Review: a file added to a subproject or an overlay re-runs the installation; uic, rcc and lrelease refuse two inputs with one output name; the Widgets fixture runs on macOS

Found by a review of the branch against mcpp's SPEC-007. The added-file criterion fails with the watch removed and passes with it.

Author: Sunrisepeak

.github/scripts/check-deps-and-qt.sh

@@ -15,6 +15,7 @@ ROOT=$(cd "$(dirname "$0")/../.." && pwd)
 fail() { echo "FAIL: $*"; exit 1; }
 
 is_windows() { case "$(uname -s)" in MINGW*|MSYS*|CYGWIN*) return 0 ;; *) return 1 ;; esac; }
+is_macos() { [ "$(uname -s)" = Darwin ]; }
 
 # The stamp an installation action leaves: the file mcpp writes when a `check`
 # action's command succeeds. Its modification time is the criterion for "the
@@ -104,6 +105,17 @@ cmake_consumer() {
     # And not again: the engine moves the stamp past the input that changed
     # (mcpp's SPEC-007 R3.5).
     assert_not_rerun "$(stamp_of deps-cmake)"
+
+    # A file ADDED to the subproject is an input too: the build program watches
+    # the tree, so the next plan names it and the installation runs again.
+    trap 'rm -f "$ROOT/tests/cmake-consumer/greet/added.txt"' RETURN
+    touch -r "$(stamp_of deps-cmake)" target/ci/before-added-file
+    sleep 1
+    echo added > greet/added.txt
+    "$MCPP" build > target/ci/added-build.log 2>&1 || { cat target/ci/added-build.log; fail "the build after adding a file failed"; }
+    [ -n "$(find "$(stamp_of deps-cmake)" -newer target/ci/before-added-file)" ] ||
+        fail "a file added to the subproject did not re-run its installation"
+    echo "ok: a file added to the subproject re-ran its installation"
 }
 
 qt_consumer() {
@@ -124,6 +136,10 @@ qt_widgets_consumer() {
     QT_QPA_PLATFORM=offscreen "$MCPP" run | tee run.log
     grep -q "^qt-widgets-consumer: platform offscreen, label 'made by uic'$" run.log ||
         fail "the platform plugin or the uic form did not reach the program"
+    if is_macos; then
+        find target -path '*/bin/platforms/libqoffscreen.dylib' | grep -q . ||
+            fail "no platforms/libqoffscreen.dylib was deployed beside the program"
+    fi
     if is_windows; then
         QT_QPA_PLATFORM=offscreen run_directly qt-widgets-consumer | tee direct.log
         grep -q "^qt-widgets-consumer: platform offscreen" direct.log ||

.github/workflows/ci.yml

@@ -2334,6 +2334,8 @@ jobs:
       - name: rules-qt runs moc, rcc and lrelease, with the SDK from xim:qt
         run: bash .github/scripts/check-deps-and-qt.sh qt-consumer
 
+      # Windows and macOS: QtGui's dependencies are the system's there. On Linux
+      # QtGui loads libdbus, which the ecosystem does not publish, so the Linux
+      # job runs the console fixture only.
       - name: rules-qt builds a Widgets program with a .ui form, and it runs offscreen
-        if: runner.os == 'Windows'
         run: bash .github/scripts/check-deps-and-qt.sh qt-widgets-consumer

deps/cmake.cppm

@@ -146,6 +146,7 @@ inline prefix use(const options& opt) {
         for (auto const& x : opt.cache_args) a.arg(x.c_str());
         a.input(tool.c_str());
         for (auto const& f : mcpp::deps::files_under(source)) a.input(f.c_str());
+        mcpp::deps::watch_tree(source);
         a.output(stamp.c_str());
         a.output_dir(p.root.c_str());
         a.submit();

deps/deps.cppm

@@ -123,6 +123,16 @@ inline std::vector<std::string> files_under(const std::filesystem::path& dir) {
     return out;
 }
 
+// Re-runs the build program when the SET of files under `dir` changes, so a
+// file added to a subproject or an overlay becomes an input of the action the
+// next plan declares; `files_under` names the files that exist now. The
+// pattern is relative to the package root, as `rerun_if_changed_glob` takes it.
+inline void watch_tree(const std::filesystem::path& dir) {
+    const auto rel = dir.lexically_relative(std::filesystem::path(mcpp::manifest_dir()));
+    const std::string pattern = (rel.empty() ? std::string(".") : rel.generic_string()) + "/**";
+    mcpp::rerun_if_changed_glob(pattern.c_str());
+}
+
 // The file a library name denotes under `lib_dir`. A name that already carries
 // an extension is a file name and is taken as written; otherwise the target's
 // convention decides: `<name>.lib` on Windows (an import library and a static

deps/vcpkg.cppm

@@ -256,10 +256,14 @@ inline prefix use(const options& opt = {}) {
         if (fs::is_regular_file(configFile, ec)) a.input(mcpp::deps::generic(configFile).c_str());
         // An overlay's files are inputs: a changed patch or triplet is a
         // different installation.
-        for (auto const& d : overlayTriplets)
+        for (auto const& d : overlayTriplets) {
             for (auto const& f : mcpp::deps::files_under(d)) a.input(f.c_str());
-        for (auto const& d : overlayPorts)
+            mcpp::deps::watch_tree(d);
+        }
+        for (auto const& d : overlayPorts) {
             for (auto const& f : mcpp::deps::files_under(d)) a.input(f.c_str());
+            mcpp::deps::watch_tree(d);
+        }
         a.output(stamp.c_str());
         a.output_dir(p.root.c_str());
         a.submit();

rules/qt.cppm

@@ -425,15 +425,21 @@ inline bool compile(options opt = {}) {
         headers.clear();
         inlineMoc.clear();
     }
-    std::map<std::string, fs::path> mocNames;
+    // EVERY GENERATED NAME HAS ONE SOURCE. Each generator names its output
+    // after the input's stem, in one directory, so two inputs with one stem in
+    // different directories would be two actions writing one file; refused
+    // naming both, for moc, uic, rcc and lrelease alike.
+    std::map<std::string, fs::path> claimed;
+    auto claim = [&](const std::string& outName, const fs::path& in) -> bool {
+        auto [it, fresh] = claimed.try_emplace(outName, in);
+        if (fresh) return true;
+        std::cerr << std::format("{}: two files produce `{}`: {} and {}. Generated files are "
+                                 "named after the input's stem; rename one.\n",
+                                 who, outName, generic(it->second), generic(in));
+        return false;
+    };
     auto mocOne = [&](const fs::path& in, const std::string& outName) -> bool {
-        auto [it, fresh] = mocNames.try_emplace(outName, in);
-        if (!fresh) {
-            std::cerr << std::format("{}: two files produce `{}`: {} and {}. moc outputs are named "
-                                     "after the file's stem; rename one.\n",
-                                     who, outName, generic(it->second), generic(in));
-            return false;
-        }
+        if (!claim(outName, in)) return false;
         const std::string out = generic(gen / outName);
         const std::string dep = out + ".d";
         const std::string src = generic(in);
@@ -464,6 +470,7 @@ inline bool compile(options opt = {}) {
             forms.clear();
         }
         for (auto const& f : forms) {
+            if (!claim("ui_" + fs::path(f).stem().string() + ".h", detail::absolute_from_root(f))) return false;
             const std::string in  = generic(detail::absolute_from_root(f));
             const std::string out = generic(gen / ("ui_" + fs::path(f).stem().string() + ".h"));
             const std::string id  = "qt:uic:" + fs::path(f).stem().string();
@@ -490,6 +497,7 @@ inline bool compile(options opt = {}) {
         for (auto const& r : resources) {
             const fs::path qrc = detail::absolute_from_root(r);
             const std::string stem = qrc.stem().string();
+            if (!claim("qrc_" + stem + ".cpp", qrc)) return false;
             const std::string in  = generic(qrc);
             const std::string out = generic(gen / ("qrc_" + stem + ".cpp"));
             const std::string id  = "qt:rcc:" + stem;
@@ -532,6 +540,7 @@ inline bool compile(options opt = {}) {
         for (auto const& t : ts) {
             const fs::path file = detail::absolute_from_root(t);
             const std::string stem = file.stem().string();
+            if (!claim(stem + ".qm", file)) return false;
             const std::string in = generic(file);
             const fs::path qmDir = opt.i18n.out_dir.empty() ? gen / "translations"
                                                             : detail::absolute_from_root(opt.i18n.out_dir);

tests/qt-widgets-consumer/mcpp.toml

@@ -25,9 +25,9 @@ plugins = { path = "../..", features = ["rules-qt-xim"], host-module = true }
 [build]
 sources = ["src/*.cpp", "ui/*.ui"]
 
-# Built and run on Windows by CI; on Linux QtGui needs libdbus, which the
-# ecosystem does not publish. The Linux runtime contract below states what a
-# Linux build of it will need once it does.
+# Built and run on Windows and macOS by CI; on Linux QtGui needs libdbus, which
+# the ecosystem does not publish. The Linux runtime contract below is what a
+# Linux build of it states.
 #
 # Qt's Linux libraries load the shared libstdc++ (`libstdc++.so.6`), so a
 # program that links them uses the toolchain's shared C++ runtime rather than