Import of Excel fails if the neutral resource file have been deleted

[Nisden]

Describe the bug
Resx Manager fails to import all translations when the neutral resource file have been deleted, but there still is a localized version.

• MyResource.resx
• MyResource.da.resx

To Reproduce

1. Create a resource file with a single row
2. Translate the row to another language
3. Export an Excel file of all rows
4. Delete the neutral resx file
5. Import the Excel file

Expected behavior
I would expect the ResxManager to skip importing the translation, similar to how it works if all the Resource files are deleted.

I tried debugging this a bit, but I was unable to detect where I would need to make my changes.
But I believe the primary culprit is here:

ResXResourceManager/src/ResXManager.Model/ResourceEntityExtensions.cs

Lines 204 to 218 in 647beb3

	var mappings = table.Skip(1)
	.Select(columns => new { Key = columns[0], TextColumns = columns.Skip(fixedColumnHeadersCount).Take(dataColumnCount).ToArray() })
	.Where(mapping => !string.IsNullOrEmpty(mapping.Key))
	.SelectMany(mapping => mapping.TextColumns.Select((column, index) =>
	new
	{
	mapping.Key,
	Entry = entity.Entries.SingleOrDefault(e => e.Key == mapping.Key) ?? entity.Add(mapping.Key),
	Text = column,
	Culture = dataColumnHeaders[index].ExtractCulture(),
	ColumnKind = dataColumnHeaders[index].GetColumnKind()
	}))
	.Where(mapping => mapping.Entry != null)
	.Select(mapping => new EntryChange(mapping.Entry!, mapping.Text, mapping.Culture, mapping.ColumnKind, mapping.Entry!.GetEntryData(mapping.Culture, mapping.ColumnKind)))
	.ToArray();

[tom-englert]

The neutral file is the key file, so removing it is nothing we need to support.
The project will be messed up any way, so what would be the use case?

[Nisden]

Hi Tom!

I agree its messed up, but it can happen when you have multiple developers and translators working in the same project on multiple branches. My real life case was that a developer deleted a section of the application (including translations), but our translator had already exported an excel file because they where adding a new language.

Honestly what was bugging me the most was the error message "Import failed partially. Some columns have been already imported, but not all." it provided no helpful hint on what was wrong.

Maybe listing what imports failed in the "output" tab would be helpful?