Turning on code generation for resource files with cultures in their names results in an error

[davkean]

1. File -> New -> Console Application (.NET Core)
2. Add New Resource called "Resource.en-US.resx

In the Error List:

Error		Custom tool PublicResXFileCodeGenerator failed to produce an output for input file 'Resource.en-US.resx' but did not log a specific error.	ConsoleApp181	c:\users\davkean\documents\visual studio 2017\Projects\ConsoleApp181\ConsoleApp181\Resource.en-US.resx	1	

Did some investigation - this appears to be (somewhat) by design by the code generator (seeResXFileCodeGenerator.GenerateCode) and has been it's behaviour since VS 2005 (yes 2005, not 2015). What is different in CPS though, is that it errors in this situation - whereas, the legacy project system outputs an empty source file.

Looking through the bug that caused them to implement this behavior was to avoid having both the neutral and the language-specific resource generate the same code and result in build errors. However, in some situations you don't have a neutral Resource file such as when your neutral resources end up in a satellite assembly. ie I don't think this behavior makes sense.

[davkean]

@nguerrera This was cause of your issue when you tried to do this.

[davkean]

Okay, thinking about this a little more I understand why they originally implemented this behavior - but I don't agree with the fix they made. Basically, they wanted to prevent the situation where you add multiple language-specific resources of the same resource file via Add Item, from getting code generated, as that will result in build errors.

Instead, I think we should fix this in a couple of ways:

1. If it is a language-specific resource and the language-neutral one already exists, we shouldn't turn on code generation for it.
2. We should let you specifically turn on code generation for it if you so want.

[niels-arch]

I also have this problem and unfortunately can not find a working solution for this! When I create a new project (.Net Core 2.0 Web application, Visual Studio 2017 Community, latest version) and follow the instructions of the site "https://docs.microsoft.com/en-us/aspnet/core/fundamentals/localization" (create resources directory and there for example a file "Resources / Models.ResTestModel.de.resx"), I always get the error message:
"Custom tool ResXFileCodeGenerator failed to make an output for input file ... but did not log a specific error". I have tested it on different systems. This is obviously the case when the language identifier (".de") appears in the file name of the resource file. Files without language recognition seem to work!
Can anyone offer a solution? I would be very grateful for this!

[bill-call]

For the sake of clarity, are we to understand that the work-around is to have a language-neutral .resx file in the same directory? If I understand @davkean correctly, this would cause the static class to be emitted, but would not prevent the error message for each .resx file that had a locale embedded in the file name, which is (sort of) okay, because the error itself is harmless, to the extent that it does not mean that your build is bad.

[bill-call]

Well, I tried the above. It does seem to stop the errors, and XXX.designer.cs does get generated for the neutral .resx file.

[bill-call]

Okay, for everybody playing along at home, let me see if I can summarize this:

If you do anything that causes ResXFileCodeGenerator to run (this happens if you create, modify or select for the first time a .resx file) when the target .resx file has a culture designator in the file name (it has a form like foo.en.resx or foo.en-US.resx), but you do not also have a culture-neutral .resx file of the same base name (foo.resx) in the same directory, then you will get this error. The error is correct, in that no class file was emitted, but it is wrong, in that it should not be an error. The fact that no class file was emitted is by design; the fact that this specific reason for not emitting it is now being flagged as an error is incorrect.

Absent a fix, we have two choices:

1. We can create a (otherwise unecessary) culture-neutral .resx file, which will cause the class to be emitted and thus prevent the error. If you choose this option, you don't have to put any strings in the culture-neutral file, so long as you specify a DefaultRequestCulture that points to one of your culture-specific .resx files. However; if you need to localize elements of your Model, you will need this class, and you will need it to add all the string IDs you need to use in your Model, but you can still leave the values blank.

2. We can just ignore the error, as it has no effect on the viability of the build.

In making the decision, it is important to understand that the "error" is merely flagging the fact that ResXFileCodeGenerator did not emit a class file. It is up to us to decide whether or not we care. Most of the time, particularly for a Asp.Net Core project, we don't care, but see the note above about localizing Model text.

If you are localizing Model values, do not put your resource files in a different directory. This is because the generated static class will be scoped (both class and properties) as internal, not public, and the localization logic in the model will not be able to see it.

You can still use a separate directory for your resource files, but you will either need to manually edit the resource class to give the IDs you care about public scope, or you will have to ensure that PublicResXFileCodeGenerator is used instead of ResXFileCodeGenerator. You can do that latter by opening the culture-neutral .resx file and setting the "Access Modifier" dropdown to "Public".

Update: the add-an-empty-culture-neutral-resx-file trick does not seem to work completely. If you modify a culture-specific .resx file, or if you manually run ResXFileCodeGenerator on it, you will still get the error.

[MohammedNoureldin]

Any news regarding this bug? Although it doesn't have an effect on building, it is still not ideal to always have 1..X errors in error list.

UPDATE: It is correct that this bug is just there until I restart Visual Studio? and then it disappears completely?

[Legends]

Ooooh my, even resources files are rendered useless, don't even want to think about digging deeper into ASP.NET Core 2.0.... Back to MVC 5... until ASP.NET Core v6 perhaps, see you then...

[davkean]

@mne91 Yes, closing the solution and reopen after removing the "Custom Tool" for the language-specific ResX (neutral can still have Custom Tool) in the properties windows. Basically, the legacy project system ignores and avoids showing this error, the new project system shows it. We'll fix it in a future update.

[RodrigoFCampos]

I am using windows 10 / iis / .net core 2.1 / latest vs 2017 and I must say that I have 2 resources files:

Resource.resx
Resource.en-US.resx

And sometimes (literally sometimes, because I can't reproduce this error when I want) I get the following error after a build:

Error Custom tool PublicResXFileCodeGenerator failed to produce an output for input file 'Resources\Resource.en-US.resx' but did not log a specific error.

I personally like the last part of the error "... but did not log a specific error." :)
I must say that this is a really strange error, because when I click on the error (in the "Error List" menu), the Resource file "Resource.en-US.resx" opens, then I close it, and I run another build and this time no errors appear.

To sum up, well I have no clue of what is happening :P
Am I missing something?