fix: scope warning suppression and keep consumer macros clean

.github/workflows/cmake.yml

@@ -2,9 +2,9 @@ name: CMake
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "master", "dev" ]
   pull_request:
-    branches: [ "master" ]
+    branches: [ "master", "dev" ]
 
 jobs:
   build:
@@ -20,6 +20,10 @@ jobs:
     steps:
     - uses: actions/checkout@v4
 
+    - name: Check Clang warning hygiene
+      if: runner.os != 'Windows'
+      run: python3 scripts/check-warning-hygiene.py --compiler clang++
+
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. 
       run: bash ${{github.workspace}}/scripts/build-all.sh config ${{github.workspace}}

include/zeroerr/fuzztest.h

@@ -21,15 +21,15 @@
 ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH
 
 #define ZEROERR_CREATE_FUZZ_TEST_FUNC(function, name, ...)                                  \
+    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                                   \
     static void                     function(zeroerr::TestContext*);                        \
     static zeroerr::detail::regTest ZEROERR_NAMEGEN(_zeroerr_reg)(                          \
         {name, __FILE__, __LINE__, function, {__VA_ARGS__}}, zeroerr::TestType::fuzz_test); \
+    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP                                                    \
     static void function(ZEROERR_UNUSED(zeroerr::TestContext* _ZEROERR_TEST_CONTEXT))
 
 #define FUZZ_TEST_CASE(...) \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH \
-    ZEROERR_CREATE_FUZZ_TEST_FUNC(ZEROERR_NAMEGEN(_zeroerr_testcase), __VA_ARGS__) \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+    ZEROERR_CREATE_FUZZ_TEST_FUNC(ZEROERR_NAMEGEN(_zeroerr_testcase), __VA_ARGS__)
 
 #define FUZZ_FUNC(func) zeroerr::FuzzFunction(func, _ZEROERR_TEST_CONTEXT)
 
@@ -234,4 +234,4 @@ std::vector<T> ReadCorpusFromDir(std::string dir);
 }  // namespace zeroerr
 
 
-ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+ZEROERR_SUPPRESS_COMMON_WARNINGS_POP

include/zeroerr/internal/config.h

@@ -223,6 +223,17 @@
 // == COMPILER WARNINGS ============================================================================
 // =================================================================================================
 
+// Clang warning groups vary across upstream, Apple and Android releases.
+// Test support instead of emitting an unknown diagnostic from the suppression itself.
+#define ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
+#if ZEROERR_CLANG && !ZEROERR_ICC
+#if __has_warning("-Wvariadic-macro-arguments-omitted")
+#undef ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
+#define ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED \
+    ZEROERR_CLANG_SUPPRESS_WARNING("-Wvariadic-macro-arguments-omitted")
+#endif
+#endif
+
 // both the header and the implementation suppress all of these,
 // so it only makes sense to aggregate them like so
 #define ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                                      \
@@ -233,7 +244,7 @@
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wmissing-prototypes")                                         \
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wc++98-compat")                                               \
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wc++98-compat-pedantic")                                      \
-    ZEROERR_CLANG_SUPPRESS_WARNING("-Wvariadic-macro-arguments-omitted")                           \
+    ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED                                                        \
                                                                                                    \
     ZEROERR_GCC_SUPPRESS_WARNING_PUSH                                                              \
     ZEROERR_GCC_SUPPRESS_WARNING("-Wunknown-pragmas")                                              \
@@ -304,7 +315,7 @@
 
 #define ZEROERR_SUPPRESS_VARIADIC_MACRO                                             \
     ZEROERR_CLANG_SUPPRESS_WARNING_WITH_PUSH("-Wgnu-zero-variadic-macro-arguments") \
-    ZEROERR_CLANG_SUPPRESS_WARNING_WITH_PUSH("-Wvariadic-macro-arguments-omitted")
+    ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
 
 #define ZEROERR_SUPPRESS_VARIADIC_MACRO_POP ZEROERR_CLANG_SUPPRESS_WARNING_POP
 

include/zeroerr/log.h

@@ -186,11 +186,11 @@ extern int _ZEROERR_G_VERBOSE;
 #undef ZEROERR_G_CONTEXT_SCOPE
 #endif
 
-#define ZEROERR_G_CONTEXT_SCOPE(x)                                 \
-    if (x) {                                                       \
-        for (auto* i : zeroerr::_ZEROERR_G_CONTEXT_SCOPE_VECTOR) { \
-            i->str(std::cerr);                                     \
-        }                                                          \
+#define ZEROERR_G_CONTEXT_SCOPE(x)                                                     \
+    if (x) {                                                                           \
+        for (auto* zeroerr_context_scope : zeroerr::_ZEROERR_G_CONTEXT_SCOPE_VECTOR) { \
+            zeroerr_context_scope->str(std::cerr);                                     \
+        }                                                                              \
     }
 
 #ifdef ZEROERR_PRINT_ASSERT_DEFAULT_PRINTER

include/zeroerr/unittest.h

@@ -24,10 +24,9 @@ ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH
     zeroerr::SubCase(name, __FILE__, __LINE__, _ZEROERR_TEST_CONTEXT, {__VA_ARGS__}) \
         << [=](ZEROERR_UNUSED(zeroerr::TestContext * _ZEROERR_TEST_CONTEXT)) mutable
 
-#define SUB_CASE(...)                                                         \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                     \
-    ZEROERR_EXPAND(ZEROERR_CREATE_SUB_CASE(__VA_ARGS__))                      \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+// The caller supplies the lambda body, so no diagnostic pragma may follow
+// the lambda declarator (GCC rejects it before the opening brace).
+#define SUB_CASE(...) ZEROERR_EXPAND(ZEROERR_CREATE_SUB_CASE(__VA_ARGS__))
 
 #define ZEROERR_CREATE_TEST_CLASS(fixture, classname, funcname, name, ...)                   \
     class classname : public fixture {                                                       \

scripts/check-warning-hygiene.py

@@ -0,0 +1,72 @@
+"""Compile warning regressions with --compiler clang++, g++, or cl (developer shell)."""
+import argparse
+from pathlib import Path
+import subprocess
+import tempfile
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--compiler", required=True)
+    args = parser.parse_args()
+    root = Path(__file__).resolve().parents[1]
+    msvc = Path(args.compiler).stem.lower() == "cl"
+    version = subprocess.run([args.compiler, "--version"], capture_output=True, text=True,
+                             errors="replace")
+    clang = "clang" in version.stdout.lower()
+    with tempfile.TemporaryDirectory() as tmp:
+        source = Path(tmp) / "probe.cpp"
+        def compile_probe(code, flags, diagnostic=None):
+            source.write_text(code, encoding="utf-8")
+            if msvc:
+                command = [args.compiler, "/nologo", "/std:c++17", "/EHsc", "/utf-8", "/c",
+                           f"/I{root / 'include'}", f"/I{root}", f"/Fo{tmp}/probe.obj"]
+            else:
+                command = [args.compiler, "-std=c++17", "-fsyntax-only",
+                           f"-I{root / 'include'}", f"-I{root}"]
+            result = subprocess.run(command + flags + [str(source)], capture_output=True,
+                                    text=True, errors="replace")
+            output = result.stdout + result.stderr
+            if diagnostic is None:
+                assert result.returncode == 0, output
+            else:
+                assert result.returncode != 0 and diagnostic in output, output
+
+        # A consumer's loop variable must not collide with assertion/logging internals.
+        for header in ("zeroerr.h", "zeroerr.hpp"):
+            compile_probe(f'#include "{header}"\n'
+                          + ('' if msvc else '#pragma GCC diagnostic error "-Wshadow"\n') +
+                          'void probe() { for (int i = 0; i < 2; ++i) { REQUIRE(i >= 0); } }\n',
+                          ["/W4", "/we4456", "/we4458"] if msvc else [])
+        # Pragmas cannot separate a function/lambda declarator from its body.
+        for header in ("zeroerr/fuzztest.h", "zeroerr.hpp"):
+            compile_probe(f'#include "{header}"\n'
+                          'FUZZ_TEST_CASE("fuzz declaration") {}\n'
+                          'TEST_CASE("subcase declaration") { SUB_CASE("child") {}; }\n', [])
+        implementation = '#define ZEROERR_IMPLEMENTATION\n#include "zeroerr.hpp"\n'
+        deprecated_flags = ["/we4996"] if msvc else ["-Werror=deprecated-declarations"]
+        compile_probe(implementation, deprecated_flags)
+        compile_probe(implementation +
+                      '[[deprecated("user diagnostic")]] void old_api();\n'
+                      'void consumer() { old_api(); }\n',
+                      deprecated_flags, "4996" if msvc else "deprecated")
+        if clang:
+            prefix = '#include "zeroerr/internal/config.h"\n'
+            scoped = ('ZEROERR_SUPPRESS_VARIADIC_MACRO\n'
+                      '#define ZEROERR_PROBE(x, ...) x\n'
+                      'int value = ZEROERR_PROBE(1);\n'
+                      'ZEROERR_SUPPRESS_VARIADIC_MACRO_POP\n')
+            flags = ["-Werror=unknown-warning-option", "-Werror=gnu-zero-variadic-macro-arguments"]
+            compile_probe(prefix + scoped, flags)
+            # Leaving the scope must restore the caller's diagnostic state.
+            compile_probe(prefix + scoped +
+                          '#define USER_PROBE(x, ...) x\nint user = USER_PROBE(2);\n',
+                          flags, "variadic")
+            compile_probe(prefix + scoped +
+                          '#pragma clang diagnostic ignored "-Wzeroerr-nonexistent-warning"\n',
+                          flags, "unknown warning group")
+    print("Warning hygiene probes passed" + (" (including Clang diagnostic restoration)" if clang else ""))
+
+
+if __name__ == "__main__":
+    main()

src/log.cpp

@@ -4,6 +4,10 @@
 #include <iomanip>
 #include <unordered_set>
 
+// The implementation uses the portable CRT API. Keep this diagnostic local;
+// callers must retain their own deprecation warnings.
+ZEROERR_MSVC_SUPPRESS_WARNING_WITH_PUSH(4996)
+
 #ifdef _WIN32
 #include <windows.h>
 #else
@@ -470,3 +474,5 @@ static std::string DefaultLogCallback(const LogMessage& msg, bool colorful) {
 #undef zeroerr_color
 
 }  // namespace zeroerr
+
+ZEROERR_MSVC_SUPPRESS_WARNING_POP

src/unittest.cpp

@@ -937,7 +937,7 @@ class FailureDecorator : public Decorator {
     enum FailureType { may_fail, should_fail };
     FailureDecorator(FailureType type) : type(type) {}
 
-    bool onFinish(const TestCase& tc, TestContext& ctx) override {
+    bool onFinish(const TestCase&, TestContext& ctx) override {
         if (type == FailureType::may_fail) {
             // Treat failures as warnings so the suite can continue cleanly.
             ctx.warning_as += ctx.failed_as;

zeroerr.hpp

@@ -226,6 +226,17 @@
 // == COMPILER WARNINGS ============================================================================
 // =================================================================================================
 
+// Clang warning groups vary across upstream, Apple and Android releases.
+// Test support instead of emitting an unknown diagnostic from the suppression itself.
+#define ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
+#if ZEROERR_CLANG && !ZEROERR_ICC
+#if __has_warning("-Wvariadic-macro-arguments-omitted")
+#undef ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
+#define ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED \
+    ZEROERR_CLANG_SUPPRESS_WARNING("-Wvariadic-macro-arguments-omitted")
+#endif
+#endif
+
 // both the header and the implementation suppress all of these,
 // so it only makes sense to aggregate them like so
 #define ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                                      \
@@ -236,7 +247,7 @@
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wmissing-prototypes")                                         \
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wc++98-compat")                                               \
     ZEROERR_CLANG_SUPPRESS_WARNING("-Wc++98-compat-pedantic")                                      \
-    ZEROERR_CLANG_SUPPRESS_WARNING("-Wvariadic-macro-arguments-omitted")                           \
+    ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED                                                        \
                                                                                                    \
     ZEROERR_GCC_SUPPRESS_WARNING_PUSH                                                              \
     ZEROERR_GCC_SUPPRESS_WARNING("-Wunknown-pragmas")                                              \
@@ -307,7 +318,7 @@
 
 #define ZEROERR_SUPPRESS_VARIADIC_MACRO                                             \
     ZEROERR_CLANG_SUPPRESS_WARNING_WITH_PUSH("-Wgnu-zero-variadic-macro-arguments") \
-    ZEROERR_CLANG_SUPPRESS_WARNING_WITH_PUSH("-Wvariadic-macro-arguments-omitted")
+    ZEROERR_CLANG_SUPPRESS_VARIADIC_OMITTED
 
 #define ZEROERR_SUPPRESS_VARIADIC_MACRO_POP ZEROERR_CLANG_SUPPRESS_WARNING_POP
 
@@ -1441,9 +1452,11 @@ struct Printer {
 #else
     ZEROERR_ENABLE_IF(ZEROERR_IS_ENUM)
     print(T value, unsigned level, const char* lb, rank<0>) {
-        // enum class has no operator<< and no implicit conversion, so fall back
-        // to its underlying numeric value instead of failing to compile.
-        os << tab(level) << static_cast<typename std::underlying_type<T>::type>(value) << lb;
+        if constexpr (detail::is_streamable<std::ostream, T>::value) {
+            os << tab(level) << value << lb;
+        } else {
+            os << tab(level) << "<unprintable enum " << type(value) << ">" << lb;
+        }
     }
 #endif
 
@@ -3623,11 +3636,11 @@ extern int _ZEROERR_G_VERBOSE;
 #undef ZEROERR_G_CONTEXT_SCOPE
 #endif
 
-#define ZEROERR_G_CONTEXT_SCOPE(x)                                 \
-    if (x) {                                                       \
-        for (auto* i : zeroerr::_ZEROERR_G_CONTEXT_SCOPE_VECTOR) { \
-            i->str(std::cerr);                                     \
-        }                                                          \
+#define ZEROERR_G_CONTEXT_SCOPE(x)                                                     \
+    if (x) {                                                                           \
+        for (auto* zeroerr_context_scope : zeroerr::_ZEROERR_G_CONTEXT_SCOPE_VECTOR) { \
+            zeroerr_context_scope->str(std::cerr);                                     \
+        }                                                                              \
     }
 
 #ifdef ZEROERR_PRINT_ASSERT_DEFAULT_PRINTER
@@ -4306,10 +4319,9 @@ ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH
     zeroerr::SubCase(name, __FILE__, __LINE__, _ZEROERR_TEST_CONTEXT, {__VA_ARGS__}) \
         << [=](ZEROERR_UNUSED(zeroerr::TestContext * _ZEROERR_TEST_CONTEXT)) mutable
 
-#define SUB_CASE(...)                                                         \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                     \
-    ZEROERR_EXPAND(ZEROERR_CREATE_SUB_CASE(__VA_ARGS__))                      \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+// The caller supplies the lambda body, so no diagnostic pragma may follow
+// the lambda declarator (GCC rejects it before the opening brace).
+#define SUB_CASE(...) ZEROERR_EXPAND(ZEROERR_CREATE_SUB_CASE(__VA_ARGS__))
 
 #define ZEROERR_CREATE_TEST_CLASS(fixture, classname, funcname, name, ...)                   \
     class classname : public fixture {                                                       \
@@ -4689,15 +4701,15 @@ ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
 ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH
 
 #define ZEROERR_CREATE_FUZZ_TEST_FUNC(function, name, ...)                                  \
+    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH                                                   \
     static void                     function(zeroerr::TestContext*);                        \
     static zeroerr::detail::regTest ZEROERR_NAMEGEN(_zeroerr_reg)(                          \
         {name, __FILE__, __LINE__, function, {__VA_ARGS__}}, zeroerr::TestType::fuzz_test); \
+    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP                                                    \
     static void function(ZEROERR_UNUSED(zeroerr::TestContext* _ZEROERR_TEST_CONTEXT))
 
 #define FUZZ_TEST_CASE(...) \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_PUSH \
-    ZEROERR_CREATE_FUZZ_TEST_FUNC(ZEROERR_NAMEGEN(_zeroerr_testcase), __VA_ARGS__) \
-    ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+    ZEROERR_CREATE_FUZZ_TEST_FUNC(ZEROERR_NAMEGEN(_zeroerr_testcase), __VA_ARGS__)
 
 #define FUZZ_FUNC(func) zeroerr::FuzzFunction(func, _ZEROERR_TEST_CONTEXT)
 
@@ -4903,6 +4915,7 @@ std::vector<T> ReadCorpusFromDir(std::string dir);
 
 
 ZEROERR_SUPPRESS_COMMON_WARNINGS_POP
+
 #ifdef ZEROERR_IMPLEMENTATION
 
 
@@ -5179,6 +5192,10 @@ TerminalSize getTerminalWidth() {
 #include <iomanip>
 #include <unordered_set>
 
+// The implementation uses the portable CRT API. Keep this diagnostic local;
+// callers must retain their own deprecation warnings.
+ZEROERR_MSVC_SUPPRESS_WARNING_WITH_PUSH(4996)
+
 #ifdef _WIN32
 #include <windows.h>
 #else
@@ -5646,6 +5663,8 @@ static std::string DefaultLogCallback(const LogMessage& msg, bool colorful) {
 
 }  // namespace zeroerr
 
+ZEROERR_MSVC_SUPPRESS_WARNING_POP
+
 
 
 
@@ -6935,7 +6954,7 @@ class FailureDecorator : public Decorator {
     enum FailureType { may_fail, should_fail };
     FailureDecorator(FailureType type) : type(type) {}
 
-    bool onFinish(const TestCase& tc, TestContext& ctx) override {
+    bool onFinish(const TestCase&, TestContext& ctx) override {
         if (type == FailureType::may_fail) {
             // Treat failures as warnings so the suite can continue cleanly.
             ctx.warning_as += ctx.failed_as;