[M5+] add resolver::vcpkg_probe

tests/CMakeLists.txt

@@ -30,3 +30,5 @@ cargoxx_add_test(nix_cmake_scan_parse)
 cargoxx_add_test(nix_cmake_scan_live)
 cargoxx_add_test(conan_probe_parse)
 cargoxx_add_test(conan_probe_live)
+cargoxx_add_test(vcpkg_probe_parse)
+cargoxx_add_test(vcpkg_probe_live)

tests/vcpkg_probe_live.cpp

@@ -0,0 +1,43 @@
+// Network-gated integration test for resolver::vcpkg_probe.
+
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.resolver;
+import cargoxx.util;
+import std;
+
+namespace {
+
+auto network_tests_enabled() -> bool {
+    auto* env = std::getenv("CARGOXX_NETWORK_TESTS");
+    return env != nullptr && std::string_view{env} == "1";
+}
+
+} // namespace
+
+TEST_CASE("vcpkg_probe finds 'fmt' in microsoft/vcpkg",
+          "[resolver][network]") {
+    if (!network_tests_enabled()) {
+        SKIP("CARGOXX_NETWORK_TESTS != 1");
+    }
+    auto r = cargoxx::resolver::vcpkg_probe("fmt");
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package.starts_with("fmt"));
+    REQUIRE_FALSE(r->targets.empty());
+    // fmt's vcpkg port should expose at least one fmt:: target.
+    REQUIRE(std::ranges::any_of(r->targets, [](const std::string& t) {
+        return t.starts_with("fmt::");
+    }));
+}
+
+TEST_CASE("vcpkg_probe returns ResolutionUnknownPackage for a 404",
+          "[resolver][network]") {
+    if (!network_tests_enabled()) {
+        SKIP("CARGOXX_NETWORK_TESTS != 1");
+    }
+    auto r = cargoxx::resolver::vcpkg_probe(
+        "definitely_not_a_real_pkg_cargoxx_xyzzy");
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code ==
+            cargoxx::util::ErrorCode::ResolutionUnknownPackage);
+}

tests/vcpkg_probe_parse.cpp

@@ -0,0 +1,71 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.resolver;
+import cargoxx.util;
+import std;
+
+using cargoxx::resolver::parse_vcpkg_usage;
+using cargoxx::util::ErrorCode;
+
+TEST_CASE("parse_vcpkg_usage extracts find_package and a target",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(fmt provides CMake targets:
+
+    find_package(fmt CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE fmt::fmt)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "fmt CONFIG REQUIRED");
+    REQUIRE(r->targets == std::vector<std::string>{"fmt::fmt"});
+}
+
+TEST_CASE("parse_vcpkg_usage adds REQUIRED when missing", "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(spdlog CONFIG)
+    target_link_libraries(main PRIVATE spdlog::spdlog)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "spdlog CONFIG REQUIRED");
+}
+
+TEST_CASE("parse_vcpkg_usage dedupes targets", "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(boost CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE Boost::filesystem Boost::system Boost::filesystem)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->targets == std::vector<std::string>{"Boost::filesystem", "Boost::system"});
+}
+
+TEST_CASE("parse_vcpkg_usage skips generator-expression and bare-name tokens",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(qt6 CONFIG REQUIRED)
+    target_link_libraries(main PRIVATE Qt6::Core $<TARGET_NAME:Qt6::Gui> mylib)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    // mylib lacks "::", $<...> contains '$' — both excluded.
+    REQUIRE(r->targets == std::vector<std::string>{"Qt6::Core"});
+}
+
+TEST_CASE("parse_vcpkg_usage errors when no find_package directive present",
+          "[resolver][vcpkg]") {
+    auto r = parse_vcpkg_usage("nothing useful here");
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::ResolutionUnknownPackage);
+}
+
+TEST_CASE("parse_vcpkg_usage handles target_link_libraries with PUBLIC visibility",
+          "[resolver][vcpkg]") {
+    constexpr std::string_view text = R"(
+    find_package(eigen3 CONFIG REQUIRED)
+    target_link_libraries(main PUBLIC Eigen3::Eigen)
+)";
+    auto r = parse_vcpkg_usage(text);
+    REQUIRE(r.has_value());
+    REQUIRE(r->targets == std::vector<std::string>{"Eigen3::Eigen"});
+}