Use only one find_package call for zlib.

CMakeFilters.cmake

@@ -85,30 +85,33 @@ endif ()
 if(NOT DEFINED ZLIBNG_PACKAGE_NAME)
   set(ZLIBNG_PACKAGE_NAME "zlib-ng")
 endif ()
-option (HDF5_ENABLE_ZLIB_SUPPORT "Enable Zlib Filters" OFF)
 if (HDF5_ENABLE_ZLIB_SUPPORT)
   if (NOT H5_ZLIB_HEADER)
     if (NOT ZLIB_USE_EXTERNAL)
+      option (HDF5_DEFAULT_ZLIB_SYSTEM "Use the default system installed ZLIB" ON)
       if (HDF5_USE_ZLIB_NG)
         set (PACKAGE_NAME ${ZLIBNG_PACKAGE_NAME}${HDF_PACKAGE_EXT})
       else ()
         set (PACKAGE_NAME ${ZLIB_PACKAGE_NAME}${HDF_PACKAGE_EXT})
       endif ()
       set(ZLIB_FOUND FALSE)
-      if (HDF5_USE_ZLIB_STATIC)
-        set(ZLIB_SEARCH_TYPE static)
+      message (VERBOSE "Filter HDF5_ZLIB package name:${PACKAGE_NAME}")
+      if (HDF5_DEFAULT_ZLIB_SYSTEM)
+        # Expect that the default shared library is expected with FindZLIB.cmake
+        find_package (ZLIB MODULE)
       else ()
-        set(ZLIB_SEARCH_TYPE shared)
-      endif ()
-      # Search pure Config mode first
-      find_package (ZLIB NAMES ${PACKAGE_NAME} OPTIONAL_COMPONENTS ${ZLIB_SEARCH_TYPE})
-      if (NOT ZLIB_FOUND)
-        if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
-          set(ZLIB_USE_STATIC_LIBS  ${HDF5_USE_ZLIB_STATIC})
-        endif()
-        find_package (ZLIB) # Legacy find
+        # Expect that a correctly built library with CMake config files is available
+        if (HDF5_USE_ZLIB_STATIC)
+          set(ZLIB_SEARCH_TYPE static)
+          if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
+            set(ZLIB_USE_STATIC_LIBS  ${HDF5_USE_ZLIB_STATIC})
+          endif()
+        else ()
+          set(ZLIB_SEARCH_TYPE shared)
+        endif ()
+        find_package (ZLIB NAMES ${PACKAGE_NAME} CONFIG OPTIONAL_COMPONENTS ${ZLIB_SEARCH_TYPE})
       endif ()
-      set(H5_ZLIB_FOUND ${ZLIB_FOUND})
+      set(H5_ZLIB_FOUND ZLIB_FOUND})
       if (H5_ZLIB_FOUND)
         if (HDF5_USE_ZLIB_NG)
           set (H5_ZLIB_HEADER "zlib-ng.h")
@@ -117,11 +120,13 @@ if (HDF5_ENABLE_ZLIB_SUPPORT)
         endif ()
         set (H5_ZLIB_INCLUDE_DIR_GEN ${ZLIB_INCLUDE_DIR})
         set (H5_ZLIB_INCLUDE_DIRS ${H5_ZLIB_INCLUDE_DIRS} ${ZLIB_INCLUDE_DIR})
-        # The FindZLIB.cmake module does not set an OUTPUT_NAME
-        # on the target. The target returned is: ZLIB::ZLIB
-        get_filename_component (libname ${ZLIB_LIBRARIES} NAME_WLE)
-        string (REGEX REPLACE "^lib" "" libname ${libname})
-        set_target_properties (ZLIB::ZLIB PROPERTIES OUTPUT_NAME ${libname})
+        if (NOT WIN32) #windows has a list of names
+          # The FindZLIB.cmake module does not set an OUTPUT_NAME
+          # on the target. The target returned is: ZLIB::ZLIB
+          get_filename_component (libname ${ZLIB_LIBRARIES} NAME_WLE)
+          string (REGEX REPLACE "^lib" "" libname ${libname})
+          set_target_properties (ZLIB::ZLIB PROPERTIES OUTPUT_NAME ${libname})
+        endif ()
         set (LINK_COMP_LIBS ${LINK_COMP_LIBS} ZLIB::ZLIB)
       endif ()
     else ()
@@ -161,7 +166,6 @@ set(H5_SZIP_FOUND FALSE)
 if(NOT DEFINED LIBAEC_PACKAGE_NAME)
   set(LIBAEC_PACKAGE_NAME "libaec")
 endif ()
-option (HDF5_ENABLE_SZIP_SUPPORT "Use SZip Filter" OFF)
 if (HDF5_ENABLE_SZIP_SUPPORT)
   option (HDF5_ENABLE_SZIP_ENCODING "Use SZip Encoding" ON)
   if (NOT SZIP_USE_EXTERNAL)

CMakeLists.txt

@@ -6,6 +6,11 @@ if (POLICY CMP0074)
   cmake_policy (SET CMP0074 NEW)
 endif ()
 
+if (POLICY CMP0144)
+  # <PACKAGENAME> is the upper-cased package name.
+  cmake_policy (SET CMP0144 NEW)
+endif ()
+
 if (POLICY CMP0083)
   # To control generation of Position Independent Executable (PIE) or not,
   # some flags are required at link time.

release_docs/INSTALL_CMake.txt

@@ -877,6 +877,7 @@ if (BUILD_TESTING)
 HDF5_ALLOW_EXTERNAL_SUPPORT "Allow External Library Building (NO GIT TGZ)"       "NO"
 HDF5_ENABLE_PLUGIN_SUPPORT  "Enable PLUGIN Filters"                              OFF
 HDF5_ENABLE_SZIP_SUPPORT    "Use SZip Filter"                                    OFF
+HDF5_DEFAULT_ZLIB_SYSTEM    "Use the default system installed ZLIB"              ON
 HDF5_ENABLE_ZLIB_SUPPORT    "Enable Zlib Filters"                                OFF
 
 if (HDF5_USE_ZLIB_NG)

release_docs/RELEASE.txt

@@ -565,6 +565,13 @@ Bug Fixes since HDF5-2.0.0 release
 
     Configuration
     -------------
+    - When using a system installed zlib library, the shared library is expected to
+      be found in the system library path.
+
+      Setting the HDF5_DEFAULT_ZLIB_SYSTEM option to OFF, the system installed zlib,
+      or an alternate installed zlib library, is expected to have a correct
+      zlib-config.cmake file.
+
     - Use pre-installed libaec compression library
 
       The CMake logic for finding the libaec compression library has been