FindBZip2: Add BZip2_VERSION

This deprecates the BZIP2_VERSION result variable.

Issue: #27088

Help/release/dev/find-modules.rst

@@ -0,0 +1,5 @@
+Find Modules
+------------
+
+* The :module:`FindBZip2` module now provides a ``BZip2_VERSION`` result
+  variable.  The ``BZIP2_VERSION`` result variable is deprecated.

Modules/FindBZip2.cmake

@@ -28,8 +28,14 @@ Result Variables
 This module defines the following variables:
 
 ``BZip2_FOUND``
-  Boolean indicating whether the BZip2 library is found.  For backward
-  compatibility, the ``BZIP2_FOUND`` variable is also set to the same value.
+  Boolean indicating whether (the requested version of) BZip2 library is
+  found.  For backward compatibility, the ``BZIP2_FOUND`` variable is also
+  set to the same value.
+
+``BZip2_VERSION``
+  .. versionadded:: 4.2
+
+  The version of BZip2 found.
 
 ``BZIP2_INCLUDE_DIRS``
   .. versionadded:: 3.12
@@ -39,11 +45,6 @@ This module defines the following variables:
 ``BZIP2_LIBRARIES``
   Libraries needed for linking to use BZip2.
 
-``BZIP2_VERSION``
-  .. versionadded:: 3.26
-
-  The version of BZip2 found.
-
 Cache Variables
 ^^^^^^^^^^^^^^^
 
@@ -63,14 +64,22 @@ The following cache variables may also be set:
   (e.g., ``BZ2_bzCompressInit()``).  Versions of BZip2 prior to 1.0.0 used
   unprefixed function names (e.g., ``bzCompressInit()``).
 
-Legacy Variables
-^^^^^^^^^^^^^^^^
+Deprecated Variables
+^^^^^^^^^^^^^^^^^^^^
 
 The following variables are provided for backward compatibility:
 
 ``BZIP2_VERSION_STRING``
-  .. versionchanged:: 3.26
-    Superseded by ``BZIP2_VERSION``.
+  .. deprecated:: 3.26
+    Superseded by the ``BZIP2_VERSION`` (and ``BZip2_VERSION``).
+
+  The version of BZip2 found.
+
+``BZIP2_VERSION``
+  .. versionadded:: 3.26
+
+  .. deprecated:: 4.2
+    Superseded by the ``BZip2_VERSION``.
 
   The version of BZip2 found.
 
@@ -108,12 +117,13 @@ if (BZIP2_INCLUDE_DIR AND EXISTS "${BZIP2_INCLUDE_DIR}/bzlib.h")
     file(STRINGS "${BZIP2_INCLUDE_DIR}/bzlib.h" BZLIB_H REGEX "bzip2/libbzip2 version [0-9]+\\.[^ ]+ of [0-9]+ ")
     string(REGEX REPLACE ".* bzip2/libbzip2 version ([0-9]+\\.[^ ]+) of [0-9]+ .*" "\\1" BZIP2_VERSION_STRING "${BZLIB_H}")
     set(BZIP2_VERSION ${BZIP2_VERSION_STRING})
+    set(BZip2_VERSION ${BZIP2_VERSION_STRING})
 endif ()
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(BZip2
                                   REQUIRED_VARS BZIP2_LIBRARIES BZIP2_INCLUDE_DIR
-                                  VERSION_VAR BZIP2_VERSION)
+                                  VERSION_VAR BZip2_VERSION)
 
 if (BZip2_FOUND)
   set(BZIP2_INCLUDE_DIRS ${BZIP2_INCLUDE_DIR})
@@ -126,7 +136,7 @@ if (BZip2_FOUND)
 
   # Versions before 1.0.2 required <stdio.h> for the FILE definition.
   set(BZip2_headers "bzlib.h")
-  if(BZIP2_VERSION VERSION_LESS "1.0.2")
+  if(BZip2_VERSION VERSION_LESS "1.0.2")
     list(PREPEND BZip2_headers "stdio.h")
   endif()
   check_symbol_exists(BZ2_bzCompressInit "${BZip2_headers}" BZIP2_NEED_PREFIX)

Tests/CMakeOnly/AllFindModules/CMakeLists.txt

@@ -90,15 +90,42 @@ endmacro()
 # If any of these modules reported that it was found a version number should have been
 # reported.
 
-foreach(VTEST ALSA ARMADILLO BZIP2 CUPS CURL EXPAT FREETYPE GETTEXT GIT HG
-        HSPELL ICOTOOL JASPER LIBLZMA LIBXML2 LIBXSLT LTTNGUST PERL PKG_CONFIG
-        PostgreSQL TIFF ZLIB)
-    check_version_string(${VTEST} ${VTEST}_VERSION_STRING)
+foreach(
+  VTEST
+    ALSA ARMADILLO
+    BZIP2
+    CUPS CURL
+    EXPAT
+    FREETYPE
+    GETTEXT GIT
+    HG HSPELL
+    ICOTOOL
+    JASPER
+    LIBLZMA LIBXML2 LIBXSLT LTTNGUST
+    PERL PKG_CONFIG PostgreSQL
+    TIFF
+    ZLIB
+)
+  check_version_string(${VTEST} ${VTEST}_VERSION_STRING)
 endforeach()
 
-foreach(VTEST BISON Boost BZIP2 CUDA DOXYGEN FLEX GIF GTK2
-    HDF5 JPEG LibArchive LIBLZMA OPENSCENEGRAPH Ruby RUBY SWIG Protobuf ZLIB)
-    check_version_string(${VTEST} ${VTEST}_VERSION)
+foreach(
+  VTEST
+    BISON Boost BZip2 BZIP2
+    CUDA
+    DOXYGEN
+    FLEX
+    GIF GTK2
+    HDF5
+    JPEG
+    LibArchive LIBLZMA
+    OPENSCENEGRAPH
+    Protobuf
+    Ruby RUBY
+    SWIG
+    ZLIB
+)
+  check_version_string(${VTEST} ${VTEST}_VERSION)
 endforeach()
 
 check_version_string(PYTHONINTERP PYTHON_VERSION_STRING)

Tests/FindBZip2/Test/CMakeLists.txt

@@ -4,7 +4,7 @@ include(CTest)
 
 find_package(BZip2 REQUIRED)
 
-add_definitions(-DCMAKE_EXPECTED_BZip2_VERSION="${BZip2_VERSION_STRING}")
+add_definitions(-DCMAKE_EXPECTED_BZip2_VERSION="${BZip2_VERSION}")
 
 add_executable(test_tgt main.c)
 target_link_libraries(test_tgt BZip2::BZip2)

Tests/FindBZip2/Test/main.c

@@ -1,6 +1,7 @@
 #include <bzlib.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 int main(void)
 {
@@ -19,5 +20,9 @@ int main(void)
 
   remove("test.bzip2");
 
-  return 0;
+  printf("Found BZip2 version %s, expected version %s\n", BZ2_bzlibVersion(),
+         CMAKE_EXPECTED_BZip2_VERSION);
+
+  return strncmp(BZ2_bzlibVersion(), CMAKE_EXPECTED_BZip2_VERSION,
+                 strlen(CMAKE_EXPECTED_BZip2_VERSION));
 }