Fix thumbnail generation crash after resizing

misago/attachments/management/commands/processimageattachments.py

@@ -71,7 +71,7 @@ def process_attachment(self, settings: DynamicSettings, attachment: Attachment):
 
         if width > thumbnail_width or height > thumbnail_height:
             generate_attachment_thumbnail(
-                attachment, image, thumbnail_width, thumbnail_height
+                attachment, image, image.format, thumbnail_width, thumbnail_height
             )
 
         attachment.save(

misago/attachments/tests/test_generate_attachment_thumbnail.py

@@ -7,7 +7,7 @@ def test_generate_attachment_thumbnail_generates_thumbnail_image_and_updates_att
     image_attachment, image_large, teardown_attachments
 ):
     image = Image.open(image_large)
-    generate_attachment_thumbnail(image_attachment, image, 400, 300)
+    generate_attachment_thumbnail(image_attachment, image, image.format, 400, 300)
 
     assert image_attachment.thumbnail
     assert image_attachment.thumbnail.url

misago/attachments/tests/test_store_uploaded_file.py

@@ -135,6 +135,40 @@ def test_store_uploaded_file_stores_image_file_scaled_down(
     assert not attachment.thumbnail_size
 
 
+@override_dynamic_settings(
+    attachment_image_max_width=400,
+    attachment_image_max_height=300,
+    attachment_thumbnail_width=150,
+    attachment_thumbnail_height=100,
+)
+def test_store_uploaded_file_stores_image_file_scaled_down_with_thumbnail(
+    user, dynamic_settings, image_large, teardown_attachments
+):
+    with open(image_large, "rb") as fp:
+        upload = SimpleUploadedFile("image.png", fp.read(), "image/png")
+
+    request = Mock(user=user, settings=dynamic_settings)
+    filetype = filetypes.match_filetype(upload.name)
+
+    attachment = store_uploaded_file(request, upload, filetype)
+
+    assert attachment.id
+    assert attachment.uploader == user
+    assert attachment.uploader_name == user.username
+    assert attachment.uploader_slug == user.slug
+    assert attachment.uploaded_at
+    assert attachment.name == upload.name
+    assert attachment.slug == "image-png"
+    assert attachment.filetype_id == filetype.id
+    assert attachment.dimensions == "300x300"
+    assert attachment.upload
+    assert attachment.upload.url
+    assert attachment.size == upload.size
+
+    assert attachment.thumbnail
+    assert attachment.thumbnail_dimensions == "100x100"
+
+
 def test_store_uploaded_file_cleans_filename(
     user, dynamic_settings, text_file, teardown_attachments
 ):

misago/attachments/thumbnails.py

@@ -7,13 +7,12 @@
 
 
 def generate_attachment_thumbnail(
-    attachment: Attachment, image, width: int, height: int
+    attachment: Attachment, image, image_format: str, width: int, height: int
 ):
     thumbnail_stream = BytesIO()
-    format = image.format
 
     image.thumbnail((width, height))
-    image.save(thumbnail_stream, format)
+    image.save(thumbnail_stream, image_format)
 
     attachment.thumbnail = SimpleUploadedFile(
         attachment.name,

misago/attachments/upload.py

@@ -163,7 +163,7 @@ def _store_attachment_image(
 
     if image.width > thumbnail_width or image.height > thumbnail_height:
         generate_attachment_thumbnail(
-            attachment, image, thumbnail_width, thumbnail_height
+            attachment, image, image_format, thumbnail_width, thumbnail_height
         )