Merge pull request #5698 from johnhaddon/delightEnvFix

IECoreDelight : Fix KeyError when `DELIGHT` not defined

Changes.md

@@ -1,6 +1,11 @@
 1.4.x.x (relative to 1.4.0.0b1)
 =======
 
+Fixes
+-----
+
+- 3Delight : Fixed startup errors on Windows when the `DELIGHT` environment variable wasn't defined [^1].
+
 Breaking Changes
 ----------------
 
@@ -9,6 +14,8 @@ Breaking Changes
   - Removed all texture cache options. These had never been exposed in the UI because this never became an offical Cycles feature.
   - Removed `cryptomatteAccurate`. This feature is no longer present in Cycles.
 
+[^1] : To be omitted from final release notes for 1.4.0.0.
+
 1.4.0.0b1 (relative to 1.3.x.x)
 =========
 

python/IECoreDelight/__init__.py

@@ -37,7 +37,7 @@
 import os
 import pathlib
 
-if hasattr( os, "add_dll_directory" ) :
+if hasattr( os, "add_dll_directory" ) and "DELIGHT" in os.environ :
 	os.add_dll_directory( ( pathlib.Path( os.environ["DELIGHT"] ) / "bin" ).resolve() )
 del os, pathlib # Don't pollute the namespace
 
@@ -56,4 +56,4 @@
 	try :
 		ctypes.CDLL( "IECoreDelight.dll" )
 	except :
-		raise ImportError
+		raise ImportError