From f6969f1a7e97d7ba3790456c0dba032c5728c5e8 Mon Sep 17 00:00:00 2001
From: Sean McBride <sean@rogue-research.com>
Date: Thu, 19 Jun 2025 15:39:31 -0400
Subject: [PATCH] COMP: suppress Clang -Wduplicate-enum

Also use __has_warning to guard againist trying to disable warnings that are unknown (ex: in older Clangs).
---
 .clang-format                                |  1 +
 Examples/.clang-format                       |  1 +
 Modules/Core/Common/include/itkCommonEnums.h |  3 +++
 Modules/Core/Common/include/itkMacro.h       | 14 ++++++++++++--
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/.clang-format b/.clang-format
index 7252d3eee3f..2fd9142befd 100644
--- a/.clang-format
+++ b/.clang-format
@@ -297,6 +297,7 @@ StatementMacros:
   - ITK_CLANG_PRAGMA_PUSH
   - ITK_CLANG_PRAGMA_POP
   - ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant
+  - ITK_CLANG_SUPPRESS_Wduplicate_enum
   - CLANG_PRAGMA_PUSH
   - CLANG_PRAGMA_POP
   - CLANG_SUPPRESS_Wfloat_equal
diff --git a/Examples/.clang-format b/Examples/.clang-format
index aee28847baa..37bd3afa8a1 100644
--- a/Examples/.clang-format
+++ b/Examples/.clang-format
@@ -297,6 +297,7 @@ StatementMacros:
   - ITK_CLANG_PRAGMA_PUSH
   - ITK_CLANG_PRAGMA_POP
   - ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant
+  - ITK_CLANG_SUPPRESS_Wduplicate_enum
   - CLANG_PRAGMA_PUSH
   - CLANG_PRAGMA_POP
   - CLANG_SUPPRESS_Wfloat_equal
diff --git a/Modules/Core/Common/include/itkCommonEnums.h b/Modules/Core/Common/include/itkCommonEnums.h
index d6d2422f059..127275afd9c 100644
--- a/Modules/Core/Common/include/itkCommonEnums.h
+++ b/Modules/Core/Common/include/itkCommonEnums.h
@@ -72,6 +72,8 @@ class CommonEnums
    * refers to the actual storage class associated with either a
    * SCALAR pixel type or elements of a compound pixel.
    */
+  ITK_CLANG_PRAGMA_PUSH
+  ITK_CLANG_SUPPRESS_Wduplicate_enum
   enum class IOComponent : uint8_t
   {
     UNKNOWNCOMPONENTTYPE,
@@ -99,6 +101,7 @@ class CommonEnums
     FLOAT32 = FLOAT,
     FLOAT64 = DOUBLE
   };
+  ITK_CLANG_PRAGMA_POP
 
   /**
    * \ingroup ITKCommon
diff --git a/Modules/Core/Common/include/itkMacro.h b/Modules/Core/Common/include/itkMacro.h
index 433600a40a0..f2fe5f5314e 100644
--- a/Modules/Core/Common/include/itkMacro.h
+++ b/Modules/Core/Common/include/itkMacro.h
@@ -121,12 +121,22 @@ namespace itk
 #if defined(__clang__) && defined(__has_warning)
 #  define ITK_CLANG_PRAGMA_PUSH ITK_PRAGMA(clang diagnostic push)
 #  define ITK_CLANG_PRAGMA_POP ITK_PRAGMA(clang diagnostic pop)
-#  define ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant \
-    ITK_PRAGMA(clang diagnostic ignored "-Wzero-as-null-pointer-constant")
+#  if __has_warning("-Wzero-as-null-pointer-constant")
+#    define ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant \
+      ITK_PRAGMA(clang diagnostic ignored "-Wzero-as-null-pointer-constant")
+#  else
+#    define ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant
+#  endif
+#  if __has_warning("-Wduplicate-enum")
+#    define ITK_CLANG_SUPPRESS_Wduplicate_enum ITK_PRAGMA(clang diagnostic ignored "-Wduplicate-enum")
+#  else
+#    define ITK_CLANG_SUPPRESS_Wduplicate_enum
+#  endif
 #else
 #  define ITK_CLANG_PRAGMA_PUSH
 #  define ITK_CLANG_PRAGMA_POP
 #  define ITK_CLANG_SUPPRESS_Wzero_as_null_pointer_constant
+#  define ITK_CLANG_SUPPRESS_Wduplicate_enum
 #endif
 
 // These were not intended as public API, but some code was nevertheless using them.