Force UTF-8 encoding for Exchange folders (fixes #2152)

lib/import/exchange/folder.rb

@@ -25,7 +25,8 @@ module Import
       end
 
       def find(id)
-        @lookup_map[id] ||= @connection.get_folder(id)
+        (@lookup_map[id] ||= @connection.get_folder(id)) ||
+          id_folder_map[id]
       end
 
       def all
@@ -42,21 +43,14 @@ module Import
       end
 
       def display_path(folder)
-        display_name = folder.display_name
-        return display_name if !folder.parent_folder_id
-
+        display_name  = folder.display_name.utf8_encode(fallback: :read_as_sanitized_binary)
         parent_folder = find(folder.parent_folder_id)
-        return display_name if !parent_folder
 
-        parent_folder = id_folder_map[folder.parent_folder_id]
-        return display_name if !parent_folder
+        return display_name if parent_folder.blank?
 
-        # recursive
-        parent_folder_path = display_path(parent_folder)
-
-        "#{parent_folder_path} -> #{display_name}"
+        "#{display_path(parent_folder)} -> #{display_name}"
       rescue Viewpoint::EWS::EwsError
-        folder.display_name
+        display_name
       end
 
       private

spec/lib/import/exchange/folder_spec.rb

@@ -0,0 +1,33 @@
+require 'rails_helper'
+
+RSpec.describe Import::Exchange::Folder do
+  # see https://github.com/zammad/zammad/issues/2152
+  # WARNING! This test is closely tied to the implementation. :(
+  describe '#display_path (#2152)' do
+    let(:subject)        { described_class.new(connection) }
+    let(:connection)     { instance_double('Viewpoint::EWSClient') }
+    let(:root_folder)    { double('EWS Folder') }
+    let(:child_folder)   { double('EWS Folder') }
+    let(:exception_case) { double('EWS Folder') }
+
+    before do
+      allow(root_folder).to receive(:display_name).and_return('你好'.b)
+      allow(root_folder).to receive(:parent_folder_id).and_return(nil)
+
+      allow(child_folder).to receive(:display_name).and_return('你好'.b)
+      allow(child_folder).to receive(:parent_folder_id).and_return(1)
+
+      allow(exception_case).to receive(:display_name).and_return('你好'.b)
+      allow(exception_case).to receive(:parent_folder_id).and_raise(Viewpoint::EWS::EwsError)
+
+      allow(subject).to receive(:find).with(any_args).and_return(root_folder)
+      allow(subject).to receive(:find).with(nil).and_return(nil)
+    end
+
+    it 'returns a valid UTF-8 string' do
+      expect { subject.display_path(root_folder).to_json }.not_to raise_error
+      expect { subject.display_path(child_folder).to_json }.not_to raise_error
+      expect { subject.display_path(exception_case).to_json }.not_to raise_error
+    end
+  end
+end