[svn-r22176] Purpose:

  Fix for HDFFV-7644 GMQS: h5diff - incorrect behaviors when comparing HDF5 files with different type of objects (dataset, group, type) as common objects

Description:
  Fixed failure for comparing same named object with different object types in comparing groups. (common object comparison)
  Prior to the fix, h5diff resulted in error. After the fix, h5diff detects such case as non-comparable and display messages accordingly.
  Test cases were added and tagged with jira#.

Tested:
  jam (linux32-LE), koala (linux64-LE), ostrich (linuxppc64-BE), tejeda (mac32-LE), linew (solaris-BE),  Windows (32-LE cmake), Cmake (jam)

20 files changed, 313 insertions, 291 deletions

diff --git a/MANIFEST b/MANIFEST
index fe3a612..b1c207d 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1815,6 +1815,8 @@
 ./tools/h5diff/testfiles/h5diff_220.txt
 ./tools/h5diff/testfiles/h5diff_221.txt
 ./tools/h5diff/testfiles/h5diff_222.txt
+./tools/h5diff/testfiles/h5diff_223.txt
+./tools/h5diff/testfiles/h5diff_224.txt
 ./tools/h5diff/testfiles/h5diff_300.txt
 ./tools/h5diff/testfiles/h5diff_400.txt
 ./tools/h5diff/testfiles/h5diff_401.txt
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index e2ab4ce..a4633b0 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -691,6 +691,10 @@ Bug Fixes since HDF5-1.8.0 release
 
     Tools
     -----
+        - h5diff: Fixed failure for comparing same named object with different
+          object types in comparing groups. Prior to the fix, h5diff resulted
+          in error. After the fix, h5diff detects such case as non-comparable
+          and display messages accordingly. HDFFV-7664 (JKM 2012/03/28)
         - h5diff: If unique objects exists only in one file and try to exclude
           the unique objects with --exclude-path option, h5diff missed 
           excluding some objects. 
diff --git a/tools/h5diff/CMakeLists.txt b/tools/h5diff/CMakeLists.txt
index dfd1800..da2aaf9 100644
--- a/tools/h5diff/CMakeLists.txt
+++ b/tools/h5diff/CMakeLists.txt
@@ -84,6 +84,8 @@ IF (BUILD_TESTING)
       h5diff_220.txt
       h5diff_221.txt
       h5diff_222.txt
+      h5diff_223.txt
+      h5diff_224.txt
       h5diff_21.txt
       h5diff_22.txt
       h5diff_23.txt
@@ -577,6 +579,10 @@ IF (BUILD_TESTING)
           h5diff_221.out.err
           h5diff_222.out
           h5diff_222.out.err
+          h5diff_223.out
+          h5diff_223.out.err
+          h5diff_224.out
+          h5diff_224.out.err
           h5diff_21.out
           h5diff_21.out.err
           h5diff_22.out
@@ -1164,6 +1170,12 @@ ADD_H5_TEST (h5diff_221 1 -c non_comparables1.h5 non_comparables2.h5 /g2)
 # All the rest comparables should display differences
 ADD_H5_TEST (h5diff_222 1 -c non_comparables1.h5 non_comparables2.h5)
 
+# non-comparable test for common objects (same name) with different object types
+# (HDFFV-7644)
+ADD_H5_TEST (h5diff_223 0 -c non_comparables1.h5 non_comparables2.h5 /diffobjtypes)
+# swap files
+ADD_H5_TEST (h5diff_224 0 -c non_comparables2.h5 non_comparables1.h5 /diffobjtypes)
+
 # ##############################################################################
 # # Links compare without --follow-symlinks nor --no-dangling-links
 # ##############################################################################
diff --git a/tools/h5diff/h5diffgentest.c b/tools/h5diff/h5diffgentest.c
index b57c98a..0b8b4cf 100644
--- a/tools/h5diff/h5diffgentest.c
+++ b/tools/h5diff/h5diffgentest.c
@@ -155,7 +155,8 @@ static void test_comps_array (const char *fname, const char *dset, const char *a
 static void test_comps_vlen (const char *fname, const char *dset,const char *attr, int diff, int is_file_new);
 static void test_comps_array_vlen (const char *fname, const char *dset, const char *attr, int diff, int is_file_new);
 static void test_comps_vlen_arry (const char *fname, const char *dset,const char *attr, int diff, int is_file_new);
-static void test_non_comparables (const char *fname, int diff);
+static void test_data_nocomparables (const char *fname, int diff);
+static void test_objs_nocomparables (const char *fname1, const char *fname2);
 
 /* called by test_attributes() and test_datasets() */
 static void write_attr_in(hid_t loc_id,const char* dset_name,hid_t fid,int make_diffs);
@@ -250,8 +251,11 @@ int main(void)
      * comparable datasets and attributes.  All the comparables should display 
      * differences.
      */
-    test_non_comparables(NON_COMPARBLES1,0);
-    test_non_comparables(NON_COMPARBLES2,5);
+    test_data_nocomparables(NON_COMPARBLES1,0);
+    test_data_nocomparables(NON_COMPARBLES2,5);
+
+    /* common objects (same name) with different object types. HDFFV-7644 */
+    test_objs_nocomparables(NON_COMPARBLES1, NON_COMPARBLES2);
 
     return 0;
 }
@@ -4787,7 +4791,7 @@ static void test_comps_vlen_arry (const char * fname, const char *dset, const ch
 
 
 /*-------------------------------------------------------------------------
-* Function: test_non_comparables
+* Function: test_data_nocomparables
 *
 * Purpose: 
 *   Create test files with non-comparable dataset and attributes with 
@@ -4796,7 +4800,7 @@ static void test_comps_vlen_arry (const char * fname, const char *dset, const ch
 *
 *-------------------------------------------------------------------------*/
 #define DIM_ARRY 3
-static void test_non_comparables (const char * fname, int make_diffs)
+static void test_data_nocomparables (const char * fname, int make_diffs)
 {
     hid_t   fid=0;
     hid_t   gid1=0;
@@ -4998,6 +5002,155 @@ out:
 }
 
 /*-------------------------------------------------------------------------
+* Function: test_objs_nocomparables
+*
+* Purpose: 
+*   Create test files with common objects (same name) but different object
+*   types. 
+*   h5diff should show non-comparable output from these common objects.
+*-------------------------------------------------------------------------*/
+static void test_objs_nocomparables(const char *fname1, const char *fname2)
+{
+    herr_t  status = SUCCEED;
+    hid_t   fid1=0;
+    hid_t   fid2=0;
+    hid_t   topgid1=0;
+    hid_t   topgid2=0;
+    hid_t   gid1=0;
+    hid_t   did1=0;
+    hid_t   tid1=0;
+    hid_t   gid2=0;
+    hid_t   did2=0;
+    hid_t   tid2=0;
+    hsize_t dims[1] = {DIM_ARRY};
+    int data1[DIM_ARRY] = {1,1,1};
+    int data2[DIM_ARRY] = {2,2,2};
+
+   /*-----------------------------------------------------------------------
+    * Open file(s) to add objects
+    *------------------------------------------------------------------------*/
+    /* file1 */
+    fid1 = H5Fopen (fname1, H5F_ACC_RDWR, H5P_DEFAULT);
+    if (fid1 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Fopen failed.\n", fname1);
+        status = FAIL;
+        goto out;
+    }
+
+    /* file2 */
+    fid2 = H5Fopen (fname2, H5F_ACC_RDWR, H5P_DEFAULT);
+    if (fid2 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Fopen failed.\n", fname2);
+        status = FAIL;
+        goto out;
+    }
+
+    /*-----------------------------------------------------------------------
+    * in file1 : add member objects
+    *------------------------------------------------------------------------*/
+    /* parent group */
+    topgid1 = H5Gcreate2(fid1, "diffobjtypes", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (topgid1 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Gcreate2 failed.\n", fname1);
+        status = FAIL;
+        goto out;
+    }
+
+    /* dataset */
+    status = write_dset(topgid1, 1, dims,"obj1", H5T_NATIVE_INT, data1);
+    if (status == FAIL)
+    {
+        fprintf(stderr, "Error: %s> write_dset failed\n", fname1);
+        goto out;
+    }
+
+    /* group */
+    gid1 = H5Gcreate2(topgid1, "obj2", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (gid1 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Gcreate2 failed.\n", fname1);
+        status = FAIL;
+        goto out;
+    }
+
+    /* committed type */
+    tid1 = H5Tcopy(H5T_NATIVE_INT);
+    status = H5Tcommit2(topgid1, "obj3", tid1, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (status < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Tcommit2 failed.\n", fname1);
+        goto out;
+    }
+
+    /*-----------------------------------------------------------------------
+    * in file2 : add member objects
+    *------------------------------------------------------------------------*/
+    /* parent group */
+    topgid2 = H5Gcreate2(fid2, "diffobjtypes", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (topgid2 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Gcreate2 failed.\n", fname2);
+        status = FAIL;
+        goto out;
+    }
+
+    /* group */
+    gid2 = H5Gcreate2(topgid2, "obj1", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (gid2 < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Gcreate2 failed.\n", fname2);
+        status = FAIL;
+        goto out;
+    }
+
+    /* committed type */
+    tid2 = H5Tcopy(H5T_NATIVE_INT);
+    status = H5Tcommit2(topgid2, "obj2", tid2, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+    if (status < 0)
+    {
+        fprintf(stderr, "Error: %s> H5Tcommit2 failed.\n", fname2);
+        goto out;
+    }
+
+    /* dataset */
+    status = write_dset(topgid2, 1, dims,"obj3", H5T_NATIVE_INT, data2);
+    if (status == FAIL)
+    {
+        fprintf(stderr, "Error: %s> write_dset failed\n", fname2);
+        goto out;
+    }
+
+out:
+    /*-----------------------------------------------------------------------
+    * Close IDs
+    *-----------------------------------------------------------------------*/
+    if(fid1)
+        H5Fclose(fid1);
+    if(fid2)
+        H5Fclose(fid2);
+    if(topgid1)
+        H5Gclose(topgid1);
+    if(topgid2)
+        H5Gclose(topgid2);
+    if(did1)
+        H5Dclose(did1);
+    if(did2)
+        H5Dclose(did2);
+    if(gid1)
+        H5Gclose(gid1);
+    if(gid2)
+        H5Gclose(gid2);
+    if(tid1)
+        H5Tclose(tid1);
+    if(tid2)
+        H5Tclose(tid2);
+
+}
+
+/*-------------------------------------------------------------------------
 * Function: write_attr_in
 *
 * Purpose: write attributes in LOC_ID (dataset, group, named datatype)
diff --git a/tools/h5diff/testfiles/h5diff_20.txt b/tools/h5diff/testfiles/h5diff_20.txt
index 3edb543..09c20cb 100644
--- a/tools/h5diff/testfiles/h5diff_20.txt
+++ b/tools/h5diff/testfiles/h5diff_20.txt
@@ -1,4 +1,4 @@
-</dset> is of type H5G_DATASET and </g1> is of type H5G_GROUP
+Not comparable: </dset> is of type H5G_DATASET and </g1> is of type H5G_GROUP
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_21.txt b/tools/h5diff/testfiles/h5diff_21.txt
index 1479457..1c625fe 100644
--- a/tools/h5diff/testfiles/h5diff_21.txt
+++ b/tools/h5diff/testfiles/h5diff_21.txt
@@ -1,4 +1,4 @@
-</dset> is of type H5G_DATASET and </l1> is of type H5G_LINK
+Not comparable: </dset> is of type H5G_DATASET and </l1> is of type H5G_LINK
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_22.txt b/tools/h5diff/testfiles/h5diff_22.txt
index 3ccb06b..2ef22d0 100644
--- a/tools/h5diff/testfiles/h5diff_22.txt
+++ b/tools/h5diff/testfiles/h5diff_22.txt
@@ -1,4 +1,4 @@
-</dset> is of type H5G_DATASET and </t1> is of type H5G_TYPE
+Not comparable: </dset> is of type H5G_DATASET and </t1> is of type H5G_TYPE
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_222.txt b/tools/h5diff/testfiles/h5diff_222.txt
index bdecb8a..53c9464 100644
--- a/tools/h5diff/testfiles/h5diff_222.txt
+++ b/tools/h5diff/testfiles/h5diff_222.txt
@@ -1,3 +1,6 @@
+Not comparable: </diffobjtypes/obj1> is of type H5G_DATASET and </diffobjtypes/obj1> is of type H5G_GROUP
+Not comparable: </diffobjtypes/obj2> is of type H5G_GROUP and </diffobjtypes/obj2> is of type H5G_TYPE
+Not comparable: </diffobjtypes/obj3> is of type H5G_TYPE and </diffobjtypes/obj3> is of type H5G_DATASET
 Not comparable: </g1/dset1> is of class H5T_INTEGER and </g1/dset1> is of class H5T_STRING
 attribute: <attr of </g1/dset1>> and <attr of </g1/dset1>>
 3 differences found
diff --git a/tools/h5diff/testfiles/h5diff_223.txt b/tools/h5diff/testfiles/h5diff_223.txt
new file mode 100644
index 0000000..c8e0f65
--- /dev/null
+++ b/tools/h5diff/testfiles/h5diff_223.txt
@@ -0,0 +1,4 @@
+Not comparable: </diffobjtypes/obj1> is of type H5G_DATASET and </diffobjtypes/obj1> is of type H5G_GROUP
+Not comparable: </diffobjtypes/obj2> is of type H5G_GROUP and </diffobjtypes/obj2> is of type H5G_TYPE
+Not comparable: </diffobjtypes/obj3> is of type H5G_TYPE and </diffobjtypes/obj3> is of type H5G_DATASET
+EXIT CODE: 0
diff --git a/tools/h5diff/testfiles/h5diff_224.txt b/tools/h5diff/testfiles/h5diff_224.txt
new file mode 100644
index 0000000..a4ebedb
--- /dev/null
+++ b/tools/h5diff/testfiles/h5diff_224.txt
@@ -0,0 +1,4 @@
+Not comparable: </diffobjtypes/obj1> is of type H5G_GROUP and </diffobjtypes/obj1> is of type H5G_DATASET
+Not comparable: </diffobjtypes/obj2> is of type H5G_TYPE and </diffobjtypes/obj2> is of type H5G_GROUP
+Not comparable: </diffobjtypes/obj3> is of type H5G_DATASET and </diffobjtypes/obj3> is of type H5G_TYPE
+EXIT CODE: 0
diff --git a/tools/h5diff/testfiles/h5diff_505.txt b/tools/h5diff/testfiles/h5diff_505.txt
index a220730..607b99b 100644
--- a/tools/h5diff/testfiles/h5diff_505.txt
+++ b/tools/h5diff/testfiles/h5diff_505.txt
@@ -1,4 +1,4 @@
-</grp1> is of type H5G_GROUP and </slink_grp1> is of type H5G_LINK
+Not comparable: </grp1> is of type H5G_GROUP and </slink_grp1> is of type H5G_LINK
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_507.txt b/tools/h5diff/testfiles/h5diff_507.txt
index 6176f3f..06b7fe6 100644
--- a/tools/h5diff/testfiles/h5diff_507.txt
+++ b/tools/h5diff/testfiles/h5diff_507.txt
@@ -1,4 +1,4 @@
-</grp1> is of type H5G_GROUP and </elink_grp1> is of type H5G_UDLINK
+Not comparable: </grp1> is of type H5G_GROUP and </elink_grp1> is of type H5G_UDLINK
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_509.txt b/tools/h5diff/testfiles/h5diff_509.txt
index a51ab35..2e3e87a 100644
--- a/tools/h5diff/testfiles/h5diff_509.txt
+++ b/tools/h5diff/testfiles/h5diff_509.txt
@@ -1,4 +1,4 @@
-</slink_grp1> is of type H5G_LINK and </elink_grp1> is of type H5G_UDLINK
+Not comparable: </slink_grp1> is of type H5G_LINK and </elink_grp1> is of type H5G_UDLINK
 --------------------------------
 Some objects are not comparable
 --------------------------------
diff --git a/tools/h5diff/testfiles/h5diff_515.txt b/tools/h5diff/testfiles/h5diff_515.txt
index 077d463..263441d 100644
--- a/tools/h5diff/testfiles/h5diff_515.txt
+++ b/tools/h5diff/testfiles/h5diff_515.txt
@@ -17,8 +17,11 @@ dataset: </dset1> and </dset1>
 0 differences found
 group  : </g1> and </g1>
 0 differences found
-group  : </g1/g2> and </g1/g2>
-0 differences found
+Not comparable: </g1/g2> is of type H5G_GROUP and </g1/g2> is of type H5G_UDLINK
 link   : </soft_dset1> and </soft_dset1>
 0 differences found
+--------------------------------
+Some objects are not comparable
+--------------------------------
+Use -c for a list of objects without details of differences.
 EXIT CODE: 1
diff --git a/tools/h5diff/testfiles/h5diff_517.txt b/tools/h5diff/testfiles/h5diff_517.txt
index 1b6e24f..91c69fb 100644
--- a/tools/h5diff/testfiles/h5diff_517.txt
+++ b/tools/h5diff/testfiles/h5diff_517.txt
@@ -10,6 +10,9 @@ group1   group2
 
 group  : </g1> and </g1>
 0 differences found
-group  : </g1/g2> and </g1/g2>
-0 differences found
+Not comparable: </g1/g2> is of type H5G_GROUP and </g1/g2> is of type H5G_UDLINK
+--------------------------------
+Some objects are not comparable
+--------------------------------
+Use -c for a list of objects without details of differences.
 EXIT CODE: 1
diff --git a/tools/h5diff/testfiles/non_comparables1.h5 b/tools/h5diff/testfiles/non_comparables1.h5
index 71b65c8..7dbb45d 100644
--- a/tools/h5diff/testfiles/non_comparables1.h5
+++ b/tools/h5diff/testfiles/non_comparables1.h5
diff --git a/tools/h5diff/testfiles/non_comparables2.h5 b/tools/h5diff/testfiles/non_comparables2.h5
index 188ceb9..a5e7014 100644
--- a/tools/h5diff/testfiles/non_comparables2.h5
+++ b/tools/h5diff/testfiles/non_comparables2.h5
diff --git a/tools/h5diff/testh5diff.sh b/tools/h5diff/testh5diff.sh
index 3eb3306..dfea6f7 100755
--- a/tools/h5diff/testh5diff.sh
+++ b/tools/h5diff/testh5diff.sh
@@ -156,6 +156,8 @@ $SRC_H5DIFF_TESTFILES/h5diff_208.txt
 $SRC_H5DIFF_TESTFILES/h5diff_220.txt
 $SRC_H5DIFF_TESTFILES/h5diff_221.txt
 $SRC_H5DIFF_TESTFILES/h5diff_222.txt
+$SRC_H5DIFF_TESTFILES/h5diff_223.txt
+$SRC_H5DIFF_TESTFILES/h5diff_224.txt
 $SRC_H5DIFF_TESTFILES/h5diff_21.txt
 $SRC_H5DIFF_TESTFILES/h5diff_22.txt
 $SRC_H5DIFF_TESTFILES/h5diff_23.txt
@@ -827,6 +829,12 @@ if test -n "$pmode" -a "$mydomainname" = hdfgroup.uiuc.edu; then
 else
     TOOLTEST h5diff_222.txt -c non_comparables1.h5 non_comparables2.h5
 fi    
+
+# non-comparable test for common objects (same name) with different object types
+# (HDFFV-7644)
+TOOLTEST h5diff_223.txt -c non_comparables1.h5 non_comparables2.h5 /diffobjtypes
+# swap files
+TOOLTEST h5diff_224.txt -c non_comparables2.h5 non_comparables1.h5 /diffobjtypes
     
 # ##############################################################################
 # # Links compare without --follow-symlinks nor --no-dangling-links
diff --git a/tools/lib/h5diff.c b/tools/lib/h5diff.c
index cef30dd..306f914 100644
--- a/tools/lib/h5diff.c
+++ b/tools/lib/h5diff.c
@@ -1121,6 +1121,8 @@ hsize_t diff_match(hid_t file1_id, const char *grp1, trav_info_t *info1,
     char * obj2_fullpath = NULL;
     h5trav_type_t objtype;
     diff_args_t argdata;
+    size_t idx1 = 0;
+    size_t idx2 = 0;
 
 
     /* 
@@ -1160,17 +1162,6 @@ hsize_t diff_match(hid_t file1_id, const char *grp1, trav_info_t *info1,
         }
     }
 
-    /* objects with the same name but different HDF5 types */
-    for( i = 0; i < table->nobjs; i++) 
-    {
-        if ( table->objs[i].flags[0] && table->objs[i].flags[1] )
-        {
-            if ( table->objs[i].type != table->objs[i].type )
-            {
-                options->contents = 0;
-            }
-        }
-    }
 
     /*-------------------------------------------------------------------------
     * do the diff for common objects
@@ -1205,8 +1196,18 @@ hsize_t diff_match(hid_t file1_id, const char *grp1, trav_info_t *info1,
             HDstrcpy(obj2_fullpath, grp2_path);
             HDstrcat(obj2_fullpath, table->objs[i].name);
 
+            /* get index to figure out type of the object in file1 */
+            while ( info1->paths[idx1].path && 
+                    (HDstrcmp (obj1_fullpath, info1->paths[idx1].path) != 0) )
+                idx1++;
+            /* get index to figure out type of the object in file2 */
+            while ( info2->paths[idx2].path &&
+                    (HDstrcmp (obj2_fullpath, info2->paths[idx2].path) != 0) )
+                idx2++;
+
             /* Set argdata to pass other args into diff() */
-            argdata.type = objtype;
+            argdata.type[0] = info1->paths[idx1].type;
+            argdata.type[1] = info2->paths[idx2].type;
             argdata.is_same_trgobj = table->objs[i].is_same_trgobj;
 
             options->cmn_objs = 1;
@@ -1242,7 +1243,8 @@ hsize_t diff_match(hid_t file1_id, const char *grp1, trav_info_t *info1,
                 HDstrcpy(args.name1, obj1_fullpath);
                 HDstrcpy(args.name2, obj2_fullpath);
                 args.options = *options;
-                args.argdata.type = objtype;
+                args.argdata.type[0] = info1->paths[idx1].type;
+                args.argdata.type[1] = info2->paths[idx2].type;
                 args.argdata.is_same_trgobj = table->objs[i].is_same_trgobj;
 
                 h5diffdebug2("busyTasks=%d\n", busyTasks);
@@ -1576,176 +1578,9 @@ hsize_t diff_compare(hid_t file1_id,
     obj1type = info1->paths[i].type;
     obj2type = info2->paths[j].type;
 
-    /*-----------------------------------------------------------------
-     * follow link option, compare with target object 
-    */
-    if (options->follow_links)
-    {
-        /* pass how to handle printing warning to linkinfo option */
-        if(print_warn(options))
-            linkinfo1.opt.msg_mode = linkinfo2.opt.msg_mode = 1;
-
-        /*------------------------------------------------------------
-         * Soft links
-         *------------------------------------------------------------*/
-
-        /*--------------------------
-         * if object1 soft link   */
-        if (obj1type == H5TRAV_TYPE_LINK)
-        {
-            /* get type of target object */
-            l_ret = H5tools_get_symlink_info(file1_id, obj1name, &linkinfo1, TRUE);
-            /* dangling link */
-            if (l_ret == 0)
-            {
-                if (options->no_dangle_links)
-                {
-                    /* gangling link is error */
-                    if(options->m_verbose)
-                        parallel_print("Warning: <%s> is a dangling link.\n", obj1name);
-                    options->err_stat = 1;
-                    goto out;
-                }
-                else
-                    is_dangle_link1 = 1;
-            }
-            /* fail */
-            else if(l_ret < 0)
-            {
-                options->err_stat = 1;
-                goto out;
-            }
-            else /* OK */
-            {
-                /* target type for diff() */
-                obj1type = linkinfo1.trg_type;
-            }
-        }
-        
-        /*-----------------------------
-         * if object2 is soft link   */
-        if (obj2type == H5TRAV_TYPE_LINK)
-        {
-            /* get type target object */
-            l_ret = H5tools_get_symlink_info(file2_id, obj2name, &linkinfo2, TRUE);
-            /* dangling link */
-            if (l_ret == 0)
-            {
-                if (options->no_dangle_links)
-                {
-                    /* gangling link is error */
-                    if(options->m_verbose)
-                        parallel_print("Warning: <%s> is a dangling link.\n", obj2name);
-                    options->err_stat = 1;
-                    goto out;
-                }
-                else
-                    is_dangle_link2=1;
-            }
-            /* fail */
-            else if(l_ret < 0)
-            {
-                options->err_stat = 1;
-                goto out;
-            }
-            else /* OK */
-            {
-                /* target type for diff() */
-                obj2type = linkinfo2.trg_type;
-            }
-        }
-
-        /*------------------------------------------------------------
-         * External links
-         *------------------------------------------------------------*/
-
-        /*--------------------------------
-         * if object1 is external link  */
-        if (obj1type == H5TRAV_TYPE_UDLINK)
-        {
-            /* get type and name of target object */
-            l_ret = H5tools_get_symlink_info(file1_id, obj1name, &linkinfo1, TRUE);
-            /* dangling link */
-            if (l_ret == 0)
-            {
-                if (options->no_dangle_links)
-                {
-                    /* gangling link is error */
-                    if(options->m_verbose)
-                        parallel_print("Warning: <%s> is a dangling link.\n", obj1name);
-                    options->err_stat = 1;
-                    goto out;
-                }
-                else
-                    is_dangle_link1 = 1;
-            }
-            /* fail */
-            else if(l_ret < 0)
-            {
-                options->err_stat = 1;
-                goto out;
-            }
-            else /* OK */
-            {
-                /* for external link */
-                if(linkinfo1.linfo.type == H5L_TYPE_EXTERNAL)
-                    obj1type = linkinfo1.trg_type;
-            }
-        }
-
-        /*--------------------------------
-         * if object2 is external link  */
-        if (obj2type == H5TRAV_TYPE_UDLINK)
-        {
-            /* get type and name of target object */
-            l_ret = H5tools_get_symlink_info(file2_id, obj2name, &linkinfo2, TRUE);
-            /* dangling link */
-            if (l_ret == 0)
-            {
-                if (options->no_dangle_links)
-                {
-                    /* gangling link is error */
-                    if(options->m_verbose)
-                        parallel_print("Warning: <%s> is a dangling link.\n", obj2name);
-                    options->err_stat = 1;
-                    goto out;
-                }
-                else
-                    is_dangle_link2 = 1;
-            }
-            /* fail */
-            else if(l_ret < 0)
-            {
-                options->err_stat = 1;
-                goto out;
-            }
-            else /* OK */
-            {
-                /* for external link */
-                if(linkinfo2.linfo.type == H5L_TYPE_EXTERNAL)
-                    obj2type = linkinfo2.trg_type;
-            }
-        }
-        /* found dangling link */
-        if (is_dangle_link1 || is_dangle_link2)
-            goto out;
-    } /* end of follow_links */
-    
-    /* objects are not the same type */
-    if (obj1type != obj2type)
-    {
-        if (options->m_verbose||options->m_list_not_cmp)
-        {
-            parallel_print("<%s> is of type %s and <%s> is of type %s\n",
-            obj1name, get_type(obj1type), 
-            obj2name, get_type(obj2type));
-        }
-        options->not_cmp=1;
-        goto out;
-    }
-
     /* Set argdata to pass other args into diff() */
-    argdata.type = obj1type;
+    argdata.type[0] = obj1type;
+    argdata.type[1] = obj2type;
     argdata.is_same_trgobj = 0;
 
     nfound = diff(file1_id, obj1name,
@@ -1806,7 +1641,8 @@ out:
  * Return: Number of differences found
  *
  * Programmer: Jonathan Kim
- *  - add following links feature (Feb 11,2010)
+ *  - Move follow symlinks code toward top. (March 2812)
+ *  - Add following symlinks feature (Feb 11,2010)
  *  - Change to use diff_args_t to pass the rest of args.
  *    Passing through it instead of individual args provides smoother
  *    extensibility through its members along with MPI code update for ph5diff
@@ -1834,6 +1670,7 @@ hsize_t diff(hid_t file1_id,
     int     is_dangle_link2 = 0;
     int     is_hard_link = 0;
     hsize_t nfound = 0;
+    h5trav_type_t object_type;
 
 
     /* to get link info */
@@ -1848,52 +1685,86 @@ hsize_t diff(hid_t file1_id,
     if(print_warn(options))
         linkinfo1.opt.msg_mode = linkinfo2.opt.msg_mode = 1;
 
-    /* 
-     * Get target object info for obj1 and obj2 and check dangling links.
-     * (for hard-linked-objects, because diff() only get the obj1's type, 
-     *  so obj2's type should be check here when diff() is called from 
-     *  diff_match() for same-named objects with dangling link only one side.)
-     */
-
-    /* target object1 - get type and name */
-    ret = H5tools_get_symlink_info(file1_id, path1, &linkinfo1, TRUE);
-    /* dangling link */
-    if (ret == 0)
+    /* for symbolic links, take care follow symlink and no dangling link 
+     * options */
+    if (argdata->type[0] == H5TRAV_TYPE_LINK || 
+        argdata->type[0] == H5TRAV_TYPE_UDLINK ||
+        argdata->type[1] == H5TRAV_TYPE_LINK || 
+        argdata->type[1] == H5TRAV_TYPE_UDLINK )
     {
-        if (options->no_dangle_links)
+        /* 
+         * check dangling links for path1 and path2
+         */
+
+        /* target object1 - get type and name */
+        ret = H5tools_get_symlink_info(file1_id, path1, &linkinfo1, TRUE);
+        /* dangling link */
+        if (ret == 0)
         {
-            /* gangling link is error */
-            if(options->m_verbose)
-                parallel_print("Warning: <%s> is a dangling link.\n", path1);
-            goto out;
+            if (options->no_dangle_links)
+            {
+                /* gangling link is error */
+                if(options->m_verbose)
+                    parallel_print("Warning: <%s> is a dangling link.\n", path1);
+                goto out;
+            }
+            else
+                is_dangle_link1 = 1;
         }
-        else
-            is_dangle_link1 = 1;
-    }
-    else if (ret < 0)
-        goto out;
+        else if (ret < 0)
+            goto out;
 
-    /* target object2 - get type and name */
-    ret = H5tools_get_symlink_info(file2_id, path2, &linkinfo2, TRUE);
-    /* dangling link */
-    if (ret == 0)
-    {
-        if (options->no_dangle_links)
+        /* target object2 - get type and name */
+        ret = H5tools_get_symlink_info(file2_id, path2, &linkinfo2, TRUE);
+        /* dangling link */
+        if (ret == 0)
         {
-            /* gangling link is error */
-            if(options->m_verbose)
-                parallel_print("Warning: <%s> is a dangling link.\n", path2);
+            if (options->no_dangle_links)
+            {
+                /* gangling link is error */
+                if(options->m_verbose)
+                    parallel_print("Warning: <%s> is a dangling link.\n", path2);
+                goto out;
+            }
+            else
+                is_dangle_link2 = 1;
+        }
+        else if (ret < 0)
             goto out;
+                    
+        /* found dangling link */
+        if (is_dangle_link1 || is_dangle_link2)
+            goto out2;
+
+        /* follow symbolic link option */
+        if (options->follow_links)
+        {
+            if (linkinfo1.linfo.type == H5L_TYPE_SOFT ||
+                linkinfo1.linfo.type == H5L_TYPE_EXTERNAL)
+                argdata->type[0] = linkinfo1.trg_type;
+
+            if (linkinfo2.linfo.type == H5L_TYPE_SOFT ||
+                linkinfo2.linfo.type == H5L_TYPE_EXTERNAL)
+                argdata->type[1] = linkinfo2.trg_type;
         }
-        else
-            is_dangle_link2 = 1;
     }
-    else if (ret < 0)
-        goto out;
-                
-    /* found dangling link */
-    if (is_dangle_link1 || is_dangle_link2)
+    /* if objects are not the same type */
+    if (argdata->type[0] != argdata->type[1])
+    {
+        if (options->m_verbose||options->m_list_not_cmp)
+        {
+            parallel_print("Not comparable: <%s> is of type %s and <%s> is of type %s\n",
+            path1, get_type(argdata->type[0]), 
+            path2, get_type(argdata->type[1]));
+        }
+        options->not_cmp=1;
+        /* TODO: will need to update non-comparable is different
+         * options->contents = 0;
+         */
         goto out2;
+    }
+    else /* now both object types are same */
+        object_type = argdata->type[0];
   
     /* 
      * If both points to the same target object, skip comparing details inside
@@ -1903,17 +1774,17 @@ hsize_t diff(hid_t file1_id,
      *
      * Perform this to match the outputs as bypassing.
      */
-     is_hard_link = (argdata->type == H5TRAV_TYPE_DATASET ||
-                     argdata->type == H5TRAV_TYPE_NAMED_DATATYPE ||
-                     argdata->type == H5TRAV_TYPE_GROUP);
-     if (options->follow_links || is_hard_link)
+     if (argdata->is_same_trgobj)
      {
-        if (argdata->is_same_trgobj)
+        is_hard_link = (object_type == H5TRAV_TYPE_DATASET ||
+                        object_type == H5TRAV_TYPE_NAMED_DATATYPE ||
+                        object_type == H5TRAV_TYPE_GROUP);
+        if (options->follow_links || is_hard_link)
         {
             /* print information is only verbose option is used */
             if(options->m_verbose || options->m_report)
             {
-                switch(argdata->type)
+                switch(object_type)
                 {
                 case H5TRAV_TYPE_DATASET:
                     do_print_objname("dataset", path1, path2, options);
@@ -1935,7 +1806,7 @@ hsize_t diff(hid_t file1_id,
                     break; 
                 default:
                     parallel_print("Comparison not supported: <%s> and <%s> are of type %s\n",
-                        path1, path2, get_type(argdata->type) );
+                        path1, path2, get_type(object_type) );
                     options->not_cmp = 1;
                     break;
                 } /* switch(type)*/
@@ -1943,11 +1814,12 @@ hsize_t diff(hid_t file1_id,
                 print_found(nfound);
             } /* if(options->m_verbose || options->m_report) */
 
+            /* exact same, so comparison is done */
             goto out2;
         }
     }
 
-    switch(argdata->type)
+    switch(object_type)
     {
        /*----------------------------------------------------------------------
         * H5TRAV_TYPE_DATASET
@@ -2064,30 +1936,6 @@ hsize_t diff(hid_t file1_id,
             if(print_objname(options, nfound))
                 do_print_objname("link", path1, path2, options);
 
-            if (options->follow_links)
-            {
-                /* objects are not the same type */
-                if (linkinfo1.trg_type != linkinfo2.trg_type)
-                {
-                    if (options->m_verbose||options->m_list_not_cmp)
-                    {
-                        parallel_print("<%s> is of type %s and <%s> is of type %s\n", path1, get_type(linkinfo1.trg_type), path2, get_type(linkinfo2.trg_type));
-                    }
-                    options->not_cmp=1;
-                    goto out;
-                }
-
-                /* Renew type in argdata to pass into diff(). 
-                 * For recursive call, argdata.is_same_trgobj is already
-                 * set from initial call, so don't reset here */
-                argdata->type = linkinfo1.trg_type;
-
-                /* call self to compare target object */
-                nfound += diff(file1_id, path1, 
-                               file2_id, path2, 
-                               options, argdata);
-            }
-
             /* always print the number of differences found in verbose mode */
             if(options->m_verbose)
                 print_found(nfound);
@@ -2121,28 +1969,6 @@ hsize_t diff(hid_t file1_id,
                 if(print_objname(options, nfound))
                     do_print_objname("external link", path1, path2, options);
 
-                if (options->follow_links)
-                {
-                    /* objects are not the same type */
-                    if (linkinfo1.trg_type != linkinfo2.trg_type)
-                    {
-                        if (options->m_verbose||options->m_list_not_cmp)
-                        {
-                            parallel_print("<%s> is of type %s and <%s> is of type %s\n", path1, get_type(linkinfo1.trg_type), path2, get_type(linkinfo2.trg_type));
-                        }
-                        options->not_cmp=1;
-                        goto out;
-                    }
-
-                    /* Renew type in argdata to pass into diff(). 
-                     * For recursive call, argdata.is_same_trgobj is already
-                     * set from initial call, so don't reset here */
-                    argdata->type = linkinfo1.trg_type;
-
-                    nfound = diff(file1_id, path1,  
-                                  file2_id, path2, 
-                                  options, argdata);
-                } 
             } /* end if */
             else 
             {
@@ -2172,7 +1998,7 @@ hsize_t diff(hid_t file1_id,
         default:
             if(options->m_verbose)
                 parallel_print("Comparison not supported: <%s> and <%s> are of type %s\n",
-                    path1, path2, get_type(argdata->type) );
+                    path1, path2, get_type(object_type) );
             options->not_cmp = 1;
             break;
      }
diff --git a/tools/lib/h5diff.h b/tools/lib/h5diff.h
index 1ff4402..6985b68 100644
--- a/tools/lib/h5diff.h
+++ b/tools/lib/h5diff.h
@@ -28,7 +28,7 @@
  * as it doesn't require interface change.
  *------------------------------------------------------------------------*/
 typedef struct {
-    h5trav_type_t   type;
+    h5trav_type_t   type[2];
     hbool_t is_same_trgobj;
 } diff_args_t;
 /*-------------------------------------------------------------------------