Skip redundant DLL copy on Windows

Since the library is now named 'scylladb', Cargo's output
(scylladb.dll, scylladb.lib) already matches the desired install
name. Use the Cargo output directly on Windows instead of copying
to an identical filename.

This also eliminates the class of problems where the import
library (.lib) internally references the original Cargo output
name, causing 'dll not found' errors if the file were renamed
(as was the case with the old scylla_cpp_driver -> scylla-cpp-driver
rename).

Author: wprzytula

scylla-rust-wrapper/CMakeLists.txt

@@ -64,18 +64,26 @@ else()
 endif()
 if(CASS_BUILD_SHARED)
   cargo_build(NAME scylladb CRATE_TYPE cdylib)
-  create_copy($<TARGET_FILE:scylladb_cdylib> ${INSTALL_NAME_SHARED})
-  add_library(scylladb SHARED IMPORTED GLOBAL)
-  add_dependencies(scylladb ${INSTALL_NAME_SHARED}_copy)
-  set_target_properties(scylladb PROPERTIES IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/${INSTALL_NAME_SHARED})
   if(WIN32)
+    # On Windows, Cargo's output name (scylladb.dll/.lib) already matches
+    # the desired install name, so no copy/rename is needed. We use the
+    # Cargo output paths directly. This avoids the problem where the import
+    # library internally references the original Cargo output name, causing
+    # "dll not found" errors if the file is renamed (#452).
+    add_library(scylladb SHARED IMPORTED GLOBAL)
+    add_dependencies(scylladb scylladb_cdylib_target)
+    set_target_properties(scylladb PROPERTIES IMPORTED_LOCATION $<TARGET_FILE:scylladb_cdylib>)
     get_target_property(SCYLLADB_IMPLIB scylladb_cdylib IMPORTED_IMPLIB)
     if(SCYLLADB_IMPLIB)
-      create_copy(${SCYLLADB_IMPLIB} ${INSTALL_NAME_SHARED_IMPLIB})
-      set_target_properties(scylladb PROPERTIES IMPORTED_IMPLIB ${CMAKE_BINARY_DIR}/${INSTALL_NAME_SHARED_IMPLIB})
+      set_target_properties(scylladb PROPERTIES IMPORTED_IMPLIB ${SCYLLADB_IMPLIB})
     endif()
-  endif()
-  if(NOT WIN32)
+  else()
+    # On Unix, we need to copy to add the version suffix
+    # (e.g. libscylladb.so -> libscylladb.so.X.Y.Z).
+    create_copy($<TARGET_FILE:scylladb_cdylib> ${INSTALL_NAME_SHARED})
+    add_library(scylladb SHARED IMPORTED GLOBAL)
+    add_dependencies(scylladb ${INSTALL_NAME_SHARED}_copy)
+    set_target_properties(scylladb PROPERTIES IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/${INSTALL_NAME_SHARED})
     create_symlink(${INSTALL_NAME_SHARED} ${INSTALL_NAME_SHARED_SYMLINK_VERSION})
     create_symlink(${INSTALL_NAME_SHARED} ${INSTALL_NAME_SHARED_SYMLINK_NO_VERSION})
     if(CASS_INSTALL_CASSANDRA_COMPAT)
@@ -158,12 +166,13 @@ endif()
 if(CASS_BUILD_SHARED)
   # Versioned shared library goes to runtime package
   if(WIN32)
-    install(FILES ${CMAKE_BINARY_DIR}/${INSTALL_NAME_SHARED}
+    install(FILES $<TARGET_FILE:scylladb>
       DESTINATION ${INSTALL_DLL_EXE_DIR}
       COMPONENT ${SCYLLA_DRIVER_RUNTIME_COMPONENT_NAME}
       PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ GROUP_EXECUTE GROUP_READ WORLD_EXECUTE WORLD_READ)
-    if(INSTALL_NAME_SHARED_IMPLIB)
-      install(FILES ${CMAKE_BINARY_DIR}/${INSTALL_NAME_SHARED_IMPLIB}
+    get_target_property(_scylladb_implib scylladb IMPORTED_IMPLIB)
+    if(_scylladb_implib)
+      install(FILES ${_scylladb_implib}
         DESTINATION ${CMAKE_INSTALL_LIBDIR}
         COMPONENT ${SCYLLA_DRIVER_DEV_COMPONENT_NAME})
     endif()