From f3d530f73559c77750ebe5648ac6ecac7b5b87a7 Mon Sep 17 00:00:00 2001
From: Murray Stevenson <50844517+murraystevenson@users.noreply.github.com>
Date: Fri, 14 Aug 2026 15:28:20 -0700
Subject: [PATCH 1/2] IECore, IECoreScene, IECoreAlembic : Add `fmt` 12.2.0
 compatibility

---
 Changes                                                  | 7 +++++++
 contrib/IECoreAlembic/src/IECoreAlembic/AlembicScene.cpp | 2 +-
 include/IECore/TypeIds.h                                 | 6 ++++++
 include/IECoreScene/PrimitiveVariable.h                  | 6 ++++++
 src/IECore/StreamIndexedIO.cpp                           | 6 ++++++
 5 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/Changes b/Changes
index 69d171b63a..6fafc938e4 100644
--- a/Changes
+++ b/Changes
@@ -5,6 +5,13 @@ Improvements
 ------------
 
 - PathMatcher : Added `in()` and `containing()` methods.
+- TypeId : Added `format_as` overload, so that TypeIds can be passed to `fmt::format()`.
+- PrimitiveVariable : Added `format_as` overload for `Interpolation`, so that it can be passed to `fmt::format()`.
+
+Build
+-----
+
+- LibFormat : Added compatibility with `fmt` 12.2.0.
 
 10.7.0.0
 ========
diff --git a/contrib/IECoreAlembic/src/IECoreAlembic/AlembicScene.cpp b/contrib/IECoreAlembic/src/IECoreAlembic/AlembicScene.cpp
index 9da070f488..0f5428487a 100644
--- a/contrib/IECoreAlembic/src/IECoreAlembic/AlembicScene.cpp
+++ b/contrib/IECoreAlembic/src/IECoreAlembic/AlembicScene.cpp
@@ -836,7 +836,7 @@ class AlembicScene::AlembicReader : public AlembicIO
 			IECore::msg(
 				IECore::Msg::Warning,
 				"AlembicScene::readAttributeAtSample",
-				"Unsupported attribute type datatype: \"{}\" extent:{} interpretation:\"{}\"", pod, extent, getInterpretation()
+				"Unsupported attribute type datatype: \"{}\" extent:{} interpretation:\"{}\"", fmt::underlying( pod ), extent, getInterpretation()
 			);
 
 			return nullptr;
diff --git a/include/IECore/TypeIds.h b/include/IECore/TypeIds.h
index 9a02b4108c..23112ff267 100644
--- a/include/IECore/TypeIds.h
+++ b/include/IECore/TypeIds.h
@@ -326,6 +326,12 @@ enum TypeId
 
 };
 
+/// Enable fmtlib formatting of TypeId as its numeric value.
+inline int format_as( TypeId typeId )
+{
+	return static_cast<int>( typeId );
+}
+
 } // namespace IECore
 
 #endif // IE_CORE_TYPEIDS_H
diff --git a/include/IECoreScene/PrimitiveVariable.h b/include/IECoreScene/PrimitiveVariable.h
index a5a403c4c7..401f8964e3 100644
--- a/include/IECoreScene/PrimitiveVariable.h
+++ b/include/IECoreScene/PrimitiveVariable.h
@@ -108,6 +108,12 @@ struct IECORESCENE_API PrimitiveVariable
 
 };
 
+/// Enable fmtlib formatting of Interpolation as its numeric value.
+inline int format_as( PrimitiveVariable::Interpolation interpolation )
+{
+	return static_cast<int>( interpolation );
+}
+
 /// Utility class for iterating the `data` field from
 /// a PrimitiveVariable, using the `indices` field
 /// appropriately if it exists.
diff --git a/src/IECore/StreamIndexedIO.cpp b/src/IECore/StreamIndexedIO.cpp
index 0d9feb44e6..d6196d408c 100644
--- a/src/IECore/StreamIndexedIO.cpp
+++ b/src/IECore/StreamIndexedIO.cpp
@@ -579,6 +579,12 @@ protected :
 
 };
 
+/// Enable fmtlib formatting of NodeType as its numeric value.
+inline int format_as( NodeBase::NodeType nodeType )
+{
+	return static_cast<int>( nodeType );
+}
+
 /// Class that represents small data nodes
 class SmallDataNode : public NodeBase
 {

From 6ae5b13ac2d479617d63739e5feee7ade29d4e95 Mon Sep 17 00:00:00 2001
From: Murray Stevenson <50844517+murraystevenson@users.noreply.github.com>
Date: Fri, 14 Aug 2026 15:36:22 -0700
Subject: [PATCH 2/2] SConstruct : Remove FMT_DEPRECATED workaround

With the addition of the `format_as` overloads in the previous commit, we no longer hit deprecated code in `fmt` and can remove this workaround.
---
 SConstruct | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/SConstruct b/SConstruct
index 34dcdae00a..176906c449 100644
--- a/SConstruct
+++ b/SConstruct
@@ -873,10 +873,6 @@ if env["PLATFORM"] != "win32" :
 		if clangVersion >= [ 15, 0, 0 ] :
 			env.Append( CXXFLAGS = [ "-DBOOST_NO_CXX98_FUNCTION_BASE", "-D_HAS_AUTO_PTR_ETC=0" ] )
 		if clangVersion >= [ 16, 0, 0 ] :
-			# XCode 16 warns about deprecations in fmtlib. Overriding `FMT_DEPRECATED`
-			# allows us to remove the [[deprecated]] attributes and still build with
-			# `-Werror,-Wdeprecated-declarations`.
-			env.Append( CPPDEFINES = [ ( "FMT_DEPRECATED", "" ), ] )
 			# Disable new warnings about ObjectInterpolator::InterpolatorDescription's reinterpret_cast.
 			env.Append( CXXFLAGS = [ "-Wno-cast-function-type-mismatch" ] )
 		# Disable FMA on arm64 builds to limit floating point discrepancies with x86_64 builds.