[M5+] generalize nix_cmake_scan config picker

tests/nix_cmake_scan_parse.cpp

@@ -136,6 +136,69 @@ TEST_CASE("nix_cmake_scan ignores Config files with no IMPORTED targets",
     REQUIRE(r.error().code == ErrorCode::ResolutionUnknownPackage);
 }
 
+TEST_CASE("nix_cmake_scan strips a leading lib prefix when scoring",
+          "[resolver][nix_cmake_scan]") {
+    // Real layout for nixpkgs `libllvm.dev`. `libllvm` should match
+    // `LLVMConfig.cmake`'s parent dir (`llvm`) after lib-stripping
+    // and beat `polly/PollyConfig.cmake`.
+    auto store = fresh_store();
+    touch_config(store, "llvm/LLVMConfig.cmake",
+                 R"(add_library(LLVM SHARED IMPORTED))");
+    touch_config(store, "polly/PollyConfig.cmake",
+                 R"(add_library(Polly SHARED IMPORTED))");
+
+    auto r = nix_cmake_scan(store, "libllvm");
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "LLVM CONFIG REQUIRED");
+    REQUIRE(r->config_file.filename() == "LLVMConfig.cmake");
+}
+
+TEST_CASE("nix_cmake_scan picks the canonical config from a versioned dir",
+          "[resolver][nix_cmake_scan]") {
+    // Boost ships a top-level `Boost-1.89.0/BoostConfig.cmake` plus
+    // 47 modular component configs at sibling versioned dirs.
+    // After version-suffix stripping the top-level Boost should win.
+    auto store = fresh_store();
+    touch_config(store, "Boost-1.89.0/BoostConfig.cmake",
+                 R"(add_library(Boost::headers INTERFACE IMPORTED))");
+    touch_config(store, "boost_atomic-1.89.0/boost_atomic-config.cmake",
+                 R"(add_library(Boost::atomic SHARED IMPORTED))");
+    touch_config(store, "boost_filesystem-1.89.0/boost_filesystem-config.cmake",
+                 R"(add_library(Boost::filesystem SHARED IMPORTED))");
+
+    auto r = nix_cmake_scan(store, "boost");
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "Boost CONFIG REQUIRED");
+    REQUIRE(r->config_file.filename() == "BoostConfig.cmake");
+}
+
+TEST_CASE("nix_cmake_scan ignores satellite configs in multi-config stores",
+          "[resolver][nix_cmake_scan]") {
+    // Mirrors `protobuf` which ships protobuf-config.cmake plus an
+    // unrelated utf8_range-config.cmake under the same prefix tree.
+    auto store = fresh_store();
+    touch_config(store, "protobuf/protobuf-config.cmake",
+                 R"(add_library(protobuf::libprotobuf SHARED IMPORTED))");
+    touch_config(store, "utf8_range/utf8_range-config.cmake",
+                 R"(add_library(utf8_range::utf8_range SHARED IMPORTED))");
+
+    auto r = nix_cmake_scan(store, "protobuf");
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "protobuf CONFIG REQUIRED");
+}
+
+TEST_CASE("nix_cmake_scan normalizes case for spelling variants",
+          "[resolver][nix_cmake_scan]") {
+    // grpc ships `gRPCConfig.cmake` under `lib/cmake/grpc/`.
+    auto store = fresh_store();
+    touch_config(store, "grpc/gRPCConfig.cmake",
+                 R"(add_library(gRPC::grpc++ SHARED IMPORTED))");
+
+    auto r = nix_cmake_scan(store, "grpc");
+    REQUIRE(r.has_value());
+    REQUIRE(r->find_package == "gRPC CONFIG REQUIRED");
+}
+
 TEST_CASE("nix_cmake_scan scans sibling *-targets.cmake files",
           "[resolver][nix_cmake_scan]") {
     // Mirrors fmt's real on-disk layout: the *-config.cmake is empty of