[vcpkg-tool] Add an option to build a minimal feature set based on `"default-features": false`

[Thomas1664]

Over the years, there was a lot of confusion because "default-features": false is ignored in transitive dependencies: #26664 (comment) . Many users expect vcpkg to build a minimal set of features instead which does not include default features that were disabled by a port between the manifest of a user and the port declaring the default feature.

In summary, we don't need to pull in disabled features if they aren't enabled by something else that didn't specify "default-features": false.

@BillyONeal suggested to add an option to avoid unwanted features and to enable this behaviour by default in manifest mode: #11602 (comment)

Many people have fallen into this trap and the current behaviour might actually lead to longer builds rather than avoiding rebuilds.

All related issues: #31290, #31230, #30695, #26664, #24548, #17033, #11602

[autoantwort]

Would be solved by microsoft/vcpkg-tool#538

[dg0yt]

Can you change the issue title to not say "ignore"? It is not ignored (as you have been told). It just means three different things.

[Thomas1664]

Can you change the issue title to not say "ignore"? It is not ignored (as you have been told). It just means three different things.

I think "ignore" sufficient because it describes the observed effect. Do you have a better word in mind?

[dg0yt]

It has the effect it is designed to have. So I observe that it is not ignored

As I said, IMO the problem is that default-features has three different "overloads", two of them having even the same "signature":

• as a feature list in port manifest. (A)
• true/false in dependencies in a port manifest. (B)
• true/false in dependencies in a user manifest. (C)

You expect the C behavior for B.

Apart from this it is a clear situation:

• Only the author of an independent port decides about the default set of features to install if no more precise spec is given. (A)
• Only the user (manifest) decides whether to not use the default set of features. (C)
• For any port in the middle, authors must decide if they conveniently rely on default features (and reduce user choice) or if they fully specify the set of feature dependencies. (B)

[Thomas1664]

@dg0yt Can you suggest a better title?

@FrankXie05 This is not a question. My request is to implement the PR tagged by @autoantwort: microsoft/vcpkg-tool#538

[dg0yt]

I guess the best fit is:
"Add an option to install with minimum dependencies"

(I wouldn't use "minimum features" because vcpkg install gdal continues to mean installation of the default features of port gdal. You only want to trim the tree of dependencies.)

[JackBoosY]

Should be vcpkg feature.