[M3] add cargoxx build --no-build

tests/CMakeLists.txt

@@ -18,3 +18,4 @@ cargoxx_add_test(linkdb_overlay)
 cargoxx_add_test(codegen_flake)
 cargoxx_add_test(codegen_cmake)
 cargoxx_add_test(cmd_new)
+cargoxx_add_test(cmd_build)

tests/cmd_build.cpp

@@ -0,0 +1,176 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.cli;
+import cargoxx.manifest;
+import cargoxx.lockfile;
+import cargoxx.util;
+import std;
+
+using cargoxx::cli::cmd_build;
+using cargoxx::cli::cmd_new;
+using cargoxx::util::ErrorCode;
+namespace manifest = cargoxx::manifest;
+namespace lockfile = cargoxx::lockfile;
+
+namespace {
+
+auto fresh_dir() -> std::filesystem::path {
+    auto d = std::filesystem::temp_directory_path() /
+             std::format("cargoxx-build-test-{}", std::random_device{}());
+    std::filesystem::create_directories(d);
+    return d;
+}
+
+auto overlay_path(const std::filesystem::path& dir) -> std::filesystem::path {
+    return dir / "overlay.sqlite";
+}
+
+auto read_file(const std::filesystem::path& p) -> std::string {
+    std::ifstream in{p};
+    return std::string{std::istreambuf_iterator<char>(in), {}};
+}
+
+auto add_dep(const std::filesystem::path& root, const std::string& name,
+             const std::string& version_spec, std::vector<std::string> components = {}) {
+    auto path = root / "Cargoxx.toml";
+    auto m = manifest::parse(path);
+    REQUIRE(m.has_value());
+    m->dependencies.push_back(manifest::Dependency{
+        .name = name,
+        .version_spec = version_spec,
+        .components = std::move(components),
+    });
+    REQUIRE(manifest::write(*m, path).has_value());
+}
+
+} // namespace
+
+TEST_CASE("cmd_build generates files for a no-deps binary project",
+          "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("hello", false, parent).has_value());
+    auto root = parent / "hello";
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE(r.has_value());
+
+    REQUIRE(std::filesystem::exists(root / "flake.nix"));
+    REQUIRE(std::filesystem::exists(root / "build" / "CMakeLists.txt"));
+    REQUIRE(std::filesystem::exists(root / "Cargoxx.lock"));
+
+    auto cmake_text = read_file(root / "build" / "CMakeLists.txt");
+    REQUIRE(cmake_text.find("project(hello LANGUAGES CXX)") != std::string::npos);
+    REQUIRE(cmake_text.find("add_executable(hello_bin ../src/main.cpp)") !=
+            std::string::npos);
+
+    auto flake_text = read_file(root / "flake.nix");
+    REQUIRE(flake_text.find("description = \"hello\";") != std::string::npos);
+    REQUIRE(flake_text.find("github:NixOS/nixpkgs/nixos-unstable") != std::string::npos);
+}
+
+TEST_CASE("cmd_build generates files for a library project", "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("widget", true, parent).has_value());
+    auto root = parent / "widget";
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE(r.has_value());
+
+    auto cmake_text = read_file(root / "build" / "CMakeLists.txt");
+    REQUIRE(cmake_text.find("add_library(widget STATIC)") != std::string::npos);
+    REQUIRE(cmake_text.find("../src/lib.cppm") != std::string::npos);
+    REQUIRE(cmake_text.find("add_executable") == std::string::npos);
+}
+
+TEST_CASE("cmd_build resolves a curated dep into find_package + targets",
+          "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+    add_dep(root, "fmt", "10.2.0");
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE(r.has_value());
+
+    auto cmake_text = read_file(root / "build" / "CMakeLists.txt");
+    REQUIRE(cmake_text.find("find_package(fmt CONFIG REQUIRED)") != std::string::npos);
+    REQUIRE(cmake_text.find("fmt::fmt") != std::string::npos);
+
+    auto flake_text = read_file(root / "flake.nix");
+    REQUIRE(flake_text.find("pkgs.fmt_10") != std::string::npos);
+}
+
+TEST_CASE("cmd_build resolves a componentized dep", "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+    add_dep(root, "boost", "1.84.0", {"filesystem", "system"});
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE(r.has_value());
+
+    auto cmake_text = read_file(root / "build" / "CMakeLists.txt");
+    REQUIRE(cmake_text.find("find_package(Boost REQUIRED COMPONENTS filesystem system)") !=
+            std::string::npos);
+    REQUIRE(cmake_text.find("Boost::filesystem") != std::string::npos);
+    REQUIRE(cmake_text.find("Boost::system") != std::string::npos);
+}
+
+TEST_CASE("cmd_build synthesizes a lockfile entry per dep", "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+    add_dep(root, "fmt", "10.2.0");
+    add_dep(root, "spdlog", "1.13.0");
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE(r.has_value());
+
+    auto lock = lockfile::parse(root / "Cargoxx.lock");
+    REQUIRE(lock.has_value());
+    REQUIRE(lock->packages.size() == 3); // root + fmt + spdlog
+    REQUIRE(lock->packages[0].name == "app");
+    REQUIRE(lock->packages[0].dependencies.size() == 2);
+}
+
+TEST_CASE("cmd_build fails for an unknown dep", "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+    add_dep(root, "obscurelib", "0.0.1");
+
+    auto r = cmd_build(root, true, false, overlay_path(parent));
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::LinkdbUnknownPackage);
+}
+
+TEST_CASE("cmd_build without --no-build returns NotImplemented", "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+
+    auto r = cmd_build(root, false, false, overlay_path(parent));
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::NotImplemented);
+    // Files are still generated before the build step would run
+    REQUIRE(std::filesystem::exists(root / "flake.nix"));
+    REQUIRE(std::filesystem::exists(root / "build" / "CMakeLists.txt"));
+}
+
+TEST_CASE("cmd_build is idempotent — second run produces identical files",
+          "[cli][build]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("app", false, parent).has_value());
+    auto root = parent / "app";
+    add_dep(root, "fmt", "10.2.0");
+
+    REQUIRE(cmd_build(root, true, false, overlay_path(parent)).has_value());
+    auto first_cmake = read_file(root / "build" / "CMakeLists.txt");
+    auto first_flake = read_file(root / "flake.nix");
+    auto first_lock = read_file(root / "Cargoxx.lock");
+
+    REQUIRE(cmd_build(root, true, false, overlay_path(parent)).has_value());
+    REQUIRE(read_file(root / "build" / "CMakeLists.txt") == first_cmake);
+    REQUIRE(read_file(root / "flake.nix") == first_flake);
+    REQUIRE(read_file(root / "Cargoxx.lock") == first_lock);
+}