update: always include name/summary/desc in index.xml if available

With the new localization support, the name/summary/description in the
metadata file becomes the global override.  So most apps are not going to
have those fields present in their metadata file.  This fixes the index.xml
generation to fall back to the localized versions of those fields when they
are not set in the metadata field.

https://forum.f-droid.org/t/what-has-happend-to-osmand

fdroidserver/index.py

@@ -258,6 +258,35 @@ def make_v0(apps, apks, repodir, repodict, requestsdict):
         el.appendChild(doc.createCDATASection(value))
         parent.appendChild(el)
 
+    def addElementCheckLocalized(name, app, key, doc, parent, default=''):
+        '''Fill in field from metadata or localized block
+
+        For name/summary/description, they can come only from the app source,
+        or from a dir in fdroiddata.  They can be entirely missing from the
+        metadata file if there is localized versions.  This will fetch those
+        from the localized version if its not available in the metadata file.
+        '''
+
+        el = doc.createElement(name)
+        value = app.get(key)
+        lkey = key[:1].lower() + key[1:]
+        localized = app.get('localized')
+        if not value and localized:
+            for lang in ['en-US'] + [x for x in localized.keys()]:
+                if not lang.startswith('en'):
+                    continue
+                if lang in localized:
+                    value = localized[lang].get(lkey)
+                    if value:
+                        break
+        if not value and localized and len(localized) > 1:
+            lang = list(localized.keys())[0]
+            value = localized[lang].get(lkey)
+        if not value:
+            value = default
+        el.appendChild(doc.createTextNode(value))
+        parent.appendChild(el)
+
     root = doc.createElement("fdroid")
     doc.appendChild(root)
 
@@ -312,16 +341,16 @@ def make_v0(apps, apks, repodir, repodict, requestsdict):
             addElement('added', app.added.strftime('%Y-%m-%d'), doc, apel)
         if app.lastUpdated:
             addElement('lastupdated', app.lastUpdated.strftime('%Y-%m-%d'), doc, apel)
-        addElement('name', app.Name, doc, apel)
-        addElement('summary', app.Summary, doc, apel)
+
+        addElementCheckLocalized('name', app, 'Name', doc, apel)
+        addElementCheckLocalized('summary', app, 'Summary', doc, apel)
+
         if app.icon:
             addElement('icon', app.icon, doc, apel)
 
-        if app.get('Description'):
-            description = app.Description
-        else:
-            description = '<p>No description available</p>'
-        addElement('desc', description, doc, apel)
+        addElementCheckLocalized('desc', app, 'Description', doc, apel,
+                                 '<p>No description available</p>')
+
         addElement('license', app.License, doc, apel)
         if app.Categories:
             addElement('categories', ','.join(app.Categories), doc, apel)