CXX-3180 address misc. mingw-w64 GCC compatibility issues (#1512)

eramongodb · web-flow · commit 236991974e13 · 2025-12-01T09:31:16.000-06:00
* Extend BSONCXX_PRIVATE_IF_GCC to support mingw-w64 GCC targeting Windows
* Avoid not-unique function address issues when linking with mingw-w64
* Use consistent error message for scoped_bson bson_concat failure
* Fix implicit instantiation of v1::array::view via scoped_bson header
* Remove stray export macros on inline function definitions
* Address StringMaker&lt;T&gt;::convert() implicit instantiation issues
* Use _WIN32 instead of _MSC_VER for &lt;sys/wait.h&gt;
* Avoid C99 format specifier compatibility issues with mingw-w64 GCC
diff --git a/examples/api/bsoncxx/examples/oid/basic_usage.cpp b/examples/api/bsoncxx/examples/oid/basic_usage.cpp
@@ -40,7 +40,8 @@ void example() {
         {
             std::time_t time = oid.get_time_t();
             char str[sizeof("YYYY-MM-DD HH:MM:SS")];
-            EXPECT(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);
+            // Avoid %F and %T for mingw-w64 GCC compatibiility.
+            EXPECT(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);
             EXPECT(std::string(str) == "1970-01-01 00:00:00");
         }
 
@@ -61,7 +62,8 @@ void example() {
         {
             std::time_t time = oid.get_time_t();
             char str[sizeof("YYYY-MM-DD HH:MM:SS")];
-            EXPECT(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);
+            // Avoid %F and %T for mingw-w64 GCC compatibiility.
+            EXPECT(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);
             EXPECT(std::string(str) == "2000-01-01 23:59:59");
         }
 
diff --git a/examples/api/runner.cpp b/examples/api/runner.cpp
@@ -43,13 +43,13 @@
 
 #include <examples/macros.hh>
 
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
 
 #include <unistd.h>
 
 #include <sys/wait.h>
 
-#endif // !defined(_MSC_VER)
+#endif // !defined(_WIN32)
 
 namespace {
 
@@ -119,7 +119,7 @@ class runner_type {
 
     action run_forking_components() {
         if (use_fork) {
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
             // Forking with threads is difficult and the number of components that require forking
             // are few in number. Run forking components sequentially.
             for (auto const& component : forking_components) {
@@ -167,7 +167,7 @@ class runner_type {
             }
 
             return action::succeed;
-#endif // !defined(_MSC_VER)
+#endif // !defined(_WIN32)
         }
 
         std::cout << "Skipping API examples that require forked processes" << std::endl;
@@ -484,7 +484,7 @@ void runner_register_forking_component(void (*fn)(), char const* name) {
 }
 
 int EXAMPLES_CDECL main(int argc, char** argv)
-#if defined(_MSC_VER)
+#if defined(_WIN32)
     try
 #endif
 {
@@ -539,7 +539,7 @@ int EXAMPLES_CDECL main(int argc, char** argv)
 
     return runner.run(); // Return directly from forked processes.
 }
-#if defined(_MSC_VER)
+#if defined(_WIN32)
 // Avoid popup dialog boxes or completely-absent CLI error messages on Windows.
 catch (std::exception const& ex) {
     std::cerr << "API runner failed due to uncaught exception: " << ex.what() << std::endl;
diff --git a/src/bsoncxx/include/bsoncxx/v1/detail/macros.hpp b/src/bsoncxx/include/bsoncxx/v1/detail/macros.hpp
@@ -119,11 +119,16 @@
 //
 // MSVC: supports inline variables since 19.12 (with /std:c++latest), but behavior is broken for static data members
 // (multiple definitions) until 19.20 even when __cpp_inline_variables is defined.
+//
+// mingw-w64: this is an ancient bug/issue: https://sourceware.org/bugzilla/show_bug.cgi?id=9687. Use the
+// Windows-specific [[gnu::selectany]] attribute instead, which provides link-once semantics for global variables.
 #if (                                                                                                      \
     !defined(_MSC_VER) &&                                                                                  \
     (__cplusplus >= 201703L || (defined(__cpp_inline_variables) && __cpp_inline_variables >= 201606L))) || \
     (defined(_MSC_VER) && _MSC_VER >= 1920 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
 #define BSONCXX_PRIVATE_INLINE_CXX17 inline
+#elif defined(__MINGW32__)
+#define BSONCXX_PRIVATE_INLINE_CXX17 [[gnu::selectany]]
 #else
 #define BSONCXX_PRIVATE_INLINE_CXX17                                                                   \
     BSONCXX_PRIVATE_IF_GCC([[gnu::weak]])                                                              \
diff --git a/src/bsoncxx/include/bsoncxx/v_noabi/bsoncxx/string/view_or_value.hpp b/src/bsoncxx/include/bsoncxx/v_noabi/bsoncxx/string/view_or_value.hpp
@@ -48,7 +48,7 @@ class view_or_value : public bsoncxx::v_noabi::view_or_value<stdx::string_view,
     ///
     /// Default constructor, equivalent to using an empty string.
     ///
-    BSONCXX_ABI_EXPORT_CDECL() view_or_value() = default;
+    view_or_value() = default;
 
     ///
     /// Construct a string::view_or_value using a null-terminated const char *.
diff --git a/src/bsoncxx/test/v1/element/view.cpp b/src/bsoncxx/test/v1/element/view.cpp
@@ -19,7 +19,6 @@
 #include <bsoncxx/test/v1/document/view.hh>
 #include <bsoncxx/test/v1/exception.hh>
 #include <bsoncxx/test/v1/types/value.hh>
-#include <bsoncxx/test/v1/types/view.hh>
 
 #include <cstdint>
 #include <cstring>
diff --git a/src/bsoncxx/test/v1/oid.cpp b/src/bsoncxx/test/v1/oid.cpp
@@ -147,7 +147,8 @@ TEST_CASE("basic", "[bsoncxx][v1][oid]") {
         {
             std::time_t time = o.get_time_t();
             char str[sizeof("YYYY-MM-DD HH:MM:SS")];
-            CHECK(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);
+            // Avoid %F and %T for mingw-w64 GCC compatibiility.
+            CHECK(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);
             CHECK(std::string(str) == "1970-01-01 00:00:00");
         }
 
@@ -172,7 +173,8 @@ TEST_CASE("basic", "[bsoncxx][v1][oid]") {
         {
             std::time_t time = o.get_time_t();
             char str[sizeof("YYYY-MM-DD HH:MM:SS")];
-            CHECK(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);
+            // Avoid %F and %T for mingw-w64 GCC compatibiility.
+            CHECK(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);
             CHECK(std::string(str) == "2000-01-01 23:59:59");
         }
 
diff --git a/src/bsoncxx/test/v1/types/value.hh b/src/bsoncxx/test/v1/types/value.hh
@@ -18,7 +18,7 @@
 
 //
 
-#include <bsoncxx/test/v1/types/view.hh>
+#include <bsoncxx/test/v1/types/view.hh> // IWYU pragma: export
 
 #include <catch2/catch_tostring.hpp>
 
diff --git a/src/bsoncxx/test/v_noabi/array.cpp b/src/bsoncxx/test/v_noabi/array.cpp
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <bsoncxx/test/v1/array/view.hh>
+
 #include <algorithm>
 
 #include <bsoncxx/array/view.hpp>
diff --git a/src/bsoncxx/test/v_noabi/oid.cpp b/src/bsoncxx/test/v_noabi/oid.cpp
@@ -74,9 +74,12 @@ parsed_oid parse_oid(oid const& oid) {
 }
 
 void compare_string(std::time_t const& t, bsoncxx::stdx::string_view time) {
-    char time_str[48] = {};
-    CHECK(0 != (std::strftime(time_str, sizeof(time_str), "%b %e, %Y %H:%M:%S UTC", std::gmtime(&t))));
-    CHECK(time_str == time);
+    char time_str[48];
+
+    // Avoid %e for MSVCRT-based mingw-w64 GCC compatibility.
+    REQUIRE(0 != (strftime(time_str, sizeof(time_str), "%b %d, %Y %H:%M:%S UTC", std::gmtime(&t))));
+
+    REQUIRE(time_str == time);
 }
 
 TEST_CASE("basic", "[bsoncxx][v_noabi][oid]") {
@@ -96,10 +99,10 @@ TEST_CASE("basic", "[bsoncxx][v_noabi][oid]") {
         REQUIRE(tc == 0x80000000);
         REQUIRE(td == 0xFFFFFFFF);
 
-        compare_string(ta, "Jan  1, 1970 00:00:00 UTC");
+        compare_string(ta, "Jan 01, 1970 00:00:00 UTC");
         compare_string(tb, "Jan 19, 2038 03:14:07 UTC");
         compare_string(tc, "Jan 19, 2038 03:14:08 UTC");
-        compare_string(td, "Feb  7, 2106 06:28:15 UTC");
+        compare_string(td, "Feb 07, 2106 06:28:15 UTC");
     }
 
     // Ensure that after a new process is created through a fork() or similar process creation operation, the "random
@@ -138,7 +141,8 @@ TEST_CASE("basic", "[bsoncxx][v_noabi][oid]") {
         {
             std::time_t time = o.get_time_t();
             char str[sizeof("YYYY-MM-DD HH:MM:SS")];
-            CHECK(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);
+            // Avoid %F and %T for mingw-w64 GCC compatibiility.
+            CHECK(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);
             CHECK(std::string(str) == "2000-01-01 23:59:59");
         }
 
diff --git a/src/mongocxx/include/mongocxx/v_noabi/mongocxx/client_session.hpp b/src/mongocxx/include/mongocxx/v_noabi/mongocxx/client_session.hpp
@@ -68,7 +68,7 @@ class client_session {
     MONGOCXX_ABI_EXPORT_CDECL(client_session&) operator=(client_session&&) noexcept;
 
     client_session(client_session const&) = delete;
-    MONGOCXX_ABI_EXPORT_CDECL(client_session&) operator=(client_session const&) = delete;
+    client_session& operator=(client_session const&) = delete;
 
     ///
     /// Ends and destroys the session.
diff --git a/src/mongocxx/include/mongocxx/v_noabi/mongocxx/collection.hpp b/src/mongocxx/include/mongocxx/v_noabi/mongocxx/collection.hpp
@@ -239,8 +239,9 @@ class collection {
     /// - @ref mongocxx::v_noabi::bulk_write
     /// - https://www.mongodb.com/docs/manual/core/bulk-write-operations/
     ///
-    MONGOCXX_ABI_EXPORT_CDECL(bsoncxx::v_noabi::stdx::optional<result::bulk_write>)
-    write(model::write const& write, options::bulk_write const& options = options::bulk_write()) {
+    bsoncxx::v_noabi::stdx::optional<result::bulk_write> write(
+        model::write const& write,
+        options::bulk_write const& options = options::bulk_write()) {
         return create_bulk_write(options).append(write).execute();
     }
 
@@ -267,8 +268,7 @@ class collection {
     /// - @ref mongocxx::v_noabi::bulk_write
     /// - https://www.mongodb.com/docs/manual/core/bulk-write-operations/
     ///
-    MONGOCXX_ABI_EXPORT_CDECL(bsoncxx::v_noabi::stdx::optional<result::bulk_write>)
-    write(
+    bsoncxx::v_noabi::stdx::optional<result::bulk_write> write(
         client_session const& session,
         model::write const& write,
         options::bulk_write const& options = options::bulk_write()) {
diff --git a/src/mongocxx/include/mongocxx/v_noabi/mongocxx/index_view.hpp b/src/mongocxx/include/mongocxx/v_noabi/mongocxx/index_view.hpp
@@ -47,7 +47,7 @@ class index_view {
     MONGOCXX_ABI_EXPORT_CDECL() ~index_view();
 
     index_view(index_view const&) = delete;
-    MONGOCXX_ABI_EXPORT_CDECL(index_view&) operator=(index_view const&) = delete;
+    index_view& operator=(index_view const&) = delete;
 
     ///
     /// Returns a cursor over all the indexes.
diff --git a/src/mongocxx/include/mongocxx/v_noabi/mongocxx/read_preference.hpp b/src/mongocxx/include/mongocxx/v_noabi/mongocxx/read_preference.hpp
@@ -328,8 +328,7 @@ class read_preference {
     ///
     /// @return A hedge document if one was set.
     ///
-    MONGOCXX_DEPRECATED MONGOCXX_ABI_EXPORT_CDECL(bsoncxx::v_noabi::stdx::optional<bsoncxx::v_noabi::document::view> const)
-    hedge() const {
+    MONGOCXX_DEPRECATED bsoncxx::v_noabi::stdx::optional<bsoncxx::v_noabi::document::view> const hedge() const {
         bsoncxx::v_noabi::stdx::optional<bsoncxx::v_noabi::document::view> ret;
         if (auto const opt = _rp.hedge()) {
             ret.emplace(*opt);
diff --git a/src/mongocxx/lib/mongocxx/private/scoped_bson.cpp b/src/mongocxx/lib/mongocxx/private/scoped_bson.cpp
@@ -47,7 +47,7 @@ scoped_bson& scoped_bson::operator+=(scoped_bson_view other) {
         }
 
         bson_destroy(&bson);
-        throw std::logic_error{"mongocxx::scoped_bson::operator+=: bson_new_from_data failed"};
+        throw std::logic_error{"mongocxx::scoped_bson::operator+=: bson_concat failed"};
     }
 
     // Compatible allocator: avoid an unnecessary copy by reusing the underlying BSON data.
diff --git a/src/mongocxx/test/private/scoped_bson.cpp b/src/mongocxx/test/private/scoped_bson.cpp
@@ -16,6 +16,8 @@
 
 //
 
+#include <bsoncxx/test/v1/document/value.hh>
+
 #include <cstdint>
 #include <stdexcept>
 #include <utility>
@@ -430,6 +432,8 @@ TEST_CASE("concat", "[mongocxx][private][scoped_bson]") {
             auto const data = bsoncxx::make_unique_for_overwrite<char[]>(size);
             auto const big_string = bsoncxx::v1::stdx::string_view{data.get(), size};
 
+            REQUIRE(data);
+
             std::memset(data.get(), 'x', size - 1u);
             data[size - 1u] = '\0';
 
@@ -513,32 +517,55 @@ TEST_CASE("concat", "[mongocxx][private][scoped_bson]") {
     }
 
     SECTION("deleter") {
+        auto& noop_deleter = bsoncxx::v1::document::value::noop_deleter;
+        auto& bson_free = ::bson_free;
+
         scoped_bson const x1{R"({"x": 1})"};
         scoped_bson const x2{R"({"x": 2})"};
         scoped_bson const x1x2{R"({"x": 1, "x": 2})"};
 
         std::uint8_t data[] = {5, 0, 0, 0, 0}; // {}
-        scoped_bson doc{bsoncxx::v1::document::value{data, &bsoncxx::v1::document::value::noop_deleter}};
+        scoped_bson doc{bsoncxx::v1::document::value{data, &noop_deleter}};
 
         doc += x1; // noop_deleter -> bson_free
 
         CHECK(doc.view() == x1.view());
 
+#if defined(__MINGW32__)
+        {
+            // Linking with mingw-w64 does not guarantee a unique address for `bson_free`.
+            // Negative-test that the deleter is *no longer* `noop_deleter` instead.
+            (void)bson_free;
+            auto const deleter_ptr = doc.value().get_deleter().target<decltype(&noop_deleter)>();
+            CHECK_FALSE(deleter_ptr);
+        }
+#else
         {
             auto const deleter_ptr = doc.value().get_deleter().target<decltype(&bson_free)>();
             REQUIRE(deleter_ptr);
             CHECK(*deleter_ptr == &bson_free);
         }
+#endif
 
         doc += x2; // bson_free -> bson_free
 
         CHECK(doc.view() == x1x2.view());
 
+#if defined(__MINGW32__)
+        {
+            // Linking with mingw-w64 does not guarantee a unique address for `bson_free`.
+            // Negative-test that the deleter is *no longer* `noop_deleter` instead.
+            (void)bson_free;
+            auto const deleter_ptr = doc.value().get_deleter().target<decltype(&noop_deleter)>();
+            CHECK_FALSE(deleter_ptr);
+        }
+#else
         {
             auto const deleter_ptr = doc.value().get_deleter().target<decltype(&bson_free)>();
             REQUIRE(deleter_ptr);
             CHECK(*deleter_ptr == &bson_free);
         }
+#endif
     }
 }
 
diff --git a/src/mongocxx/test/private/scoped_bson.hh b/src/mongocxx/test/private/scoped_bson.hh
@@ -18,6 +18,7 @@
 
 //
 
+#include <bsoncxx/test/v1/array/view.hh>    // IWYU pragma: keep: Catch::StringMaker<bsoncxx::v1::array::view>
 #include <bsoncxx/test/v1/document/view.hh> // IWYU pragma: keep: Catch::StringMaker<bsoncxx::v1::document::view>
 
 #include <string>
diff --git a/src/mongocxx/test/subprocess.cpp b/src/mongocxx/test/subprocess.cpp
@@ -21,7 +21,7 @@
 
 #include <catch2/catch_test_macros.hpp>
 
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
 
 #include <cstdlib>  // exit(), strsignal(), etc.
 #include <string.h> // strsignal()
@@ -112,7 +112,7 @@ int subprocess(std::function<void()> fn, bool* is_signal_ptr) {
 } // namespace test
 } // namespace mongocxx
 
-#endif // !defined(_MSC_VER)
+#endif // !defined(_WIN32)
 
 TEST_CASE("counter", "[mongocxx][test][subprocess]") {
     std::atomic_int counter{0};
@@ -166,7 +166,7 @@ TEST_CASE("exception", "[mongocxx][test][subprocess]") {
 }
 
 TEST_CASE("unknown exception", "[mongocxx][test][subprocess]") {
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
     auto is_signal = false;
     auto const ret = mongocxx::test::subprocess(
         [] {
@@ -185,5 +185,5 @@ TEST_CASE("unknown exception", "[mongocxx][test][subprocess]") {
 
     CHECK_SUBPROCESS([] {});
 
-#endif // !defined(_MSC_VER)
+#endif // !defined(_WIN32)
 }
diff --git a/src/mongocxx/test/subprocess.hh b/src/mongocxx/test/subprocess.hh
@@ -33,7 +33,7 @@ namespace test {
 // (`*is_signal_ptr` is `true`) .
 int subprocess(std::function<void()> fn, bool* is_signal_ptr = nullptr);
 
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
 
 #define CHECK_SUBPROCESS(...)                                    \
     if (1) {                                                     \
@@ -54,7 +54,7 @@ int subprocess(std::function<void()> fn, bool* is_signal_ptr = nullptr);
 #define CHECK_SUBPROCESS(...) SKIP("mongocxx::test::subprocess() is not supported")
 #define CHECK_FALSE_SUBPROCESS(...) SKIP("mongocxx::test::subprocess() is not supported")
 
-#endif // !defined(_MSC_VER)
+#endif // !defined(_WIN32)
 
 } // namespace test
 } // namespace mongocxx
diff --git a/src/mongocxx/test/v1/instance.cpp b/src/mongocxx/test/v1/instance.cpp

Original file line number	Diff line number	Diff line change
`@@ -40,7 +40,8 @@ void example() {`
`40`	`40`	`{`
`41`	`41`	`std::time_t time = oid.get_time_t();`
`42`	`42`	`char str[sizeof("YYYY-MM-DD HH:MM:SS")];`
`43`		`- EXPECT(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);`
	`43`	`+ // Avoid %F and %T for mingw-w64 GCC compatibiility.`
	`44`	`+ EXPECT(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);`
`44`	`45`	`EXPECT(std::string(str) == "1970-01-01 00:00:00");`
`45`	`46`	`}`
`46`	`47`
`@@ -61,7 +62,8 @@ void example() {`
`61`	`62`	`{`
`62`	`63`	`std::time_t time = oid.get_time_t();`
`63`	`64`	`char str[sizeof("YYYY-MM-DD HH:MM:SS")];`
`64`		`- EXPECT(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);`
	`65`	`+ // Avoid %F and %T for mingw-w64 GCC compatibiility.`
	`66`	`+ EXPECT(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);`
`65`	`67`	`EXPECT(std::string(str) == "2000-01-01 23:59:59");`
`66`	`68`	`}`
`67`	`69`
Original file line number	Diff line number	Diff line change
`@@ -147,7 +147,8 @@ TEST_CASE("basic", "[bsoncxx][v1][oid]") {`
`147`	`147`	`{`
`148`	`148`	`std::time_t time = o.get_time_t();`
`149`	`149`	`char str[sizeof("YYYY-MM-DD HH:MM:SS")];`
`150`		`- CHECK(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);`
	`150`	`+ // Avoid %F and %T for mingw-w64 GCC compatibiility.`
	`151`	`+ CHECK(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);`
`151`	`152`	`CHECK(std::string(str) == "1970-01-01 00:00:00");`
`152`	`153`	`}`
`153`	`154`
`@@ -172,7 +173,8 @@ TEST_CASE("basic", "[bsoncxx][v1][oid]") {`
`172`	`173`	`{`
`173`	`174`	`std::time_t time = o.get_time_t();`
`174`	`175`	`char str[sizeof("YYYY-MM-DD HH:MM:SS")];`
`175`		`- CHECK(std::strftime(str, sizeof(str), "%F %T", std::gmtime(&time)) == sizeof(str) - 1u);`
	`176`	`+ // Avoid %F and %T for mingw-w64 GCC compatibiility.`
	`177`	`+ CHECK(std::strftime(str, sizeof(str), "%Y-%m-%d %H:%M:%S", std::gmtime(&time)) == sizeof(str) - 1u);`
`176`	`178`	`CHECK(std::string(str) == "2000-01-01 23:59:59");`
`177`	`179`	`}`
`178`	`180`