+* Decide is_mathjax based on current language tags (Issue #2205)
+
 New in v7.7.4
 =============
 

nikola/post.py

@@ -109,7 +109,6 @@ def __init__(
         self.base_url = self.config['BASE_URL']
         self.is_draft = False
         self.is_private = False
-        self.is_mathjax = False
         self.strip_indexes = self.config['STRIP_INDEXES']
         self.index_file = self.config['INDEX_FILE']
         self.pretty_urls = self.config['PRETTY_URLS']
@@ -223,9 +222,6 @@ def __init__(
         self.use_in_feeds = use_in_feeds and not is_draft and not is_private \
             and not self.publish_later
 
-        # If mathjax is a tag, or it's a ipynb post, then enable mathjax rendering support
-        self.is_mathjax = ('mathjax' in self.tags) or (self.compiler.name == 'ipynb')
-
         # Register potential extra dependencies
         self.compiler.register_extra_dependencies(self)
 
@@ -258,6 +254,17 @@ def _has_pretty_url(self, lang):
         else:
             return False
 
+    @property
+    def is_mathjax(self):
+        """True if this post has the mathjax tag in the current language or is a python notebook."""
+        if self.compiler.name == 'ipynb':
+            return True
+        lang = nikola.utils.LocaleBorg().current_lang
+        if self.is_translation_available(lang):
+            return 'mathjax' in self.tags_for_language(lang)
+        # If it has math in ANY other language, enable it. Better inefficient than broken.
+        return 'mathjax' in self.alltags
+
     @property
     def alltags(self):
         """Return ALL the tags for this post."""