clang-format improvements

.clang-format

@@ -31,4 +31,3 @@ AlignConsecutiveAssignments: false
 AlignTrailingComments: true
 
 SpaceAfterCStyleCast: true
-CommentPragmas: '^ NO-FORMAT:'

.github/workflows/clang-format.yml

@@ -0,0 +1,39 @@
+name: Code Formatting
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+permissions:
+  contents: read
+
+env:
+  CLANG_VERSION: "20"
+
+jobs:
+  clang-format:
+    name: Run clang-format
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      # Install the exact clang-format binary
+      - name: Install clang-format
+        run: |
+          sudo apt install clang-format-${{ env.CLANG_VERSION }}
+
+      # Prints the version of clang-format being used
+      - name: Log clang-format version
+        run: clang-format-${{ env.CLANG_VERSION }} --version
+
+      # Runs clang-format over the repository codebase
+      - name: Check format
+        run: |
+          {
+            find include/gsl -type f
+            find tests -type f \( -name '*.cpp' -o -name '*.h' \)
+          } | xargs clang-format-${{ env.CLANG_VERSION }} --dry-run --Werror

include/gsl/algorithm

@@ -48,9 +48,7 @@ void copy(span<SrcElementType, SrcExtent> src, span<DestElementType, DestExtent>
                   "Source range is longer than target range");
 
     Expects(dest.size() >= src.size());
-    // clang-format off
-    GSL_SUPPRESS(stl.1) // NO-FORMAT: attribute
-    // clang-format on
+    GSL_SUPPRESS(stl.1)
     std::copy_n(src.data(), src.size(), dest.data());
 }
 

include/gsl/assert

@@ -93,9 +93,7 @@ namespace details
 
     typedef void(__cdecl* terminate_handler)();
 
-    // clang-format off
-    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute
-    // clang-format on
+    GSL_SUPPRESS(f.6)
     [[noreturn]] inline void __cdecl default_terminate_handler()
     {
         __fastfail(RANGE_CHECKS_FAILURE);

include/gsl/byte

@@ -82,11 +82,13 @@ namespace gsl
 {
 #if GSL_USE_STD_BYTE
 
-namespace impl {
-// impl::byte is used by gsl::as_bytes so our own code does not trigger a deprecation warning as would be the case when we used gsl::byte.
-// Users of GSL should only use gsl::byte, not gsl::impl::byte.
-using byte = std::byte;
-}
+namespace impl
+{
+    // impl::byte is used by gsl::as_bytes so our own code does not trigger a deprecation warning as
+    // would be the case when we used gsl::byte. Users of GSL should only use gsl::byte, not
+    // gsl::impl::byte.
+    using byte = std::byte;
+} // namespace impl
 
 using byte GSL_DEPRECATED("Use std::byte instead.") = std::byte;
 
@@ -100,11 +102,13 @@ enum class byte_may_alias byte : unsigned char
 {
 };
 
-namespace impl {
-// impl::byte is used by gsl::as_bytes so our own code does not trigger a deprecation warning as would be the case when we used gsl::byte.
-// Users of GSL should only use gsl::byte, not gsl::impl::byte.
-using byte = gsl::byte;
-}
+namespace impl
+{
+    // impl::byte is used by gsl::as_bytes so our own code does not trigger a deprecation warning as
+    // would be the case when we used gsl::byte. Users of GSL should only use gsl::byte, not
+    // gsl::impl::byte.
+    using byte = gsl::byte;
+} // namespace impl
 
 template <class IntegerType, std::enable_if_t<std::is_integral<IntegerType>::value, bool> = true>
 constexpr byte& operator<<=(byte& b, IntegerType shift) noexcept
@@ -170,15 +174,13 @@ constexpr IntegerType to_integer(byte b) noexcept
 
 #endif // GSL_USE_STD_BYTE
 
-
 template <typename T>
-// NOTE: need suppression since c++14 does not allow "return {t}"
-// GSL_SUPPRESS(type.4) // NO-FORMAT: attribute // TODO: suppression does not work
 constexpr gsl::impl::byte to_byte(T t) noexcept
 {
-    static_assert(std::is_same<T, unsigned char>::value,
-                  "gsl::to_byte(t) must be provided an unsigned char, otherwise data loss may occur. "
-                  "If you are calling to_byte with an integer constant use: gsl::to_byte<t>() version.");
+    static_assert(
+        std::is_same<T, unsigned char>::value,
+        "gsl::to_byte(t) must be provided an unsigned char, otherwise data loss may occur. "
+        "If you are calling to_byte with an integer constant use: gsl::to_byte<t>() version.");
     return gsl::impl::byte(t);
 }
 

include/gsl/gsl

@@ -18,13 +18,13 @@
 #define GSL_GSL_H
 
 // IWYU pragma: begin_exports
-#include "./algorithm"   // copy
-#include "./assert"      // Ensures/Expects
-#include "./byte"        // byte
-#include "./pointers"    // owner, not_null
-#include "./span"        // span
-#include "./zstring"     // zstring
-#include "./util"        // finally()/narrow_cast()...
+#include "./algorithm" // copy
+#include "./assert"    // Ensures/Expects
+#include "./byte"      // byte
+#include "./pointers"  // owner, not_null
+#include "./span"      // span
+#include "./util"      // finally()/narrow_cast()...
+#include "./zstring"   // zstring
 
 #ifdef __cpp_exceptions
 #include "./narrow" // narrow()

include/gsl/narrow

@@ -16,8 +16,8 @@
 
 #ifndef GSL_NARROW_H
 #define GSL_NARROW_H
-#include "./assert"    // for GSL_SUPPRESS
-#include "./util"      // for narrow_cast
+#include "./assert"  // for GSL_SUPPRESS
+#include "./util"    // for narrow_cast
 #include <exception> // for std::exception
 namespace gsl
 {
@@ -28,53 +28,48 @@ struct narrowing_error : public std::exception
 
 // narrow() : a checked version of narrow_cast() that throws if the cast changed the value
 template <class T, class U, typename std::enable_if<std::is_arithmetic<T>::value>::type* = nullptr>
-// clang-format off
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-GSL_SUPPRESS(es.46) // NO-FORMAT: attribute // The warning suggests that a floating->unsigned conversion can occur
-                                            // in the static_cast below, and that gsl::narrow should be used instead.
-                                            // Suppress this warning, since gsl::narrow is defined in terms of
-                                            // static_cast
-    // clang-format on
+GSL_SUPPRESS(type.1)
+GSL_SUPPRESS(es.46) // The warning suggests that a floating->unsigned conversion can occur
+                    // in the static_cast below, and that gsl::narrow should be used instead.
+                    // Suppress this warning, since gsl::narrow is defined in terms of
+                    // static_cast
     constexpr T narrow(U u)
 {
     constexpr const bool is_different_signedness =
         (std::is_signed<T>::value != std::is_signed<U>::value);
 
-GSL_SUPPRESS(es.103) // NO-FORMAT: attribute // don't overflow
-GSL_SUPPRESS(es.104) // NO-FORMAT: attribute // don't underflow
-GSL_SUPPRESS(p.2) // NO-FORMAT: attribute // don't rely on undefined behavior
-    const T t = narrow_cast<T>(u); // While this is technically undefined behavior in some cases (i.e., if the source value is of floating-point type
-                                   // and cannot fit into the destination integral type), the resultant behavior is benign on the platforms
-                                   // that we target (i.e., no hardware trap representations are hit).
+    GSL_SUPPRESS(es.103) // don't overflow
+    GSL_SUPPRESS(es.104) // don't underflow
+    GSL_SUPPRESS(p.2)    // don't rely on undefined behavior
+    const T t = narrow_cast<T>(
+        u); // While this is technically undefined behavior in some cases (i.e., if the source value
+            // is of floating-point type and cannot fit into the destination integral type), the
+            // resultant behavior is benign on the platforms that we target (i.e., no hardware trap
+            // representations are hit).
 
 #if defined(__clang__) || defined(__GNUC__)
-    #pragma GCC diagnostic push
-    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-equal"
 #endif
     // Note: NaN will always throw, since NaN != NaN
     if (static_cast<U>(t) != u || (is_different_signedness && ((t < T{}) != (u < U{}))))
     {
         throw narrowing_error{};
     }
 #if defined(__clang__) || defined(__GNUC__)
-    #pragma GCC diagnostic pop
+#pragma GCC diagnostic pop
 #endif
 
     return t;
 }
 
 template <class T, class U, typename std::enable_if<!std::is_arithmetic<T>::value>::type* = nullptr>
-// clang-format off
-GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
-    // clang-format on
-    constexpr T narrow(U u)
+GSL_SUPPRESS(type.1)
+constexpr T narrow(U u)
 {
     const T t = narrow_cast<T>(u);
 
-    if (static_cast<U>(t) != u)
-    {
-        throw narrowing_error{};
-    }
+    if (static_cast<U>(t) != u) { throw narrowing_error{}; }
 
     return t;
 }