Fix a bunch of cases where default features were incorrectly included

[cqundefine]

In some cases related to host dependencies, default features were being included even those they were disabled, found this when cross compiling qtbase with default features disabled.

[Copilot]

Pull request overview

This PR fixes cases where default features were being incorrectly included, particularly around host dependencies (notably when cross-compiling with default features disabled). It updates dependency planning behavior and adds regression tests to ensure host/target default-feature metadata is handled as intended.

Changes:

• Prevents adding a default-feature reinstall requirement for non-user-requested clusters when the package isn’t installed.
• Adjusts versioned dependency graph handling so host dependencies don’t get implicit default features; default features for versioned plans are only emitted when enabled for the node.
• Adds new unit tests covering host dependency default-feature suppression in both classic and versioned planning.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/vcpkg/dependencies.cpp	Fixes default-feature inclusion logic in both classic cluster reinstall handling and versioned dependency planning (esp. host deps).
src/vcpkg-test/plan.cpp	Adds tests asserting host-dependency default-feature metadata is suppressed appropriately in classic plans.
src/vcpkg-test/dependencies.cpp	Adds a versioned-plan test ensuring host dependencies respect explicit no-defaults.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

[dg0yt]

I would like to see the exact install command and problem before the change.

[dg0yt]

(For such cases, I prefer to push tests first, to demonstrate the error in CI.)

[cqundefine]

I would like to see the exact install command and problem before the change.

Right, so with this simple test package (just added it to the vcpkg repository for testing):

{
  "name": "testport",
  "version": "0.0.0",
  "description": "test",
  "dependencies": [
    {
      "name": "testport",
      "host": true,
      "default-features": false
    }
  ],
  "default-features": [
    "a"
  ],
  "features": {
    "a": {
      "description": "a"
    }
  }
}

Calling ./vcpkg install testport[core] --triplet=arm64-linux it incorrectly included the a feature for the host build (in my case x64-linux:

Computing installation plan...
The following packages will be built and installed:
  * testport[a,core]:[email protected]
    testport:[email protected]

Running the same command with a binary built with those fixes it correctly skips adding the a feature:

Computing installation plan...
The following packages will be built and installed:
  * testport:[email protected]
    testport:[email protected]

(For such cases, I prefer to push tests first, to demonstrate the error in CI.)

Do you think that is something I should do now, like revert the fix, let the CI run and then readd the fix?

[Osyotr]

Calling ./vcpkg install testport[core] --triplet=arm64-linux it incorrectly included the a feature for the host build (in my case x64-linux

This is not nice but expected, should've been ./vcpkg install testport[core] --triplet=arm64-linux testport[core]:x64-linux.
#177

[dg0yt]

Right, already works as intended by Microsoft. Cf. microsoft/vcpkg#51325 for a recent discussion.
TLDNR: If you don't want default-features for a particular package:triplet, be explicit in your install command.