[scrolller] fix exception for albums with missing media (#7428)

fixes regression introduced in a44ea6b3d9

gallery_dl/extractor/scrolller.py

@@ -56,7 +56,12 @@ class ScrolllerExtractor(Extractor):
 
         files = []
         for num, media in enumerate(album, 1):
-            src = max(media["mediaSources"], key=self._sort_key)
+            sources = media.get("mediaSources")
+            if not sources:
+                self.log.warning("%s/%s: Missing media file",
+                                 post.get("id"), num)
+                continue
+            src = max(sources, key=self._sort_key)
             src["num"] = num
             files.append(src)
         return files

gallery_dl/version.py

@@ -6,5 +6,5 @@
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
 
-__version__ = "1.29.5"
+__version__ = "1.29.6-dev"
 __variant__ = None

test/results/scrolller.py

@@ -73,6 +73,7 @@ __tests__ = (
 
 {
     "#url"    : "https://scrolller.com/long-comic-the-twelve-tasks-of-eve-12ch1ve8ko",
+    "#comment": "album post (#7339)",
     "#class"  : scrolller.ScrolllerPostExtractor,
     "#pattern": r"https://static\.scrolller\.com/\w+/long-comic-the-twelve-tasks-of-eve-\d+-\w+\.png",
     "#count"  : 177,
@@ -81,6 +82,17 @@ __tests__ = (
     "num"  : range(1, 177),
 },
 
+{
+    "#url"    : "https://scrolller.com/some-quick-news-tboi-rule-34-mod-czedll1bum",
+    "#comment": "album post with empty 'mediaSources' (#7428)",
+    "#class"  : scrolller.ScrolllerPostExtractor,
+    "#urls"   : "https://static.scrolller.com/gamma/some-quick-news-tboi-rule-34-mod-1-50uolks94u.png",
+    "#count"  : 1,
+
+    "count": 1,
+    "num"  : 1,
+},
+
 {
     "#url"    : "https://scrolller.com/following",
     "#class"  : scrolller.ScrolllerFollowingExtractor,