Merge pull request #640 in HDFFV/hdf5 from ~BYRN/hdf5_adb:hdf5_1_8 to hdf5_1_8

* commit '5cc911f3ba2c5d12c3305b348610f9ba80c85db2':
  HDFFV-10188 Force non-native type description
  HDFFV-10188 merge fix and tests from develop

16 files changed, 215 insertions, 56 deletions

diff --git a/MANIFEST b/MANIFEST
index 48d8af7..16900d2 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1390,6 +1390,9 @@
 ./tools/testfiles/tgrp_comments.ls
 ./tools/testfiles/tgrp_comments.ddl
 ./tools/testfiles/tgrp_comments.h5
+./tools/testfiles/tgrpnullspace.h5
+./tools/testfiles/tgrpnullspace.ddl
+./tools/testfiles/tgrpnullspace.ls
 ./tools/testfiles/thlink-1.ddl
 ./tools/testfiles/thlink-2.ddl
 ./tools/testfiles/thlink-3.ddl
@@ -1445,6 +1448,7 @@
 ./tools/testfiles/tno-subset.h5
 ./tools/testfiles/tno-subset.ddl
 ./tools/testfiles/tnullspace.h5
+./tools/testfiles/tnullspace.h5.xml
 ./tools/testfiles/tnullspace.ddl
 ./tools/testfiles/tobjref.h5
 ./tools/testfiles/topaque.h5
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index f538aa2..d7381ca 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -120,6 +120,16 @@ Bug Fixes since HDF5-1.8.19
 
     Tools
     -----
+    - h5ls
+
+      h5ls generated error on stack when it encountered a H5S_NULL
+      dataspace.
+
+      Adding checks for H5S_NULL before calling H5Sis_simple (located
+      in the h5tools_dump_mem function) fixed the issue.
+
+      (ADB - 2017/08/17, HDFFV-10188)
+
     - h5dump
 
       h5dump segfaulted on output of XML file.
diff --git a/tools/h5dump/CMakeTests.cmake b/tools/h5dump/CMakeTests.cmake
index 0978265..d930edd 100644
--- a/tools/h5dump/CMakeTests.cmake
+++ b/tools/h5dump/CMakeTests.cmake
@@ -103,6 +103,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup-1.ddl
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup-2.ddl
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrp_comments.ddl
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrpnullspace.ddl
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink-1.ddl
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink-2.ddl
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink-3.ddl
@@ -270,6 +271,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tfvalues.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrp_comments.h5
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrpnullspace.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thyperslab.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tints4dims.h5
@@ -883,6 +885,8 @@
           tgroup-2.out.err
           tgrp_comments.out
           tgrp_comments.out.err
+          tgrpnullspace.out
+          tgrpnullspace.out.err
           thlink-1.out
           thlink-1.out.err
           thlink-2.out
@@ -1389,6 +1393,7 @@
 
   # test for displaying dataset and attribute of null space
   ADD_H5_TEST (tnullspace 0 --enable-error-stack tnullspace.h5)
+  ADD_H5_TEST (tgrpnullspace 0 -p --enable-error-stack tgrpnullspace.h5)
 
   # test for displaying dataset and attribute of space with 0 dimension size
   ADD_H5_TEST (zerodim 0 --enable-error-stack zerodim.h5)
diff --git a/tools/h5dump/CMakeTestsXML.cmake b/tools/h5dump/CMakeTestsXML.cmake
index 595d0b5..9a3b511 100644
--- a/tools/h5dump/CMakeTestsXML.cmake
+++ b/tools/h5dump/CMakeTestsXML.cmake
@@ -53,6 +53,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/test35.nc
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tnestedcomp.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tnodata.h5
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tnullspace.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tobjref.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/topaque.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/torderattr.h5
@@ -117,6 +118,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tname-sp.h5.xml
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tnestedcomp.h5.xml
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tnodata.h5.xml
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tnullspace.h5.xml
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tobjref.h5.xml
       ${HDF5_TOOLS_SRC_DIR}/testfiles/topaque.h5.xml
       ${HDF5_TOOLS_SRC_DIR}/testfiles/torderattr1.h5.xml
@@ -296,6 +298,8 @@
           tnodata.h5.out.err
           tnoname.h5.out
           tnoname.h5.out.err
+          tnullspace.h5.out
+          tnullspace.h5.out.err
           tobjref.h5.out
           tobjref.h5.out.err
           topaque.h5.out
@@ -402,9 +406,7 @@
   ADD_XML_H5_TEST (tsaf.h5 0 tsaf.h5)
   ADD_XML_H5_TEST (tempty.h5 0 tempty.h5)
   ADD_XML_H5_TEST (tnamed_dtype_attr.h5 0 tnamed_dtype_attr.h5)
-  ##Test dataset and attribute of null space.  Commented out:
-  ## wait until the XML schema is updated for null space.
-  ##  ADD_XML_H5_TEST (tnullspace.h5 0 tnulspace.h5)
+  ADD_XML_H5_TEST (tnullspace.h5 0 tnullspace.h5)
   ## So is dataspace with 0 dimension size.
   ##  ADD_XML_H5_TEST (zerodim.h5 0 zerodim.h5)
 
diff --git a/tools/h5dump/h5dump_xml.c b/tools/h5dump/h5dump_xml.c
index ee897ae..089419b 100644
--- a/tools/h5dump/h5dump_xml.c
+++ b/tools/h5dump/h5dump_xml.c
@@ -1958,28 +1958,32 @@ xml_dump_data(hid_t obj_id, int obj_data, struct subset_t H5_ATTR_UNUSED * sset,
             H5Tclose(type);
 
             space = H5Aget_space(obj_id);
+            if(space == H5S_NULL || space == H5S_NO_CLASS) {
+                status = SUCCEED;
+            }
+            else {
+                ndims = H5Sget_simple_extent_dims(space, size, NULL);
 
-            ndims = H5Sget_simple_extent_dims(space, size, NULL);
+                for (i = 0; i < ndims; i++)
+                    nelmts *= size[i];
 
-            for (i = 0; i < ndims; i++)
-                nelmts *= size[i];
+                buf = HDmalloc((size_t)(nelmts * MAX(H5Tget_size(type), H5Tget_size(p_type))));
+                HDassert(buf);
 
-            buf = HDmalloc((size_t)(nelmts * MAX(H5Tget_size(type), H5Tget_size(p_type))));
-            HDassert(buf);
+                if (H5Aread(obj_id, p_type, buf) >= 0) {
+                    h5tools_context_t datactx;
+                    HDmemset(&datactx, 0, sizeof(datactx));
+                    datactx.need_prefix = TRUE;
+                    datactx.indent_level = ctx.indent_level;
+                    datactx.cur_column = ctx.cur_column;
+                    status = h5tools_dump_mem(rawoutstream, outputformat, &datactx, obj_id, p_type, space, buf);
+                }
+                /* Reclaim any VL memory, if necessary */
+                if (vl_data)
+                    H5Dvlen_reclaim(p_type, space, H5P_DEFAULT, buf);
 
-            if (H5Aread(obj_id, p_type, buf) >= 0) {
-                h5tools_context_t datactx;
-                HDmemset(&datactx, 0, sizeof(datactx));
-                datactx.need_prefix = TRUE;
-                datactx.indent_level = ctx.indent_level;
-                datactx.cur_column = ctx.cur_column;
-                status = h5tools_dump_mem(rawoutstream, outputformat, &datactx, obj_id, p_type, space, buf);
+                HDfree(buf);
             }
-            /* Reclaim any VL memory, if necessary */
-            if (vl_data)
-                H5Dvlen_reclaim(p_type, space, H5P_DEFAULT, buf);
-
-            HDfree(buf);
             H5Tclose(p_type);
             H5Sclose(space);
             H5Tclose(type);
diff --git a/tools/h5dump/h5dumpgentest.c b/tools/h5dump/h5dumpgentest.c
index c74e800..f9450cb 100644
--- a/tools/h5dump/h5dumpgentest.c
+++ b/tools/h5dump/h5dumpgentest.c
@@ -112,6 +112,7 @@
 #define FILE82  "tcompound_complex2.h5"
 #define FILE83  "tvlenstr_array.h5"
 #define FILE84  "tudfilter.h5"
+#define FILE85  "tgrpnullspace.h5"
 
 /*-------------------------------------------------------------------------
  * prototypes
@@ -10289,6 +10290,43 @@ H5Z_filter_dynlibud(unsigned int flags, size_t cd_nelmts,
  *-------------------------------------------------------------------------
  */
 
+/*-------------------------------------------------------------------------
+ * Function: gent_null_space_group
+ *
+ * Purpose: generates dataset and attribute of null dataspace in a group
+ *-------------------------------------------------------------------------
+ */
+static void gent_null_space_group(void)
+{
+    hid_t fid, root, group, dataset, space, attr;
+    int dset_buf = 10;
+    int point = 4;
+
+    fid = H5Fcreate(FILE85, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    root = H5Gopen2(fid, "/", H5P_DEFAULT);
+
+    group = H5Gcreate2(fid, "/g1", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+
+    /* null space */
+    space = H5Screate(H5S_NULL);
+
+    /* dataset */
+    dataset = H5Dcreate2(group, "dset", H5T_STD_I32BE, space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    /* nothing should be written */
+    H5Dwrite(dataset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &dset_buf);
+
+    /* attribute */
+    attr = H5Acreate2(group, "attr", H5T_NATIVE_UINT, space, H5P_DEFAULT, H5P_DEFAULT);
+    H5Awrite(attr, H5T_NATIVE_INT, &point); /* Nothing can be written */
+
+    H5Dclose(dataset);
+    H5Aclose(attr);
+    H5Gclose(group);
+    H5Gclose(root);
+    H5Sclose(space);
+    H5Fclose(fid);
+}
+
 int main(void)
 {
     gent_group();
@@ -10376,6 +10414,7 @@ int main(void)
     gent_bitnopaquefields();
 
     gent_intsfourdims();
+    gent_null_space_group();
 
     gent_udfilter();
 
diff --git a/tools/h5dump/testh5dump.sh.in b/tools/h5dump/testh5dump.sh.in
index f941afc..9ceffa5 100644
--- a/tools/h5dump/testh5dump.sh.in
+++ b/tools/h5dump/testh5dump.sh.in
@@ -131,6 +131,7 @@ $SRC_H5DUMP_TESTFILES/tfpformat.h5
 $SRC_H5DUMP_TESTFILES/tfvalues.h5
 $SRC_H5DUMP_TESTFILES/tgroup.h5
 $SRC_H5DUMP_TESTFILES/tgrp_comments.h5
+$SRC_H5DUMP_TESTFILES/tgrpnullspace.h5
 $SRC_H5DUMP_TESTFILES/thlink.h5
 $SRC_H5DUMP_TESTFILES/thyperslab.h5
 $SRC_H5DUMP_TESTFILES/tintsattrs.h5
@@ -258,6 +259,7 @@ $SRC_H5DUMP_TESTFILES/tfpformat.ddl
 $SRC_H5DUMP_TESTFILES/tgroup-1.ddl
 $SRC_H5DUMP_TESTFILES/tgroup-2.ddl
 $SRC_H5DUMP_TESTFILES/tgrp_comments.ddl
+$SRC_H5DUMP_TESTFILES/tgrpnullspace.ddl
 $SRC_H5DUMP_TESTFILES/thlink-1.ddl
 $SRC_H5DUMP_TESTFILES/thlink-2.ddl
 $SRC_H5DUMP_TESTFILES/thlink-3.ddl
@@ -1265,6 +1267,7 @@ TOOLTEST thyperslab.ddl --enable-error-stack thyperslab.h5
 
 # test for displaying dataset and attribute of null space
 TOOLTEST tnullspace.ddl --enable-error-stack tnullspace.h5
+TOOLTEST tgrpnullspace.ddl -p --enable-error-stack tgrpnullspace.h5
 
 # test for displaying dataset and attribute of space with 0 dimension size
 TOOLTEST zerodim.ddl --enable-error-stack zerodim.h5
diff --git a/tools/h5dump/testh5dumpxml.sh.in b/tools/h5dump/testh5dumpxml.sh.in
index 64dd737..8aa8811 100644
--- a/tools/h5dump/testh5dumpxml.sh.in
+++ b/tools/h5dump/testh5dumpxml.sh.in
@@ -97,6 +97,7 @@ $SRC_H5DUMP_TESTFILES/tname-sp.h5
 $SRC_H5DUMP_TESTFILES/tnamed_dtype_attr.h5
 $SRC_H5DUMP_TESTFILES/tnestedcomp.h5
 $SRC_H5DUMP_TESTFILES/tnodata.h5
+$SRC_H5DUMP_TESTFILES/tnullspace.h5
 $SRC_H5DUMP_TESTFILES/tobjref.h5
 $SRC_H5DUMP_TESTFILES/topaque.h5
 $SRC_H5DUMP_TESTFILES/torderattr.h5
@@ -162,6 +163,7 @@ $SRC_H5DUMP_TESTFILES/tname-quot.h5.xml
 $SRC_H5DUMP_TESTFILES/tname-sp.h5.xml
 $SRC_H5DUMP_TESTFILES/tnestedcomp.h5.xml
 $SRC_H5DUMP_TESTFILES/tnodata.h5.xml
+$SRC_H5DUMP_TESTFILES/tnullspace.h5.xml
 $SRC_H5DUMP_TESTFILES/tobjref.h5.xml
 $SRC_H5DUMP_TESTFILES/topaque.h5.xml
 $SRC_H5DUMP_TESTFILES/torderattr1.h5.xml
@@ -355,9 +357,7 @@ TOOLTEST tvlstr.h5.xml --xml tvlstr.h5
 TOOLTEST tsaf.h5.xml --xml tsaf.h5
 TOOLTEST tempty.h5.xml --xml tempty.h5
 TOOLTEST tnamed_dtype_attr.h5.xml --xml tnamed_dtype_attr.h5
-##Test dataset and attribute of null space.  Commented out:
-## wait until the XML schema is updated for null space.
-##TOOLTEST tnullspace.h5.xml --xml tnulspace.h5
+TOOLTEST tnullspace.h5.xml --xml tnullspace.h5
 
 # other options for xml
 
diff --git a/tools/h5ls/CMakeTests.cmake b/tools/h5ls/CMakeTests.cmake
index 343949a..a839518 100644
--- a/tools/h5ls/CMakeTests.cmake
+++ b/tools/h5ls/CMakeTests.cmake
@@ -33,6 +33,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/textlinktar.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrp_comments.h5
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrpnullspace.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tloop.h5
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tnestedcomp.h5
@@ -88,6 +89,7 @@
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup-1.ls
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup-2.ls
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tgroup-3.ls
+      ${HDF5_TOOLS_SRC_DIR}/testfiles/tgrpnullspace.ls
       ${HDF5_TOOLS_SRC_DIR}/testfiles/thlink-1.ls
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tloop-1.ls
       ${HDF5_TOOLS_SRC_DIR}/testfiles/tmultifile.ls
@@ -239,6 +241,8 @@
           textlinksrc-7-old.out.err
           tgrp_comments.out
           tgrp_comments.out.err
+          tgrpnullspace.out
+          tgrpnullspace.out.err
           tsoftlinks-1.out
           tsoftlinks-1.out.err
           tsoftlinks-2.out
@@ -413,6 +417,9 @@
   # test for empty data
   ADD_H5_TEST (tempty 0 -w80 -d tempty.h5)
 
+ # test for displaying dataset and attribute of null space
+  ADD_H5_TEST (tgrpnullspace 0 -w80 -v -S tgrpnullspace.h5)
+
   # test for all dataset types written to attributes
   # enable -S for avoiding printing NATIVE types
   ADD_H5_TEST (tattr2 0 -w80 -v -S tattr2.h5)
diff --git a/tools/h5ls/h5ls.c b/tools/h5ls/h5ls.c
index 7daf7e3..a58b96b 100644
--- a/tools/h5ls/h5ls.c
+++ b/tools/h5ls/h5ls.c
@@ -1616,38 +1616,40 @@ list_attr(hid_t obj, const char *attr_name, const H5A_info_t H5_ATTR_UNUSED *ain
 
         info = &outputformat;
 
-        if(hexdump_g)
-           p_type = H5Tcopy(type);
-        else
-           p_type = H5Tget_native_type(type, H5T_DIR_DEFAULT);
-
-        if(p_type >= 0) {
-            /* VL data special information */
-            unsigned int        vl_data = 0; /* contains VL datatypes */
-
-            /* Check if we have VL data in the dataset's datatype */
-            if (h5tools_detect_vlen(p_type) == TRUE)
-                vl_data = TRUE;
-
-            temp_need= nelmts * MAX(H5Tget_size(type), H5Tget_size(p_type));
-            HDassert(temp_need == (hsize_t)((size_t)temp_need));
-            need = (size_t)temp_need;
-            buf = HDmalloc(need);
-            HDassert(buf);
-            if(H5Aread(attr, p_type, buf) >= 0) {
-                ctx.need_prefix = TRUE;
-                ctx.indent_level = 2;
-                ctx.cur_column = (size_t)curr_pos;
-                h5tools_dump_mem(rawoutstream, info, &ctx, attr, p_type, space, buf);
-            }
+        if(space_type != H5S_NULL && space_type != H5S_NO_CLASS) {
+            if(hexdump_g)
+            p_type = H5Tcopy(type);
+            else
+            p_type = H5Tget_native_type(type, H5T_DIR_DEFAULT);
+
+            if(p_type >= 0) {
+                /* VL data special information */
+                unsigned int        vl_data = 0; /* contains VL datatypes */
+
+                /* Check if we have VL data in the dataset's datatype */
+                if (h5tools_detect_vlen(p_type) == TRUE)
+                    vl_data = TRUE;
+
+                temp_need= nelmts * MAX(H5Tget_size(type), H5Tget_size(p_type));
+                HDassert(temp_need == (hsize_t)((size_t)temp_need));
+                need = (size_t)temp_need;
+                buf = HDmalloc(need);
+                HDassert(buf);
+                if(H5Aread(attr, p_type, buf) >= 0) {
+                    ctx.need_prefix = TRUE;
+                    ctx.indent_level = 2;
+                    ctx.cur_column = (size_t)curr_pos;
+                    h5tools_dump_mem(rawoutstream, info, &ctx, attr, p_type, space, buf);
+                }
 
-            /* Reclaim any VL memory, if necessary */
-            if (vl_data)
-                H5Dvlen_reclaim(p_type, space, H5P_DEFAULT, buf);
+                /* Reclaim any VL memory, if necessary */
+                if (vl_data)
+                    H5Dvlen_reclaim(p_type, space, H5P_DEFAULT, buf);
 
-            HDfree(buf);
-            H5Tclose(p_type);
-        } /* end if */
+                HDfree(buf);
+                H5Tclose(p_type);
+            } /* end if */
+        }
 
         H5Sclose(space);
         H5Tclose(type);
diff --git a/tools/h5ls/testh5ls.sh.in b/tools/h5ls/testh5ls.sh.in
index 4b57acc..40bb529 100644
--- a/tools/h5ls/testh5ls.sh.in
+++ b/tools/h5ls/testh5ls.sh.in
@@ -80,6 +80,7 @@ $SRC_H5LS_TESTFILES/textlinksrc.h5
 $SRC_H5LS_TESTFILES/textlinktar.h5
 $SRC_H5LS_TESTFILES/tgroup.h5
 $SRC_H5LS_TESTFILES/tgrp_comments.h5
+$SRC_H5LS_TESTFILES/tgrpnullspace.h5
 $SRC_H5LS_TESTFILES/thlink.h5
 $SRC_H5LS_TESTFILES/tloop.h5
 $SRC_H5LS_TESTFILES/tnestedcomp.h5
@@ -134,6 +135,7 @@ $SRC_H5LS_TESTFILES/tgroup.ls
 $SRC_H5LS_TESTFILES/tgroup-1.ls
 $SRC_H5LS_TESTFILES/tgroup-2.ls
 $SRC_H5LS_TESTFILES/tgroup-3.ls
+$SRC_H5LS_TESTFILES/tgrpnullspace.ls
 $SRC_H5LS_TESTFILES/thlink-1.ls
 $SRC_H5LS_TESTFILES/tloop-1.ls
 $SRC_H5LS_TESTFILES/tmultifile.ls
@@ -390,6 +392,9 @@ TOOLTEST tarray1.ls 0 -w80 -r -d tarray1.h5
 # test for empty data
 TOOLTEST tempty.ls 0 -w80 -d tempty.h5
 
+# test for displaying dataset and attribute of null space
+TOOLTEST tgrpnullspace.ls 0 -w80 -v -S tgrpnullspace.h5
+
 # test for all dataset types written to attributes
 # enable -S for avoiding printing NATIVE types
 TOOLTEST tattr2.ls 0 -w80 -v -S tattr2.h5
diff --git a/tools/lib/h5tools_ref.c b/tools/lib/h5tools_ref.c
index 85850e3..16a949d 100644
--- a/tools/lib/h5tools_ref.c
+++ b/tools/lib/h5tools_ref.c
@@ -11,8 +11,6 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-#include <stdio.h>
-#include <stdlib.h>
 #include "h5tools_ref.h"
 #include "H5private.h"
 #include "H5SLprivate.h"
@@ -166,7 +164,8 @@ haddr_t
 ref_path_table_lookup(const char *thepath)
 {
     H5O_info_t  oi;
-
+    if((HDstrlen(thepath) == 0) || (thepath == NULL))
+        return HADDR_UNDEF;
     /* Allow lookups on the root group, even though it doesn't have any link info */
     if(HDstrcmp(thepath, "/")) {
         H5L_info_t  li;
diff --git a/tools/testfiles/tgrpnullspace.ddl b/tools/testfiles/tgrpnullspace.ddl
new file mode 100644
index 0000000..2b91527
--- /dev/null
+++ b/tools/testfiles/tgrpnullspace.ddl
@@ -0,0 +1,33 @@
+HDF5 "tgrpnullspace.h5" {
+GROUP "/" {
+   GROUP "g1" {
+      ATTRIBUTE "attr" {
+         DATATYPE  H5T_STD_U32LE
+         DATASPACE  NULL
+         DATA {
+         }
+      }
+      DATASET "dset" {
+         DATATYPE  H5T_STD_I32BE
+         DATASPACE  NULL
+         STORAGE_LAYOUT {
+            CONTIGUOUS
+            SIZE 0
+            OFFSET 18446744073709551615
+         }
+         FILTERS {
+            NONE
+         }
+         FILLVALUE {
+            FILL_TIME H5D_FILL_TIME_IFSET
+            VALUE  H5D_FILL_VALUE_DEFAULT
+         }
+         ALLOCATION_TIME {
+            H5D_ALLOC_TIME_LATE
+         }
+         DATA {
+         }
+      }
+   }
+}
+}
diff --git a/tools/testfiles/tgrpnullspace.h5 b/tools/testfiles/tgrpnullspace.h5
new file mode 100644
index 0000000..82a405e
--- /dev/null
+++ b/tools/testfiles/tgrpnullspace.h5
diff --git a/tools/testfiles/tgrpnullspace.ls b/tools/testfiles/tgrpnullspace.ls
new file mode 100644
index 0000000..439414c
--- /dev/null
+++ b/tools/testfiles/tgrpnullspace.ls
@@ -0,0 +1,7 @@
+Opened "tgrpnullspace.h5" with sec2 driver.
+g1                       Group
+    Attribute: attr null
+        Type:      32-bit little-endian unsigned integer
+
+    Location:  1:800
+    Links:     1
diff --git a/tools/testfiles/tnullspace.h5.xml b/tools/testfiles/tnullspace.h5.xml
new file mode 100644
index 0000000..b1c1974
--- /dev/null
+++ b/tools/testfiles/tnullspace.h5.xml
@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<hdf5:HDF5-File xmlns:hdf5="http://hdfgroup.org/HDF5/XML/schema/HDF5-File.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://hdfgroup.org/HDF5/XML/schema/HDF5-File http://www.hdfgroup.org/HDF5/XML/schema/HDF5-File.xsd">
+<hdf5:RootGroup OBJ-XID="xid_928" H5Path="/">
+   <hdf5:Attribute Name="attr">
+      <hdf5:Dataspace>
+         <!-- unknown dataspace -->
+      </hdf5:Dataspace>
+      <hdf5:DataType>
+         <hdf5:AtomicType>
+            <hdf5:IntegerType ByteOrder="LE" Sign="false" Size="4" />
+         </hdf5:AtomicType>
+      </hdf5:DataType>
+      <hdf5:Data>
+         <hdf5:NoData/>
+      </hdf5:Data>
+   </hdf5:Attribute>
+   <hdf5:Dataset Name="dset" OBJ-XID="xid_976" H5Path= "/dset" Parents="xid_928" H5ParentPaths="/">
+      <hdf5:StorageLayout>
+         <hdf5:ContiguousLayout/>
+      </hdf5:StorageLayout>
+      <hdf5:FillValueInfo FillTime="FillIfSet" AllocationTime="Late">
+         <hdf5:FillValue>
+            <hdf5:NoFill/>
+         </hdf5:FillValue>
+      </hdf5:FillValueInfo>
+      <hdf5:Dataspace>
+         <!-- unknown dataspace -->
+      </hdf5:Dataspace>
+      <hdf5:DataType>
+         <hdf5:AtomicType>
+            <hdf5:IntegerType ByteOrder="BE" Sign="true" Size="4" />
+         </hdf5:AtomicType>
+      </hdf5:DataType>
+      <hdf5:Data>
+         <hdf5:NoData/>
+      </hdf5:Data>
+   </hdf5:Dataset>
+</hdf5:RootGroup>
+</hdf5:HDF5-File>