Change avatar error message to include allowed file formats

app/models/concerns/avatarable.rb

@@ -22,7 +22,7 @@ module Avatarable
 
   def avatar_type
     unless self.avatar.image?
-      self.errors.add :avatar, "only images allowed"
+      errors.add :avatar, "file format is not supported. Please try one of the following supported formats: #{AvatarUploader::IMAGE_EXT.join(', ')}"
     end
   end
 

changelogs/unreleased/43771-improve-avatar-error-message.yml

+---
+title: Change avatar error message to include allowed file formats
+merge_request: 17747
+author: Fabian Schneider
+type: changed

spec/models/group_spec.rb

@@ -241,7 +241,7 @@ describe Group do
 
     it "is false if avatar is html page" do
       group.update_attribute(:avatar, 'uploads/avatar.html')
-      expect(group.avatar_type).to eq(["only images allowed"])
+      expect(group.avatar_type).to eq(["file format is not supported. Please try one of the following supported formats: png, jpg, jpeg, gif, bmp, tiff"])
     end
   end
 

spec/models/project_spec.rb

@@ -1055,7 +1055,7 @@ describe Project do
 
     it 'is false if avatar is html page' do
       project.update_attribute(:avatar, 'uploads/avatar.html')
-      expect(project.avatar_type).to eq(['only images allowed'])
+      expect(project.avatar_type).to eq(['file format is not supported. Please try one of the following supported formats: png, jpg, jpeg, gif, bmp, tiff'])
     end
   end
 

spec/models/user_spec.rb

@@ -1250,7 +1250,7 @@ describe User do
     it 'is false if avatar is html page' do
       user.update_attribute(:avatar, 'uploads/avatar.html')
 
-      expect(user.avatar_type).to eq(['only images allowed'])
+      expect(user.avatar_type).to eq(['file format is not supported. Please try one of the following supported formats: png, jpg, jpeg, gif, bmp, tiff'])
     end
   end