[vcpkg] Invalid registry repository does not cause an error

[krf]

Describe the bug

When specifying an invalid registry url vcpkg will not raise an issue.

I could not find an existing ticket or other information about it (is this by design...? I would be surprised...).

Environment

• Any

To Reproduce
Steps to reproduce the behavior:

Install latest vcpkg as via documentation. My version is:

% vcpkg version
vcpkg package management program version 2025-06-02-145689e84b7637525510e2c9b4ee603fda046b56

See LICENSE.txt for license information.

Set up a new application:

mkdir newapp
cd newapp

vcpkg new --application

Modify vcpkg.json to:

{
    "dependencies": [
        "fmt"
    ]
}

Modify vcpkg-configuration to:

{
  "default-registry": {
    "kind": "git",
    "baseline": "f6729a3ac3bfdefc999aa8e3664f8014370886b8",
    "repository": "https://github.com/microsoft/vcpkg"
  },
  "registries": [
    {
      "kind": "git",
      "baseline": "f6729a3ac3bfdefc999aa8e3664f8014370886b8",
      "repository": "https://github.com/IDONOTEXIST/IDONOTEXIST",
      "packages": [
        "fmt"
      ]
    }
  ]
}

vcpkg install

Expected behavior
vcpkg errors out with something along:

"https://github.com/IDONOTEXIST/IDONOTEXIST" is inaccessible!

Actual behavior
vcpkg ignores the inaccessible repository and prints:

% vcpkg install
Fetching registry information from https://github.com/IDONOTEXIST/IDONOTEXIST (HEAD)...
fmt does not exist