Use contentMap, if available, when showing post diff

content.py

@@ -1463,7 +1463,8 @@ def content_diff(content: str, prev_content: str) -> str:
 
 
 def create_edits_html(edits_json: {}, post_json_object: {},
-                      translate: {}, timezone: str) -> str:
+                      translate: {}, timezone: str,
+                      system_language: str) -> str:
     """ Creates html showing historical edits made to a post
     """
     if not edits_json:
@@ -1471,20 +1472,42 @@ def create_edits_html(edits_json: {}, post_json_object: {},
     if not has_object_dict(post_json_object):
         return ''
     if not post_json_object['object'].get('content'):
+        if not post_json_object['object'].get('contentMap'):
             return ''
     edit_dates_list = []
     for modified, item in edits_json.items():
         edit_dates_list.append(modified)
     edit_dates_list.sort(reverse=True)
     edits_str = ''
-    content = remove_html(post_json_object['object']['content'])
+    content = None
+    if post_json_object['object'].get('contentMap'):
+        if post_json_object['object']['contentMap'].get(system_language):
+            content = \
+                post_json_object['object']['contentMap'][system_language]
+    if not content:
+        if post_json_object['object'].get('content'):
+            content = post_json_object['object']['content']
+    if not content:
+        return ''
+    content = remove_html(content)
     for modified in edit_dates_list:
         prev_json = edits_json[modified]
         if not has_object_dict(prev_json):
             continue
+        prev_content = None
         if not prev_json['object'].get('content'):
+            if not prev_json['object'].get('contentMap'):
                 continue
-        prev_content = remove_html(prev_json['object']['content'])
+        if prev_json['object'].get('contentMap'):
+            if prev_json['object']['contentMap'].get(system_language):
+                prev_content = \
+                    prev_json['object']['contentMap'][system_language]
+        if not prev_content:
+            if prev_json['object'].get('content'):
+                prev_content = prev_json['object']['content']
+        if not prev_content:
+            continue
+        prev_content = remove_html(prev_content)
         if content == prev_content:
             continue
         diff = content_diff(content, prev_content)

tests.py

@@ -6945,6 +6945,7 @@ def _test_diff_content() -> None:
         '<label class="diff_remove">- This is another line</label></p>'
     assert result == expected
 
+    system_language = "en"
     translate = {
         "SHOW EDITS": "SHOW EDITS"
     }
@@ -6973,13 +6974,16 @@ def _test_diff_content() -> None:
         },
         "2020-12-14T00:07:34Z": {
             "object": {
-                "content": content2,
+                "contentMap": {
+                    "en": content2
+                },
                 "published": "2020-12-14T00:07:34Z"
             }
         }
     }
     html_str = \
-        create_edits_html(edits_json, post_json_object, translate, timezone)
+        create_edits_html(edits_json, post_json_object, translate,
+                          timezone, system_language)
     assert html_str
     expected = \
         '<details><summary class="cw">SHOW EDITS</summary>' + \

webapp_post.py

@@ -1490,7 +1490,7 @@ def individual_post_as_html(signing_priv_key_pem: str,
         edits_json = load_json(edits_filename, 0, 1)
         if edits_json:
             edits_str = create_edits_html(edits_json, post_json_object,
-                                          translate, timezone)
+                                          translate, timezone, system_language)
 
     message_id_str = ''
     if message_id: