fix: support .ccm/.cxxm/.ixx module interface extensions

src/build/execute.cppm

@@ -380,8 +380,9 @@ bool sources_newer_than(const std::filesystem::path& projectRoot,
     }
     for (auto& f : mcpp::modgraph::expand_glob(projectRoot, "src/**/*")) {
         auto ext = f.extension().string();
-        if (ext != ".cppm" && ext != ".cpp" && ext != ".cc" &&
-            ext != ".cxx" && ext != ".c" && ext != ".h" && ext != ".hpp")
+        if (ext != ".cppm" && ext != ".ccm" && ext != ".cxxm" && ext != ".ixx" &&
+            ext != ".cpp" && ext != ".cc" && ext != ".cxx" && ext != ".c" &&
+            ext != ".h" && ext != ".hpp")
             continue;
         auto ft = std::filesystem::last_write_time(f, ec);
         if (ec || ft > ninjaTime) return true;

src/build/plan.cppm

@@ -155,8 +155,8 @@ std::string object_filename_for(const std::filesystem::path& src,
         return src.filename().string() + std::string(objExt);
     }
     auto stem = src.stem().string();
-    // distinguish .cppm vs .cpp by extension prefix to avoid collisions
-    return stem + (ext == ".cppm"
+    // distinguish .cppm/.ccm/.cxxm/.ixx vs .cpp/.cc/.cxx by extension prefix
+    return stem + ((ext == ".cppm" || ext == ".ccm" || ext == ".cxxm" || ext == ".ixx")
                        ? ".m" + std::string(objExt)
                        : std::string(objExt));
 }
@@ -751,7 +751,7 @@ make_plan(const mcpp::manifest::Manifest&         manifest,
     auto append_package_objects = [&](LinkUnit& lu, const std::string& packageName) {
         for (auto& cu : plan.compileUnits) {
             if (cu.packageName != packageName) continue;
-            if (cu.source.extension() == ".cppm") {
+            if (cu.providesModule) {
                 lu.objects.push_back(cu.object);
             }
         }
@@ -811,7 +811,7 @@ make_plan(const mcpp::manifest::Manifest&         manifest,
         // For binary target, also include main.cpp's object if main is present.
         for (auto& cu : plan.compileUnits) {
             if (sharedDepPackages.contains(cu.packageName)) continue;
-            if (cu.source.extension() == ".cppm") {
+            if (cu.providesModule) {
                 lu.objects.push_back(cu.object);
             }
         }

tests/e2e/152_module_extensions.sh

@@ -0,0 +1,102 @@
+#!/usr/bin/env bash
+# requires: elf gcc
+# All module interface extensions (.cppm .ccm .cxxm .ixx) must compile and link
+set -e
+
+TMP=$(mktemp -d)
+trap "rm -rf $TMP" EXIT
+
+cd "$TMP"
+"$MCPP" new moduleext > /dev/null
+cd moduleext
+
+# ---- module interface sources (one per extension) ----
+cat > src/greet.cppm <<'EOF'
+export module moduleext.greet;
+import std;
+export auto greet(std::string_view who) -> void {
+    std::println("Hello from .cppm, {}!", who);
+}
+EOF
+
+cat > src/info.ccm <<'EOF'
+export module moduleext.info;
+import std;
+export auto info(std::string_view what) -> void {
+    std::println("Info from .ccm: {}", what);
+}
+EOF
+
+cat > src/stat.cxxm <<'EOF'
+export module moduleext.stat;
+import std;
+export auto stat(int n) -> void {
+    std::println("Stat from .cxxm: {}", n);
+}
+EOF
+
+cat > src/data.ixx <<'EOF'
+export module moduleext.data;
+import std;
+export auto data(std::string_view key) -> void {
+    std::println("Data from .ixx: {}", key);
+}
+EOF
+
+# ---- consumer ----
+cat > src/main.cpp <<'EOF'
+import std;
+import moduleext.greet;
+import moduleext.info;
+import moduleext.stat;
+import moduleext.data;
+int main() {
+    greet("world");
+    info("build");
+    stat(42);
+    data("key");
+    std::println("All module extensions OK");
+    return 0;
+}
+EOF
+
+# Default glob only picks up .cppm/.cpp/.cc/.c — explicitly add .ccm/.cxxm/.ixx
+cat > mcpp.toml <<'EOF'
+[package]
+name        = "moduleext"
+version     = "0.1.0"
+[modules]
+sources = ["src/**/*.cppm", "src/**/*.ccm", "src/**/*.cxxm", "src/**/*.ixx", "src/**/*.cpp"]
+EOF
+
+# ---- build & run ----
+"$MCPP" build > build.log 2>&1 || {
+    cat build.log
+    echo "FAIL: build failed"
+    exit 1
+}
+
+out="$("$MCPP" run 2>&1)"
+[[ "$out" == *"from .cppm"* ]] || { echo "module greet (.cppm) not invoked: $out"; exit 1; }
+[[ "$out" == *"from .ccm"*  ]] || { echo "module info  (.ccm) not invoked: $out"; exit 1; }
+[[ "$out" == *"from .cxxm"* ]] || { echo "module stat  (.cxxm) not invoked: $out"; exit 1; }
+[[ "$out" == *"from .ixx"*  ]] || { echo "module data  (.ixx) not invoked: $out"; exit 1; }
+[[ "$out" == *"All module extensions OK"* ]] || { echo "final message missing: $out"; exit 1; }
+
+# ---- verify build.ninja ----
+build_ninja="$(find target -name build.ninja | head -1)"
+[[ -n "$build_ninja" ]] || { echo "no build.ninja generated"; exit 1; }
+
+# 4 BMIs
+grep -q "gcm.cache/moduleext.greet.gcm" "$build_ninja" || { echo "ninja missing greet BMI"; exit 1; }
+grep -q "gcm.cache/moduleext.info.gcm"  "$build_ninja" || { echo "ninja missing info BMI";  exit 1; }
+grep -q "gcm.cache/moduleext.stat.gcm"  "$build_ninja" || { echo "ninja missing stat BMI";  exit 1; }
+grep -q "gcm.cache/moduleext.data.gcm"  "$build_ninja" || { echo "ninja missing data BMI";  exit 1; }
+
+# 4 .m.o objects (one per module interface extension)
+grep -q "greet.m.o" "$build_ninja" || { echo "ninja missing greet.m.o (.cppm)"; exit 1; }
+grep -q "info.m.o"  "$build_ninja" || { echo "ninja missing info.m.o  (.ccm)";  exit 1; }
+grep -q "stat.m.o"  "$build_ninja" || { echo "ninja missing stat.m.o  (.cxxm)"; exit 1; }
+grep -q "data.m.o"  "$build_ninja" || { echo "ninja missing data.m.o  (.ixx)";  exit 1; }
+
+echo "OK"

tests/unit/test_module_extensions.cpp

@@ -0,0 +1,34 @@
+#include <gtest/gtest.h>
+
+import std;
+import mcpp.build.plan;
+
+using namespace mcpp::build;
+
+TEST(ModuleExtensions, CppmGetsDotMPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.cppm", ".o"), "foo.m.o");
+}
+
+TEST(ModuleExtensions, CcmGetsDotMPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.ccm", ".o"), "foo.m.o");
+}
+
+TEST(ModuleExtensions, CxxmGetsDotMPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.cxxm", ".o"), "foo.m.o");
+}
+
+TEST(ModuleExtensions, IxxGetsDotMPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.ixx", ".o"), "foo.m.o");
+}
+
+TEST(ModuleExtensions, CppHasNoPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.cpp", ".o"), "foo.o");
+}
+
+TEST(ModuleExtensions, CcHasNoPrefix) {
+    EXPECT_EQ(object_filename_for("src/foo.cc", ".o"), "foo.o");
+}
+
+TEST(ModuleExtensions, AsmKeepsFullExt) {
+    EXPECT_EQ(object_filename_for("src/foo.S", ".o"), "foo.S.o");
+}