Remove version-check for relnum in H5check. (#812)

* Remove version-check for relnum in H5check.

* Add in release exception code check

* Fix typos

* Fix more typos

* Rework comments

* format change

* format whitespace

* Library version must be less than or equal to headers

* Need the NOT version of the compare

* Enable release+1 check for PASS

* Add release note

* Update note

5 files changed, 227 insertions, 147 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index bd186d8..314a713 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -463,6 +463,25 @@ New Features
 
     Library:
     --------
+    - Change how the release part of version, in major.minor.release is checked
+      for compatibility
+
+      The HDF5 library uses a function, H5check_version, to check that
+      the version defined in the header files, which is used to compile an
+      application is compatible with the version codified in the library, which
+      the application loads at runtime. This previously required an exact match
+      or the library would print a warning, dump the build settings and then
+      abort or continue. An environment variable controlled the logic.
+
+      Now the function first checks that the library release version, in
+      major.minor.release, is not older than the version in the headers.
+      Secondly, if the release version is different, it checks if either
+      the library version or the header version is in the exception list, in
+      which case the release part of version, in major.minor.release, must
+      be exact. An environment variable still controls the logic.
+
+        (ADB - 2021/07/27)
+
     - gcc warning suppression macros were moved out of H5public.h
 
       The HDF5 library uses a set of macros to suppress warnings on gcc.
diff --git a/src/H5.c b/src/H5.c
index 71a8a30..12d226c 100644
--- a/src/H5.c
+++ b/src/H5.c
@@ -70,6 +70,10 @@ hbool_t H5_PKG_INIT_VAR = FALSE;
 /* Library Private Variables */
 /*****************************/
 
+/* Library incompatible release versions */
+const unsigned VERS_RELEASE_EXCEPTIONS[]    = {0};
+const unsigned VERS_RELEASE_EXCEPTIONS_SIZE = 0;
+
 /* statically initialize block for pthread_once call used in initializing */
 /* the first global mutex                                                 */
 #ifdef H5_HAVE_THREADSAFE
@@ -281,13 +285,13 @@ done:
 } /* end H5_init_library() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5_term_library
+ * Function:    H5_term_library
  *
- * Purpose:	Terminate interfaces in a well-defined order due to
- *		dependencies among the interfaces, then terminate
- *		library-specific data.
+ * Purpose:    Terminate interfaces in a well-defined order due to
+ *        dependencies among the interfaces, then terminate
+ *        library-specific data.
  *
- * Return:	void
+ * Return:    void
  *
  *-------------------------------------------------------------------------
  */
@@ -505,22 +509,22 @@ done:
 } /* end H5_term_library() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5dont_atexit
+ * Function:    H5dont_atexit
  *
- * Purpose:	Indicates that the library is not to clean up after itself
- *		when the application exits by calling exit() or returning
- *		from main().  This function must be called before any other
- *		HDF5 function or constant is used or it will have no effect.
+ * Purpose:    Indicates that the library is not to clean up after itself
+ *        when the application exits by calling exit() or returning
+ *        from main().  This function must be called before any other
+ *        HDF5 function or constant is used or it will have no effect.
  *
- *		If this function is used then certain memory buffers will not
- *		be de-allocated nor will open files be flushed automatically.
- *		The application may still call H5close() explicitly to
- *		accomplish these things.
+ *        If this function is used then certain memory buffers will not
+ *        be de-allocated nor will open files be flushed automatically.
+ *        The application may still call H5close() explicitly to
+ *        accomplish these things.
  *
- * Return:	Success:	non-negative
+ * Return:    Success:    non-negative
  *
- *		Failure:	negative if this function is called more than
- *				once or if it is called too late.
+ *        Failure:    negative if this function is called more than
+ *                once or if it is called too late.
  *
  *-------------------------------------------------------------------------
  */
@@ -541,19 +545,19 @@ H5dont_atexit(void)
 } /* end H5dont_atexit() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5garbage_collect
+ * Function:    H5garbage_collect
  *
- * Purpose:	Walks through all the garbage collection routines for the
- *		library, which are supposed to free any unused memory they have
- *		allocated.
+ * Purpose:    Walks through all the garbage collection routines for the
+ *        library, which are supposed to free any unused memory they have
+ *        allocated.
  *
  *      These should probably be registered dynamically in a linked list of
  *          functions to call, but there aren't that many right now, so we
  *          hard-wire them...
  *
- * Return:	Success:	non-negative
+ * Return:    Success:    non-negative
  *
- *		Failure:	negative
+ *        Failure:    negative
  *
  *-------------------------------------------------------------------------
  */
@@ -574,9 +578,9 @@ done:
 } /* end H5garbage_collect() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5set_free_list_limits
+ * Function:    H5set_free_list_limits
  *
- * Purpose:	Sets limits on the different kinds of free lists.  Setting a value
+ * Purpose:    Sets limits on the different kinds of free lists.  Setting a value
  *      of -1 for a limit means no limit of that type.  These limits are global
  *      for the entire library.  Each "global" limit only applies to free lists
  *      of that type, so if an application sets a limit of 1 MB on each of the
@@ -594,9 +598,9 @@ done:
  *  int blk_global_lim;  IN: The limit on all "block" free list memory used
  *  int blk_list_lim;    IN: The limit on memory used in each "block" free list
  *
- * Return:	Success:	non-negative
+ * Return:    Success:    non-negative
  *
- *		Failure:	negative
+ *        Failure:    negative
  *
  *-------------------------------------------------------------------------
  */
@@ -620,11 +624,11 @@ done:
 } /* end H5set_free_list_limits() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5get_free_list_sizes
+ * Function:    H5get_free_list_sizes
  *
- * Purpose:	Gets the current size of the different kinds of free lists that
- *	the library uses to manage memory.  The free list sizes can be set with
- *	H5set_free_list_limits and garbage collected with H5garbage_collect.
+ * Purpose:    Gets the current size of the different kinds of free lists that
+ *    the library uses to manage memory.  The free list sizes can be set with
+ *    H5set_free_list_limits and garbage collected with H5garbage_collect.
  *      These lists are global for the entire library.
  *
  * Parameters:
@@ -633,8 +637,8 @@ done:
  *  size_t *blk_size;    OUT: The current size of all "block" free list memory used
  *  size_t *fac_size;    OUT: The current size of all "factory" free list memory used
  *
- * Return:	Success:	non-negative
- *		Failure:	negative
+ * Return:    Success:    non-negative
+ *        Failure:    negative
  *
  * Programmer:  Quincey Koziol
  *              Friday, March 6, 2020
@@ -659,23 +663,23 @@ done:
 } /* end H5get_free_list_sizes() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5get_alloc_stats
+ * Function:    H5get_alloc_stats
  *
- * Purpose:	Gets the memory allocation statistics for the library, if the
- *	--enable-memory-alloc-sanity-check option was given when building the
+ * Purpose:    Gets the memory allocation statistics for the library, if the
+ *    --enable-memory-alloc-sanity-check option was given when building the
  *      library.  Applications can check whether this option was enabled by
- *	detecting if the 'H5_MEMORY_ALLOC_SANITY_CHECK' macro is defined.  This
- *	option is enabled by default for debug builds of the library and
- *	disabled by default for non-debug builds.  If the option is not enabled,
- *	all the values returned with be 0.  These statistics are global for the
- *	entire library, but don't include allocations from chunked dataset I/O
- *	filters or non-native VOL connectors.
+ *    detecting if the 'H5_MEMORY_ALLOC_SANITY_CHECK' macro is defined.  This
+ *    option is enabled by default for debug builds of the library and
+ *    disabled by default for non-debug builds.  If the option is not enabled,
+ *    all the values returned with be 0.  These statistics are global for the
+ *    entire library, but don't include allocations from chunked dataset I/O
+ *    filters or non-native VOL connectors.
  *
  * Parameters:
  *  H5_alloc_stats_t *stats;            OUT: Memory allocation statistics
  *
- * Return:	Success:	non-negative
- *		Failure:	negative
+ * Return:    Success:    non-negative
+ *        Failure:    negative
  *
  * Programmer:  Quincey Koziol
  *              Saturday, March 7, 2020
@@ -808,12 +812,12 @@ H5__debug_mask(const char *s)
 #ifdef H5_HAVE_PARALLEL
 
 /*-------------------------------------------------------------------------
- * Function:	H5__mpi_delete_cb
+ * Function:    H5__mpi_delete_cb
  *
- * Purpose:	Callback attribute on MPI_COMM_SELF to terminate the HDF5
+ * Purpose:    Callback attribute on MPI_COMM_SELF to terminate the HDF5
  *              library when the communicator is destroyed, i.e. on MPI_Finalize.
  *
- * Return:	MPI_SUCCESS
+ * Return:    MPI_SUCCESS
  *
  *-------------------------------------------------------------------------
  */
@@ -827,18 +831,18 @@ H5__mpi_delete_cb(MPI_Comm H5_ATTR_UNUSED comm, int H5_ATTR_UNUSED keyval, void
 #endif /*H5_HAVE_PARALLEL*/
 
 /*-------------------------------------------------------------------------
- * Function:	H5get_libversion
+ * Function:    H5get_libversion
  *
- * Purpose:	Returns the library version numbers through arguments. MAJNUM
- *		will be the major revision number of the library, MINNUM the
- *		minor revision number, and RELNUM the release revision number.
+ * Purpose:    Returns the library version numbers through arguments. MAJNUM
+ *        will be the major revision number of the library, MINNUM the
+ *        minor revision number, and RELNUM the release revision number.
  *
- * Note:	When printing an HDF5 version number it should be printed as
+ * Note:    When printing an HDF5 version number it should be printed as
  *
- * 		printf("%u.%u.%u", maj, min, rel)		or
- *		printf("version %u.%u release %u", maj, min, rel)
+ *         printf("%u.%u.%u", maj, min, rel)        or
+ *        printf("version %u.%u release %u", maj, min, rel)
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:    Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
@@ -863,17 +867,20 @@ done:
 } /* end H5get_libversion() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5check_version
+ * Function:    H5check_version
  *
- * Purpose:	Verifies that the arguments match the version numbers
- *		compiled into the library.  This function is intended to be
- *		called from user to verify that the versions of header files
- *		compiled into the application match the version of the hdf5
- *		library.
+ * Purpose:    Verifies that the arguments match the version numbers
+ *        compiled into the library.  This function is intended to be
+ *        called from user to verify that the versions of header files
+ *        compiled into the application match the version of the hdf5
+ *        library.
+ *        Within major.minor.release version, the expectation
+ *        is that all release versions are compatible, exceptions to
+ *        this rule must be added to the VERS_RELEASE_EXCEPTIONS list.
  *
- * Return:	Success:	SUCCEED
+ * Return:    Success:    SUCCEED
  *
- *		Failure:	abort()
+ *        Failure:    abort()
  *
  *-------------------------------------------------------------------------
  */
@@ -886,6 +893,15 @@ done:
     "linked with a different version of static or shared HDF5 library.\n"                                    \
     "You should recompile the application or check your shared library related\n"                            \
     "settings such as 'LD_LIBRARY_PATH'.\n"
+#define RELEASE_MISMATCH_WARNING                                                                             \
+    "Warning! ***HDF5 library release mismatched error***\n"                                                 \
+    "The HDF5 header files used to compile this application are not compatible with\n"                       \
+    "the version used by the HDF5 library to which this application is linked.\n"                            \
+    "Data corruption or segmentation faults may occur if the application continues.\n"                       \
+    "This can happen when an application was compiled by one version of HDF5 but\n"                          \
+    "linked with an incompatible version of static or shared HDF5 library.\n"                                \
+    "You should recompile the application or check your shared library related\n"                            \
+    "settings such as 'LD_LIBRARY_PATH'.\n"
 
 herr_t
 H5check_version(unsigned majnum, unsigned minnum, unsigned relnum)
@@ -914,7 +930,8 @@ H5check_version(unsigned majnum, unsigned minnum, unsigned relnum)
             disable_version_check = (unsigned int)HDstrtol(s, NULL, 0);
     }
 
-    if (H5_VERS_MAJOR != majnum || H5_VERS_MINOR != minnum || H5_VERS_RELEASE != relnum) {
+    /* H5_VERS_MAJOR and H5_VERS_MINOR must match */
+    if (H5_VERS_MAJOR != majnum || H5_VERS_MINOR != minnum || H5_VERS_RELEASE > relnum) {
         switch (disable_version_check) {
             case 0:
                 HDfprintf(stderr, "%s%s", version_mismatch_warning,
@@ -949,7 +966,51 @@ H5check_version(unsigned majnum, unsigned minnum, unsigned relnum)
                 break;
         } /* end switch */
 
-    } /* end if */
+    } /* end if (H5_VERS_MAJOR != majnum || H5_VERS_MINOR != minnum || H5_VERS_RELEASE > relnum) */
+
+    /* H5_VERS_RELEASE should be compatible, we will only add checks for exceptions */
+    if (H5_VERS_RELEASE != relnum) {
+        for (unsigned i = 0; i < VERS_RELEASE_EXCEPTIONS_SIZE; i++) {
+            /* Check for incompatible headers or incompatible library */
+            if (VERS_RELEASE_EXCEPTIONS[i] == relnum || VERS_RELEASE_EXCEPTIONS[i] == H5_VERS_RELEASE) {
+                switch (disable_version_check) {
+                    case 0:
+                        HDfprintf(
+                            stderr, "%s%s", version_mismatch_warning,
+                            "You can, at your own risk, disable this warning by setting the environment\n"
+                            "variable 'HDF5_DISABLE_VERSION_CHECK' to a value of '1'.\n"
+                            "Setting it to 2 or higher will suppress the warning messages totally.\n");
+                        /* Mention the versions we are referring to */
+                        HDfprintf(stderr, "Headers are %u.%u.%u, library is %u.%u.%u\n", majnum, minnum,
+                                  relnum, (unsigned)H5_VERS_MAJOR, (unsigned)H5_VERS_MINOR,
+                                  (unsigned)H5_VERS_RELEASE);
+
+                        /* Bail out now. */
+                        HDfputs("Bye...\n", stderr);
+                        HDabort();
+                    case 1:
+                        /* continue with a warning */
+                        /* Note that the warning message is embedded in the format string.*/
+                        HDfprintf(stderr,
+                                  "%s'HDF5_DISABLE_VERSION_CHECK' "
+                                  "environment variable is set to %d, application will\n"
+                                  "continue at your own risk.\n",
+                                  version_mismatch_warning, disable_version_check);
+                        /* Mention the versions we are referring to */
+                        HDfprintf(stderr, "Headers are %u.%u.%u, library is %u.%u.%u\n", majnum, minnum,
+                                  relnum, (unsigned)H5_VERS_MAJOR, (unsigned)H5_VERS_MINOR,
+                                  (unsigned)H5_VERS_RELEASE);
+                        break;
+                    default:
+                        /* 2 or higher: continue silently */
+                        break;
+                } /* end switch */
+
+            } /* end if */
+
+        } /* end for */
+
+    } /* end if (H5_VERS_RELEASE != relnum) */
 
     /* Indicate that the version check has been performed */
     checked = 1;
@@ -991,7 +1052,7 @@ done:
  *              is failing inexplicably, then try calling this function
  *              first.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:    Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
@@ -1010,12 +1071,12 @@ done:
 } /* end H5open() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5atclose
+ * Function:    H5atclose
  *
- * Purpose:	Register a callback for the library to invoke when it's
- *		closing.  Callbacks are invoked in LIFO order.
+ * Purpose:    Register a callback for the library to invoke when it's
+ *        closing.  Callbacks are invoked in LIFO order.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:    Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
@@ -1049,11 +1110,11 @@ done:
 } /* end H5atclose() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5close
+ * Function:    H5close
  *
- * Purpose:	Terminate the library and release all resources.
+ * Purpose:    Terminate the library and release all resources.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:    Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
@@ -1074,9 +1135,9 @@ H5close(void)
 } /* end H5close() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5allocate_memory
+ * Function:    H5allocate_memory
  *
- * Purpose:	    Allocate a memory buffer with the semantics of malloc().
+ * Purpose:        Allocate a memory buffer with the semantics of malloc().
  *
  *              NOTE: This function is intended for use with filter
  *              plugins so that all allocation and free operations
@@ -1114,9 +1175,9 @@ H5allocate_memory(size_t size, hbool_t clear)
 } /* end H5allocate_memory() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5resize_memory
+ * Function:    H5resize_memory
  *
- * Purpose:	    Resize a memory buffer with the semantics of realloc().
+ * Purpose:        Resize a memory buffer with the semantics of realloc().
  *
  *              NOTE: This function is intended for use with filter
  *              plugins so that all allocation and free operations
@@ -1151,14 +1212,14 @@ H5resize_memory(void *mem, size_t size)
 } /* end H5resize_memory() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5free_memory
+ * Function:    H5free_memory
  *
- * Purpose:	    Frees memory allocated by the library that it is the user's
+ * Purpose:        Frees memory allocated by the library that it is the user's
  *              responsibility to free.  Ensures that the same library
  *              that was used to allocate the memory frees it.  Passing
  *              NULL pointers is allowed.
  *
- * Return:	    SUCCEED/FAIL
+ * Return:        SUCCEED/FAIL
  *
  *-------------------------------------------------------------------------
  */
@@ -1175,12 +1236,12 @@ H5free_memory(void *mem)
 } /* end H5free_memory() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5is_library_threadsafe
+ * Function:    H5is_library_threadsafe
  *
- * Purpose:	    Checks to see if the library was built with thread-safety
+ * Purpose:        Checks to see if the library was built with thread-safety
  *              enabled.
  *
- * Return:	    SUCCEED/FAIL
+ * Return:        SUCCEED/FAIL
  *
  *-------------------------------------------------------------------------
  */
@@ -1206,16 +1267,16 @@ H5is_library_threadsafe(hbool_t *is_ts /*out*/)
 } /* end H5is_library_threadsafe() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5is_library_terminating
+ * Function:    H5is_library_terminating
  *
- * Purpose:	Checks to see if the library is shutting down.
+ * Purpose:    Checks to see if the library is shutting down.
  *
- * Note:	Useful for plugins to detect when the library is terminating.
- *		For example, a VOL connector could check if a "file close"
- *		callback was the result of the library shutdown process, or
- *		an API action from the application.
+ * Note:    Useful for plugins to detect when the library is terminating.
+ *        For example, a VOL connector could check if a "file close"
+ *        callback was the result of the library shutdown process, or
+ *        an API action from the application.
  *
- * Return:	SUCCEED/FAIL
+ * Return:    SUCCEED/FAIL
  *
  *-------------------------------------------------------------------------
  */
diff --git a/src/H5private.h b/src/H5private.h
index 7823bfc..802dd90 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -2169,7 +2169,7 @@ H5_DLL herr_t H5CX_pop(hbool_t update_dxpl_props);
  * Use this macro for API functions that shouldn't perform _any_ initialization
  *      of the library or an interface, or push themselves on the function
  *      stack, or perform tracing, etc.  This macro _only_ sanity checks the
- *	API name itself.  Examples are: H5TSmutex_acquire,
+ *    API name itself.  Examples are: H5TSmutex_acquire,
  *
  */
 #define FUNC_ENTER_API_NAMECHECK_ONLY                                                                        \
@@ -2265,7 +2265,7 @@ H5_DLL herr_t H5CX_pop(hbool_t update_dxpl_props);
  * Use this macro for non-API functions that shouldn't perform _any_ initialization
  *      of the library or an interface, or push themselves on the function
  *      stack, or perform tracing, etc.  This macro _only_ sanity checks the
- *	API name itself.  Examples are private routines in the H5TS package.
+ *    API name itself.  Examples are private routines in the H5TS package.
  *
  */
 #define FUNC_ENTER_NOAPI_NAMECHECK_ONLY                                                                      \
@@ -2343,7 +2343,7 @@ H5_DLL herr_t H5CX_pop(hbool_t update_dxpl_props);
  * Use this macro for non-API functions that shouldn't perform _any_ initialization
  *      of the library or an interface, or push themselves on the function
  *      stack, or perform tracing, etc.  This macro _only_ sanity checks the
- *	API name itself.  Examples are static routines in the H5TS package.
+ *    API name itself.  Examples are static routines in the H5TS package.
  *
  */
 #define FUNC_ENTER_STATIC_NAMECHECK_ONLY                                                                     \
diff --git a/test/CMakeTests.cmake b/test/CMakeTests.cmake
index e840559..bb5356d 100644
--- a/test/CMakeTests.cmake
+++ b/test/CMakeTests.cmake
@@ -649,10 +649,10 @@ set_tests_properties (H5TEST-tcheck_version-minor PROPERTIES
     WORKING_DIRECTORY ${HDF5_TEST_BINARY_DIR}/H5TEST
     WILL_FAIL "true"
 )
+# release + 1 should pass
 add_test (NAME H5TEST-tcheck_version-release COMMAND ${CMAKE_CROSSCOMPILING_EMULATOR} $<TARGET_FILE:tcheck_version> "-tr")
 set_tests_properties (H5TEST-tcheck_version-release PROPERTIES
     WORKING_DIRECTORY ${HDF5_TEST_BINARY_DIR}/H5TEST
-    WILL_FAIL "true"
 )
 
 ##############################################################################
diff --git a/test/testcheck_version.sh.in b/test/testcheck_version.sh.in
index 43d1b46..6378ee5 100644
--- a/test/testcheck_version.sh.in
+++ b/test/testcheck_version.sh.in
@@ -15,7 +15,7 @@
 # Tests for the H5check_version function.
 #
 # Programmer: Albert Cheng
-#	      Sep 28, 2009
+#          Sep 28, 2009
 
 srcdir=@srcdir@
 
@@ -24,7 +24,7 @@ srcdir=@srcdir@
 Shared_Lib=@enable_shared@
 Static_Lib=@enable_static@
 Static_exec=@STATIC_EXEC@
-h5haveexitcode=yes	# default is yes
+h5haveexitcode=yes    # default is yes
 
 CMP='cmp -s'
 DIFF='diff -c'
@@ -103,10 +103,10 @@ WarnMesg2(){
 #     mismatch).
 #
 # Expected results:
-# 		Value of $HDF5_DISABLE_VERSION_CHECK
-#		unset	""	-1	0	1	2	3
-# Matched	OK	OK	OK	OK	OK	OK	OK
-# Mismatched	W/A	W/A	W/A	W/A	W2/OK	OK	W2/OK
+#         Value of $HDF5_DISABLE_VERSION_CHECK
+#        unset    ""    -1    0    1    2    3
+# Matched    OK    OK    OK    OK    OK    OK    OK
+# Mismatched    W/A    W/A    W/A    W/A    W2/OK    OK    W2/OK
 # Result codes:
 # OK:    No warning, exit 0.
 # W/A:   Warning, abort and exit non-0.
@@ -130,42 +130,42 @@ TESTING() {
     xxh5versrelease=$h5versrelease
 
     if [ "$h5DisableVersion" = unset ]; then
-	envcmd=""		# noop
+    envcmd=""        # noop
     else
-	envcmd="env HDF5_DISABLE_VERSION_CHECK=$h5DisableVersion"
+    envcmd="env HDF5_DISABLE_VERSION_CHECK=$h5DisableVersion"
     fi
 
     if [ "$wrongversionnumbers" = none ]; then
-	# OK: No warning, exit 0
-	cp /dev/null $expect
-	expect_code=0
+    # OK: No warning, exit 0
+    cp /dev/null $expect
+    expect_code=0
     else
-	arguments=-t"$wrongversionnumbers"
-	# calculate mismatched version numbers by listing.
-	case $wrongversionnumbers in
-	    "M")    xxh5versmajor=`expr $h5versmajor + 1`
-		    ;;
-	    "m")    xxh5versminor=`expr $h5versminor + 1`
-		    ;;
-	    "r")    xxh5versrelease=`expr $h5versrelease + 1`
-		    ;;
-	esac
-	case "$h5DisableVersion" in
-	    1)
-		# W2/OK: Different Warning, exit 0.
-		WarnMesg2 > $expect
-		expect_code=0
-		;;
-	    [2-9]|[1-9][0-9]*)
-		# OK: No warning, exit 0
-		cp /dev/null $expect
-		expect_code=0
-		;;
-	    *)	# W/A:   Warning, abort and exit non-0.
-		WarnMesg > $expect
-		expect_code=6	# Signal Abort exit code (128+6)
-		;;
-	esac
+    arguments=-t"$wrongversionnumbers"
+    # calculate mismatched version numbers by listing.
+    case $wrongversionnumbers in
+        "M")    xxh5versmajor=`expr $h5versmajor + 1`
+            ;;
+        "m")    xxh5versminor=`expr $h5versminor + 1`
+            ;;
+        "r")    xxh5versrelease=`expr $h5versrelease + 1`
+            ;;
+    esac
+    case "$h5DisableVersion" in
+        1)
+        # W2/OK: Different Warning, exit 0.
+        WarnMesg2 > $expect
+        expect_code=0
+        ;;
+        [2-9]|[1-9][0-9]*)
+        # OK: No warning, exit 0
+        cp /dev/null $expect
+        expect_code=0
+        ;;
+        *)    # W/A:   Warning, abort and exit non-0.
+        WarnMesg > $expect
+        expect_code=6    # Signal Abort exit code (128+6)
+        ;;
+    esac
     fi
 
     # Run test.
@@ -177,23 +177,23 @@ TESTING() {
     cat $actual_err >> $actual
 
     if [ $h5haveexitcode = 'yes' -a \( $expect_code -ne $ret_code \) ]; then
-	echo "*FAILED*"
-	echo "    Expected exit code ($expect_code) differs from actual code ($ret_code)"
-	nerrors="`expr $nerrors + 1`"
+    echo "*FAILED*"
+    echo "    Expected exit code ($expect_code) differs from actual code ($ret_code)"
+    nerrors="`expr $nerrors + 1`"
     elif $CMP $expect $actual; then
-	echo " PASSED"
+    echo " PASSED"
     else
-	echo "*FAILED*"
-	echo "    Expected result differs from actual result"
-	nerrors="`expr $nerrors + 1`"
-	test yes = "$verbose" && $DIFF $expect $actual |sed 's/^/    /'
+    echo "*FAILED*"
+    echo "    Expected result differs from actual result"
+    nerrors="`expr $nerrors + 1`"
+    test yes = "$verbose" && $DIFF $expect $actual |sed 's/^/    /'
     fi
 
     # Clean up output file.
     # Also clean the core file generated by H5check_version's abort.
     if test -z "$HDF5_NOCLEANUP"; then
-	$RM $expect $actual $actual_err
-	$RM core
+    $RM $expect $actual $actual_err
+    $RM core
     fi
 }
 
@@ -201,15 +201,15 @@ TESTING() {
 # Echo parameters for debugging if verbose mode is on.
 DEBUGPRINT() {
     if [ -n "$debugmode" ]; then
-	echo $*
+    echo $*
     fi
 }
 
 
 # MAIN Body
 nerrors=0
-verbose=yes	# default on
-debugmode=	# default off
+verbose=yes    # default on
+debugmode=    # default off
 H5_HAVE_EMBEDDED_LIBINFO=`grep '#define H5_HAVE_EMBEDDED_LIBINFO ' ../src/H5pubconf.h`
 h5libsettings=../src/libhdf5.settings
 
@@ -240,13 +240,13 @@ fi
 # Three Categories of tests:
 # Normal: where the version numbers all matched (wrong_version == none).
 # Mismatched version numbers (could be Major or minor version
-#	or release numbers or a combination of all three.)
+#    or release numbers or a combination of all three.)
 # Test all the above with different values of the environment variable,
 # HDF5_DISABLE_VERSION_CHECK, as unset, "", -1, 0, 1, 2, 3
 
 for val_disable_version_check in unset "" -1 0 1 2 3; do
-    for wrong_version in none M m r; do
-	TESTING "$val_disable_version_check" "$wrong_version"
+    for wrong_version in none M m; do
+    TESTING "$val_disable_version_check" "$wrong_version"
     done
 done