vcpkg export with feature does not work anymore

[gix]

Describe the bug

vcpkg export fails when using features. This recently broke (probably microsoft/vcpkg-tool#298?).

Environment

• OS: Windows
• Compiler: N/A

To Reproduce
Steps to reproduce the behavior:

1. .\vcpkg.exe install 'abseil[cxx17]'

2. .\vcpkg export abseil[cxx17] --nuget

   Error: List of features is not allowed in this contectExample:
     vcpkg export zlib zlib:x64-windows boost --nuget
   

3. .\vcpkg export abseil --nuget

   The following packages need to be built:
       abseil:x86-windows
   There are packages that have not been built.
   To build them, run:
       vcpkg install abseil:x86-windows
   

Expected behavior
Exporting a port with feature works as before.

[JackBoosY]

Yeah, but we may end up deprecating including features because the body of the export is a port instead of a feature.

[JackBoosY]

@ras0219-msft Is this changes by design?

[ras0219-msft]

Because export does not install or remove packages, the set of features has always had no substantial effect except perhaps failing if the features were not currently installed. Therefore, if you had a configuration before that worked, the workaround is simply to remove the feature list from the packages list. All currently installed features of the selected packages will be exported.

However, we'll still need to look into this as a scripting regression and perhaps issue a warning instead that features on the cli have no effect for the export command.

Thanks for posting this issue!

[daschuer]

If you consider a scripting environment where the same string is used to install and export the ports, it makes perfectly sens to have the list of features also during export. The alternative would be some magic string handling to remove the features, or using --x-all-installed. The later might be export deprecated packages that have been installed earlier.

[FrankHeimes]

This situation is unsatisfying. The latest version of vcpkg can not do what previous calls .\vcpkg.exe install 'opencv4[contrib]' did for me, i. e. downloading and installing a few header files for the Aruco extension of OpenCV

For OpenCV, a workaround is to patch vcproj.json to include "contrib" into the list of "default-features".

But that defies the whole point of vcpkg to automagically install all required packages.

[invy]

Therefore, if you had a configuration before that worked, the workaround is simply to remove the feature list from the packages list. All currently installed features of the selected packages will be exported.

Not very nice workaround, it either requires editing a bunch of build configuration, or doing some not really needed scripting.

However, we'll still need to look into this as a scripting regression and perhaps issue a warning instead that features on the cli have no effect for the export command.

The problem appears in scripting environment. It is also related to the package dependencies. So I think the logic here could look like:

1. Export accepts packages with features.
2. Export verifies whether packages with corresponding features are installed, if no, there should be either warning or error. I.e. User has installed curl, but wants to export curl[ssh] which requires also libssh to be present, so it's a nice check.
3. Existing scripting environments should not break.

[pkeir]

Any update on this? I rely on vcpkg export opencv[contrib], but now I get the message "error: list of features is not allowed in this context". Is there a workaround?

[dg0yt]

AFAIU the answer was that features don't make sense for the export command: #22913 (comment)

There was the idea of adding a more tolerant behaviour, but maybe this tolerance is no longer relevant after almost two years.

[pkeir]

Thanks. I had misread that comment. The advice in my case would be to use vcpkg export opencv. I'll give that a try.

(I had been thinking of opencv[contrib] as adding a component (contrib) rather than specifying a feature.)