Repository: Unidata/netcdf-c (c)

Issue:
nccopy bug with user defined types
> The following issue was discovered and documented by our user community. Thanks!

* [Reporting a bug_missing functionality of the nccopy application - materials.zip](https://github.com/Unidata/netcdf-c/files/6071805/Reporting.a.bug_missing.functionality.of.the.nccopy.application.-.materials.zip)

Attn: @DennisHeimbigner 

----

1. Issue
Under certain particular circumstances nccopy fails to determine the type of attributes when they have a user defined type.



2. Informal description
Here is how nccopy fails in this regard:
-	when attempting to copy the schema of a variable, nccopy will also attempt to copy its attributes
-	for each attribute with a user defined type this type needs to be determined at this step
-	for example, _FillValue attributes for enumerated type variables obviously have a user defined type
-	the current implementation of nccopy (4.7.4) fails to determine the user define type (in some cases) because of the way it searches for the data type, which goes like this:
    o	first, the type is searched for in the parent group of the variable
    o	if it is found there, then nccopy works just fine
    o	else the search continues "recursively" in the subgroups of the variable's parent group; this is where a first issue is as nccopy should look in the ancestor groups, until reaching the root group; the copying of some of the enumerated type variables fails with a "Not a valid data type or _FillValue type mismatch" error because of this
    o	for other enumerated type variables we see a Segmentation fault instead
    o	this second issue is because the recursive search mentioned above is probably not what the implementer really intended; instead of doing a depth-first search, it gets stuck in an infinite recursive call (from the variable's parent group back to itself); this causes a stack overflow after enough recursive calls; apparently on Linux systems there is no detection for stack overflow, so this eventually results into a segmentation fault (which weíre seeing for all enumerated type variables in a group which does not itself contain the enumerated type definition, but has subgroups in which to try to recurse, and fails to do that because of the reason described above).



3. How to reproduce the issue
create_and_copy_all_examples.sh will call:
- create_enum_variable_with_type_defined_in_ancestor_group_with_no_subgroups.py
- create_enum_variable_with_type_defined_in_ancestor_group_with_subgroups.py
- create_enum_variable_with_type_defined_in_same_group.py.

These scripts will create the following minimal example products:
- type_defined_in_ancestor_group_with_no_subgroups.nc (the type is defined in the root group, while the variable is defined in a separate group, but this group does not have subgroups)
- type_defined_in_ancestor_group_with_subgroups.nc (the type is defined in the root group, while the variable is defined in a separate group and this group has subgroups)
- type_defined_in_same_group.nc (the type and the variable are defined in the same group)
respectively.

create_and_copy_all_examples.sh then attempts to nccopy these three products with the following results:
- for type_defined_in_ancestor_group_with_no_subgroups.nc nccopy fails with the following error:
NetCDF: Not a valid data type or _FillValue type mismatch
Location: file /tmp/build/80754af9/libnetcdf_1582139698333/work/ncdump/nccopy.c; line 1326
(also producing the partial copy product: type_defined_in_ancestor_group_with_no_subgroups_copy.nc)
- for type_defined_in_ancestor_group_with_subgroups.nc nccopy fails with the following error:
Segmentation fault (core dumped)
(also producing the corrupted product: type_defined_in_ancestor_group_with_subgroups_copy.nc)
- for type_defined_in_same_group.nc nccopy successfully copies the product (see the copy product: type_defined_in_same_group_copy.nc).



4. How to trace and maybe solve the issue
Source code    : https://github.com/Unidata/netcdf-c/tree/v4.7.4
Build like this: https://www.unidata.ucar.edu/software/netcdf/docs/getting_and_building_netcdf.html#netCDF-CMake

Source files involved:
- https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c
- https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c

Reversed stack trace:
- copy: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L2369
- copy_schema: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L2051
- copy_vars: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L1481
- copy_var: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L1460
- copy_atts: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L1414
- nc_copy_att: https://github.com/Unidata/netcdf-c/blob/v4.7.4/ncdump/nccopy.c#L1368
- NC_copy_att: https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L709
- NC_find_equal_type: https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L588
- NC_rec_find_nc_type: https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L259
- the problematic part: https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L199

The search for the type should recurse going up the group hierarchy, not down (or in both directions). In the current implementation, the type is looked for in the subgroups of the variable's parent group. But it should be looked for in the supergroups too (or even excusively in the supergroups).
This is the cause of the "Not a valid data type or _FillValue type mismatch" error when the user defined type is defined in a supergroup of the variable's parent group. We follow this approach when we reuse a type in multiple subgroups (avoiding repeating the same definition).
In order to go up the group hierarchy, the nc_inq_grps calls should be replaced by calls to a function determining the ancestor groups on the path to the root, here https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L200 and here https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L206 and the recursive call to NC_rec_find_nc_type should be removed (i.e. https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L213).
In a more efficient approach, just the parent group could be determined and then the other ancestors could be determined by the recursive call to NC_rec_find_nc_type. This should deal with the issue.

Additionally (independent of the main issue regarding the at least restrictive direction of search in the group hierarchy), in the current implementation the recursive call enters an infinite loop because:
- the first argument stays the same (i.e. the input group/file ID); see https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L213
- the recursive search is done in subgroups of this input group/file; see https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L200 and https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L206.
This probably causes a stack overflow (which sometimes causes a segmentation fault on Linux systems).
This second issue can be fixed by either:
- solution 1: modifying the first argument in sync with the recursive step (i.e. go down in the input group hierarchy with this first argument too)
e.g. replace https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L213
with ret = NC_rec_find_nc_type(ids[i], tid1, ids[i], tid2);
- solution 2: doing the search in the subgroups of the output group/file
e.g replace https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L200
with if ((ret = nc_inq_grps(ncid2, &nids, NULL)))
and 
replace https://github.com/Unidata/netcdf-c/blob/v4.7.4/libdispatch/dcopy.c#L206
with if ((ret = nc_inq_grps(ncid2, &nids, ids))).
Solution 2 will only work if the input and output files have identical group IDs (it needs to be confirmed if that is the case).
These fixes will not solve the first issue (regarding the direction of the search). They'll just avoid the stack overflow.


Pull request:
Regularize the scoping of types
* Fixes #1956
re: Github issue https://github.com/Unidata/netcdf-c/issues/1956

The function NC_compare_nc_types in libdispatch/dcopy.c uses an incorrect algorithm to search for types. The core of this is the function NC_rec_find_nc_type in libdispatch/dcopy.c. Currently it searchs the current group and its subtree.

Additionally, the function NC4_inq_typeid in libsrc4/nc4internal.c has been extended to handle fully qualified names. It was originally designed to do this, but for some reason never completed.

The NC_rec_find_nc_type algorithm has been altered to match the algorithm used by NC4_inq_typeid. It operates as follows.

Given a file F, group G and a type T. It searches file F2, group G2, for another type T2 that is equivalent to T.

The search order is as follows.
1. Search G2 for a type T2 equivalent to T.
2. Search upwards in the ancestor groups of G2 for a type T2 equivalent to T.
3. Search the complete group tree of F2 in pre-order, breadth-first order to locate T2 equivalent to T.

Also add a test case to validate algorithm: ncdump/test_scope.sh.

Note, this change may cause compatibility problems, though it is unlikely because two different equivalent type declarations in one dataset is unlikely.

Misc. Other Changes:
* Add a helper test program -- _ncdump/printfqn_ to print out the FQN for a typeid taken from the test_scope generated .nc files.


Patch:
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 2cc50fb14..79c0c2a66 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -4,8 +4,10 @@ Release Notes       {#RELEASE_NOTES}
 \brief Release notes file for the netcdf-c package.
 
 This file contains a high-level description of this package's evolution. Releases are in reverse chronological order (most recent first). Note that, as of netcdf 4.2, the `netcdf-c++` and `netcdf-fortran` libraries have been separated into their own libraries.
+
 ## 4.8.1 - TBD
 
+* [Bug Fixes] The netcdf-c library was incorrectly determining the scope of types referred to by nc_inq_type_equal. See [Github #1959](https://github.com/Unidata/netcdf-c/pull/1959) for more information.
 * [Bug Fix] Fix bug in use of XGetopt when building under Mingw. See [Github #2009](https://github.com/Unidata/netcdf-c/issues/2009).
 * [Enhancement] Improve the error reporting when attempting to use a filter for which no implementation can be found in HDF5_PLUGIN_PATH. See [Github #2000](https://github.com/Unidata/netcdf-c/pull/2000) for more information.
 * [Bug Fix] Fix `make distcheck` issue in `nczarr_test/` directory. See [Github #2007](https://github.com/Unidata/netcdf-c/issues/2007).
diff --git a/include/ncconfigure.h b/include/ncconfigure.h
index 32fd1cc9b..2b4375ea5 100644
--- a/include/ncconfigure.h
+++ b/include/ncconfigure.h
@@ -16,6 +16,9 @@
 #ifdef HAVE_STDIO_H
 #include <stdio.h>
 #endif
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
 
 /*
 This is included in bottom
diff --git a/include/ncpathmgr.h b/include/ncpathmgr.h
index 631327b7e..e1b33b8fa 100644
--- a/include/ncpathmgr.h
+++ b/include/ncpathmgr.h
@@ -102,6 +102,9 @@ EXTERNL int NChasdriveletter(const char* path);
 /* Canonicalize and make absolute by prefixing the current working directory */
 EXTERNL char* NCpathabsolute(const char* name);
 
+/* Check if this path appears to start with a windows drive letter */
+EXTERNL int NChasdriveletter(const char* path);
+
 /* Convert from the local coding (e.g. ANSI) to utf-8;
    note that this can produce unexpected results for Windows
    because it first converts to wide character and then to utf8. */
diff --git a/libdispatch/dcopy.c b/libdispatch/dcopy.c
index 04c748f7b..8a73f9d82 100644
--- a/libdispatch/dcopy.c
+++ b/libdispatch/dcopy.c
@@ -10,8 +10,13 @@
 #include "config.h"
 #include "ncdispatch.h"
 #include "nc_logging.h"
+#include "nclist.h"
 
 #ifdef USE_NETCDF4
+
+static int searchgroup(int ncid1, int tid1, int grp, int* tid2);
+static int searchgrouptree(int ncid1, int tid1, int grp, int* tid2);
+
 /**
  * @internal Compare two netcdf types for equality. Must have the
  * ncids as well, to find user-defined types.
@@ -27,8 +32,7 @@
  * @author Ed Hartnett
 */
 static int
-NC_compare_nc_types(int ncid1, int typeid1, int ncid2, int typeid2,
-		    int *equalp)
+NC_compare_nc_types(int ncid1, int typeid1, int ncid2, int typeid2, int *equalp)
 {
    int ret = NC_NOERR;
 
@@ -152,8 +156,15 @@ NC_compare_nc_types(int ncid1, int typeid1, int ncid2, int typeid2,
 }
 
 /**
- * @internal Recursively hunt for a netCDF type id. (Code from
- * nc4internal.c); Return matching typeid or 0 if not found.
+ * @internal Recursively hunt for a netCDF type id, tid2, that is "equal" to tid1.
+ * Question is: what search order do we use? Ncgen uses root group tree in pre-order.
+ * But NC4_inq_typeid uses these rules:
+ * 1. ncid2
+ * 2. parents of ncid2 (up the tree to root)
+ * 3. root group tree in pre-order.
+ * We will leave ncgen for another day and use the nc_inq_typeid rule.
+ *
+ * Return matching typeid or 0 if not found.
  *
  * @param ncid1 File ID.
  * @param tid1 Type ID.
@@ -161,68 +172,35 @@ NC_compare_nc_types(int ncid1, int typeid1, int ncid2, int typeid2,
  * @param tid2 Pointer that gets type ID of equal type.
  *
  * @return ::NC_NOERR No error.
- * @author Ed Hartnett
+ * @author Ed Hartnett, Dennis Heimbigner
 */
 static int
 NC_rec_find_nc_type(int ncid1, nc_type tid1, int ncid2, nc_type* tid2)
 {
-   int i,ret = NC_NOERR;
-   int nids;
-   int* ids = NULL;
-
-   /* Get all types in grp ncid2 */
-   if(tid2)
-      *tid2 = 0;
-   if ((ret = nc_inq_typeids(ncid2, &nids, NULL)))
-      return ret;
-   if (nids)
-   {
-      if (!(ids = (int *)malloc((size_t)nids * sizeof(int))))
-	 return NC_ENOMEM;
-      if ((ret = nc_inq_typeids(ncid2, &nids, ids)))
-	 return ret;
-      for(i = 0; i < nids; i++)
-      {
-	 int equal = 0;
-	 if ((ret = NC_compare_nc_types(ncid1, tid1, ncid2, ids[i], &equal)))
-	    return ret;
-	 if(equal)
-	 {
-	    if(tid2)
-	       *tid2 = ids[i];
-	    free(ids);
-	    return NC_NOERR;
-	 }
-      }
-      free(ids);
+    int ret = NC_NOERR;
+    int parent;
+
+    if((ret = searchgroup(ncid1,tid1,ncid2,tid2)))
+        goto done;
+    if(*tid2 != 0)
+        goto done; /* found */
+
+   /* Look in the parents of ncid2 upto the root */
+   switch (ret = nc_inq_grp_parent(ncid2,&parent)) {
+   case NC_NOERR:
+	/* Recurse up using parent grp */
+        ret = NC_rec_find_nc_type(ncid1, tid1, parent, tid2);
+	break;
+   case NC_ENOGRP:
+	/* do the breadth-first pre-order search of the whole tree */
+	/* ncid2 should be root group */
+	ret = searchgrouptree(ncid1,tid1,ncid2,tid2);
+	break;
+   default: break;
    }
 
-   /* recurse */
-   if ((ret = nc_inq_grps(ncid1, &nids, NULL)))
-      return ret;
-   if (nids)
-   {
-      if (!(ids = (int *)malloc((size_t)nids * sizeof(int))))
-	 return NC_ENOMEM;
-      if ((ret = nc_inq_grps(ncid1, &nids, ids)))
-      {
-	 free(ids);
-	 return ret;
-      }
-      for (i = 0; i < nids; i++)
-      {
-	 ret = NC_rec_find_nc_type(ncid1, tid1, ids[i], tid2);
-	 if (ret && ret != NC_EBADTYPE)
-	    break;
-	 if (tid2 && *tid2 != 0) /* found */
-	 {
-	    free(ids);
-	    return NC_NOERR;
-	 }
-      }
-      free(ids);
-   }
-   return NC_EBADTYPE; /* not found */
+done:
+    return ret;
 }
 
 /**
@@ -711,3 +689,92 @@ nc_copy_att(int ncid_in, int varid_in, const char *name,
 
    return NC_NOERR;
 }
+
+#ifdef USE_NETCDF4
+
+/* Helper function for NC_rec_find_nc_type();
+   search a specified group for matching type.
+*/
+static int
+searchgroup(int ncid1, int tid1, int grp, int* tid2)
+{
+    int i,ret = NC_NOERR;
+    int nids;
+    int* ids = NULL;
+
+    /* Get all types in grp */
+    if(tid2)
+	*tid2 = 0;
+    if ((ret = nc_inq_typeids(grp, &nids, NULL)))
+	goto done;
+    if (nids)
+    {
+	if (!(ids = (int *)malloc((size_t)nids * sizeof(int))))
+	    {ret = NC_ENOMEM; goto done;}
+	if ((ret = nc_inq_typeids(grp, &nids, ids)))
+	    goto done;
+	for(i = 0; i < nids; i++)
+        {
+	    int equal = 0;
+	    if ((ret = NC_compare_nc_types(ncid1, tid1, grp, ids[i], &equal)))
+	        goto done;
+	    if(equal)
+	    {
+		if(tid2)
+		    *tid2 = ids[i];
+		goto done;
+	    }
+	}
+    }
+
+done:
+    nullfree(ids);
+    return ret;
+}
+
+/* Helper function for NC_rec_find_nc_type();
+   search a tree of groups for a matching type
+   using a breadth first queue
+*/
+static int
+searchgrouptree(int ncid1, int tid1, int grp, int* tid2)
+{
+    int i,ret = NC_NOERR;
+    int nids;
+    int* ids = NULL;
+    NClist* queue = nclistnew();
+    int gid;
+    uintptr_t id;
+
+    id = grp;
+    nclistpush(queue,(void*)id); /* prime the queue */
+    while(nclistlength(queue) > 0) {
+        id = (uintptr_t)nclistremove(queue,0);
+	gid  = (int)id;
+        if((ret = searchgroup(ncid1,tid1,gid,tid2)))
+            goto done;
+        if(*tid2 != 0)
+            goto done; /*we found it*/
+	/* Get subgroups of gid and push onto front of the queue (for breadth first) */
+        if((ret = nc_inq_grps(gid,&nids,NULL)))
+            goto done;
+        if (!(ids = (int *)malloc((size_t)nids * sizeof(int))))
+	    {ret = NC_ENOMEM; goto done;}
+        if ((ret = nc_inq_grps(gid, &nids, ids)))
+            goto done;
+	/* push onto the end of the queue */
+        for(i=0;i<nids;i++) {
+	    id = ids[i];
+	    nclistpush(queue,(void*)id);
+	}
+    }
+    /* Not found */
+    ret = NC_EBADTYPE;
+
+done:
+    nclistfree(queue);
+    nullfree(ids);
+    return ret;
+}
+
+#endif
diff --git a/libdispatch/dinfermodel.c b/libdispatch/dinfermodel.c
index a92c7a80a..7bfc4fd46 100644
--- a/libdispatch/dinfermodel.c
+++ b/libdispatch/dinfermodel.c
@@ -44,7 +44,7 @@ struct MagicFile {
     struct NCURI* uri;
     int omode;
     NCmodel* model;
-    long long filelen;
+    size64_t filelen;
     int use_parallel;
     void* parameters; /* !NULL if inmemory && !diskless */
     FILE* fp;
diff --git a/libsrc4/nc4type.c b/libsrc4/nc4type.c
index 12deea9d4..4e3592f18 100644
--- a/libsrc4/nc4type.c
+++ b/libsrc4/nc4type.c
@@ -554,8 +554,8 @@ NC4_inq_typeid(int ncid, const char *name, nc_type *typeidp)
     NC_GRP_INFO_T *grptwo;
     NC_FILE_INFO_T *h5;
     NC_TYPE_INFO_T *type = NULL;
-    char *norm_name;
-    int i, retval;
+    char *norm_name = NULL;
+    int i, retval = NC_NOERR;
 
     /* Handle atomic types. */
     for (i = 0; i < NUM_ATOMIC_TYPES; i++)
@@ -563,27 +563,47 @@ NC4_inq_typeid(int ncid, const char *name, nc_type *typeidp)
         {
             if (typeidp)
                 *typeidp = i;
-            return NC_NOERR;
+            goto done;
         }
 
     /* Find info for this file and group, and set pointer to each. */
     if ((retval = nc4_find_grp_h5(ncid, &grp, &h5)))
-        return retval;
+        goto done;
     assert(h5 && grp);
 
     /* If the first char is a /, this is a fully-qualified
      * name. Otherwise, this had better be a local name (i.e. no / in
      * the middle). */
     if (name[0] != '/' && strstr(name, "/"))
-        return NC_EINVAL;
+        {retval = NC_EINVAL; goto done;}
 
     /* Normalize name. */
     if (!(norm_name = (char*)malloc(strlen(name) + 1)))
-        return NC_ENOMEM;
-    if ((retval = nc4_normalize_name(name, norm_name))) {
-        free(norm_name);
-        return retval;
+        {retval = NC_ENOMEM; goto done;}
+    if ((retval = nc4_normalize_name(name, norm_name)))
+	goto done;
+
+    /* If this is a fqn, then walk the sequence of parent groups to the last group
+       and see if that group has a type of the right name */
+    if(name[0] == '/') { /* FQN */
+	int rootncid = (grp->nc4_info->root_grp->hdr.id | grp->nc4_info->controller->ext_ncid);
+	int parent = 0;
+	char* lastname = strrchr(norm_name,'/'); /* break off the last segment: the type name */
+	if(lastname == norm_name)
+	    {retval = NC_EINVAL; goto done;}
+	*lastname++ = '\0'; /* break off the lastsegment */
+	if((retval = NC4_inq_grp_full_ncid(rootncid,norm_name,&parent))) 
+	    goto done;
+	/* Get parent info */
+	if((retval=nc4_find_nc4_grp(parent,&grp)))
+	    goto done;
+	/* See if type exists in this group */
+        type = (NC_TYPE_INFO_T*)ncindexlookup(grp->type,lastname);
+	if(type == NULL) 	
+	    {retval = NC_EBADTYPE; goto done;}
+	goto done;
     }
+
     /* Is the type in this group? If not, search parents. */
     for (grptwo = grp; grptwo; grptwo = grptwo->parent) {
         type = (NC_TYPE_INFO_T*)ncindexlookup(grptwo->type,norm_name);
@@ -602,13 +622,13 @@ NC4_inq_typeid(int ncid, const char *name, nc_type *typeidp)
             if (typeidp)
                 *typeidp = type->hdr.id;
 
-    free(norm_name);
-
     /* OK, I give up already! */
     if (!type)
-        return NC_EBADTYPE;
+        {retval = NC_EBADTYPE; goto done;}
 
-    return NC_NOERR;
+done:
+    nullfree(norm_name);
+    return retval;
 }
 
 /**
diff --git a/ncdump/CMakeLists.txt b/ncdump/CMakeLists.txt
index 462231bb3..b8cfdc5bf 100644
--- a/ncdump/CMakeLists.txt
+++ b/ncdump/CMakeLists.txt
@@ -13,6 +13,7 @@ SET(ncdump_FILES ncdump.c vardata.c dumplib.c indent.c nctime0.c utils.c nciter.
 SET(nccopy_FILES nccopy.c nciter.c chunkspec.c utils.c dimmap.c list.c)
 SET(ocprint_FILES ocprint.c)
 SET(ncvalidator_FILES ncvalidator.c)
+SET(printfqn_FILES printfqn.c)
 
 IF(USE_X_GETOPT)
   SET(ncdump_FILES ${ncdump_FILES} XGetopt.c)
@@ -27,6 +28,7 @@ ADD_EXECUTABLE(ncvalidator ${ncvalidator_FILES})
 
 IF(USE_HDF5)
   ADD_EXECUTABLE(nc4print nc4print.c nc4printer.c)
+  ADD_EXECUTABLE(printfqn  ${printfqn_FILES})
 ENDIF(USE_HDF5)
 
 IF(ENABLE_DAP)
@@ -39,6 +41,7 @@ TARGET_LINK_LIBRARIES(ncvalidator netcdf ${ALL_TLL_LIBS})
 
 IF(USE_HDF5)
   TARGET_LINK_LIBRARIES(nc4print netcdf ${ALL_TLL_LIBS})
+  TARGET_LINK_LIBRARIES(printfqn netcdf ${ALL_TLL_LIBS})
 ENDIF(USE_HDF5)
 
 IF(ENABLE_DAP)
@@ -81,6 +84,15 @@ IF(MSVC)
       ${CMAKE_CURRENT_BINARY_DIR})
     SET_TARGET_PROPERTIES(ncvalidator PROPERTIES RUNTIME_OUTPUT_DIRECTORY_RELEASE
       ${CMAKE_CURRENT_BINARY_DIR})
+
+    SET_TARGET_PROPERTIES(printfqn PROPERTIES RUNTIME_OUTPUT_DIRECTORY
+      ${CMAKE_CURRENT_BINARY_DIR})
+    SET_TARGET_PROPERTIES(printfqn PROPERTIES RUNTIME_OUTPUT_DIRECTORY_DEBUG
+      ${CMAKE_CURRENT_BINARY_DIR})
+    SET_TARGET_PROPERTIES(printfqn PROPERTIES RUNTIME_OUTPUT_DIRECTORY_RELEASE
+      ${CMAKE_CURRENT_BINARY_DIR})
+
+
   ENDIF(USE_HDF5)
 
   IF(ENABLE_DAP)
@@ -315,8 +327,14 @@ IF(ENABLE_TESTS)
   add_sh_test(ncdump test_keywords)
   ENDIF()
 
+
+  IF(USE_HDF5)
+  add_sh_test(ncdump test_scope)
+  ENDIF()
+
   add_sh_test(ncdump test_rcmerge)
 
+
 ENDIF(ENABLE_TESTS)
 
 #IF(MSVC)
diff --git a/ncdump/Makefile.am b/ncdump/Makefile.am
index 017a00d99..1eea46a1a 100644
--- a/ncdump/Makefile.am
+++ b/ncdump/Makefile.am
@@ -46,6 +46,13 @@ if USE_HDF5
 bin_PROGRAMS += nc4print
 noinst_PROGRAMS += nc4print
 nc4print_SOURCES = nc4print.c nc4printer.c
+
+# Create a helper program for tst_scope.sh
+# Program prints out the fqn of the type of
+# a specified variable in the .nc file.
+noinst_PROGRAMS += printfqn
+printfqn_SOURCES = printfqn.c
+
 endif
 
 # Conditionally build the ocprint program, but do not install
@@ -103,7 +110,7 @@ TESTS += tst_fileinfo.sh tst_hdf5_offset.sh tst_inttags4.sh		\
 tst_netcdf4.sh tst_fillbug.sh tst_netcdf4_4.sh tst_nccopy4.sh		\
 tst_nccopy5.sh tst_grp_spec.sh tst_mud.sh tst_h_scalar.sh tst_formatx4.sh		\
 run_utf8_nc4_tests.sh run_back_comp_tests.sh run_ncgen_nc4_tests.sh	\
-tst_ncgen4.sh
+tst_ncgen4.sh test_scope.sh
 
 # Record interscript dependencies so parallel builds work.
 tst_nccopy4.log: run_ncgen_tests.log tst_output.log tst_ncgen4.log	\
@@ -166,10 +173,10 @@ ref_provenance_v1.nc ref_tst_radix.cdl tst_radix.cdl test_radix.sh	\
 ref_nccopy_w.cdl tst_nccopy_w3.sh tst_nccopy_w4.sh			\
 ref_no_ncproperty.nc test_unicode_directory.sh				\
 ref_roman_szip_simple.cdl ref_roman_szip_unlim.cdl ref_tst_perdimspecs.cdl \
-test_keywords.sh ref_keyword1.cdl ref_keyword2.cdl                      \
-ref_keyword3.cdl ref_keyword4.cdl                                       \
-ref_tst_nofilters.cdl test_unicode_path.sh test_rcmerge.sh              \
-ref_rcmerge1.txt ref_rcmerge2.txt ref_rcmerge3.txt
+test_keywords.sh ref_keyword1.cdl ref_keyword2.cdl ref_keyword3.cdl ref_keyword4.cdl \
+ref_tst_nofilters.cdl test_scope.sh type_group_only.cdl type_ancestor_only.cdl \
+type_ancestor_subgroup.cdl type_preorder.cdl test_unicode_path.sh \
+test_rcmerge.sh ref_rcmerge1.txt ref_rcmerge2.txt ref_rcmerge3.txt
 
 # The L512.bin file is file containing exactly 512 bytes each of value 0.
 # It is used for creating hdf5 files with varying offsets for testing.
@@ -206,9 +213,11 @@ ctest64.c nccopy3_subset_out.nc camrun.c tst_ncf213.cdl tst_ncf213.nc	\
 tst_radix.nc tmp_radix.cdl ctest_small_3.c ctest_small_4.c		\
 ctest_special_atts_4.c tst_roman_szip_simple.cdl			\
 tst_roman_szip_unlim.cdl tst_perdimpspecs.nc tmppds.*                   \
-keyword1.nc keyword2.nc keyword3.nc keyword4.nc                         \
-tmp_keyword1.cdl tmp_keyword2.cdl tmp_keyword3.cdl tmp_keyword4.cdl
+keyword1.nc keyword2.nc keyword3.nc keyword4.nc \
+tmp_keyword1.cdl tmp_keyword2.cdl tmp_keyword3.cdl tmp_keyword4.cdl       \
+type_*.nc copy_type_*.cdl
 
 # Remove directories
 clean-local:
 	rm -fr rcmergedir
+
diff --git a/ncdump/printfqn.c b/ncdump/printfqn.c
new file mode 100644
index 000000000..2392c460c
--- /dev/null
+++ b/ncdump/printfqn.c
@@ -0,0 +1,143 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <netcdf.h>
+
+#define CHECK(err) {if(err) report(err,__LINE__);}
+
+static void
+report(int err, int lineno)
+{
+    fprintf(stderr,"Error: %d: %s\n", lineno, nc_strerror(err));
+    exit(1);
+}
+
+void
+usage(void)
+{
+    fprintf(stderr,"usage: printfqn <filename> <varname>\n");
+    exit(0);
+}
+
+int
+get_type_parent(int ncid, int tid, int* parentp)
+{
+    int stat = NC_NOERR;
+    int i;
+    int nids;
+    int ids[4096];
+
+    /* Does this group have the type we are searching for? */
+    if((stat=nc_inq_typeids(ncid,&nids,ids))) goto done;
+    assert(nids < 4096);
+
+    /* Search for this typeid */
+    for(i=0;i<nids;i++) {
+	if(ids[i] == tid) {
+	    if(parentp) *parentp = ncid;
+	    goto done;
+	}
+    }
+
+    /* Else Search subgroups. */
+    if((stat=nc_inq_grps(ncid,&nids,ids))) goto done;
+    assert(nids < 4096);
+
+    /* Recurse on each subgroup */
+    for(i=0;i<nids;i++) {
+	switch (stat = get_type_parent(ids[i],tid,parentp)) {
+	case NC_EBADTYPE: break; /* not found; keep looking */
+	case NC_NOERR: goto done; /* found it */
+	default: goto done; /* some other error */
+	}
+    }
+    stat = NC_EBADTYPE; /* Not found */
+
+done:
+    return stat;
+
+}
+
+int
+get_variable_info(int ncid, const char* name, int* gidp, int* vidp)
+{
+    int stat = NC_NOERR;
+    int i;
+    int nids;
+    int ids[4096];
+    char varname[NC_MAX_NAME];
+
+    /* Assume only one occurrence of the variable in dataset */
+
+    /* Does this group have the variable we are searching for? */
+    if((stat=nc_inq_varids(ncid,&nids,ids))) goto done;
+    assert(nids < 4096);
+
+    /* Search for this variable name */
+    for(i=0;i<nids;i++) {
+	if((stat = nc_inq_varname(ncid,ids[i],varname))) goto done;
+	if(strcmp(name,varname)==0) {
+	    if(gidp) *gidp = ncid;
+	    if(vidp) *vidp = ids[i];
+	    goto done;
+	}
+    }
+
+    /* Else Search subgroups. */
+    if((stat=nc_inq_grps(ncid,&nids,ids))) goto done;
+    assert(nids < 4096);
+
+    /* Recurse on each subgroup */
+    for(i=0;i<nids;i++) {
+	switch (stat = get_variable_info(ids[i],name,gidp,vidp)) {
+	case NC_ENOTVAR: break; /* not found; keep looking */
+	case NC_NOERR: goto done; /* found it */
+	default: goto done; /* some other error */
+	}
+    }
+    stat = NC_ENOTVAR; /* Not found */
+
+done:
+    return stat;
+}
+
+int
+main(int argc, char** argv)
+{
+    int ncid, varid, gid, tid;
+    const char* filename = NULL;
+    char varname[NC_MAX_NAME];
+    size_t fqnlen, namelen;
+    char fqn[4096];
+    char name[NC_MAX_NAME];
+    
+    if(argc < 3) usage();
+
+    filename = argv[1];
+    strcpy(varname,argv[2]);
+
+    CHECK(nc_open(filename,NC_NETCDF4,&ncid));
+
+    /* Locate the parent group for the variable */
+    CHECK(get_variable_info(ncid,varname,&gid,&varid));
+
+    /* Get the type id of the variable */
+    CHECK(nc_inq_vartype(gid,varid,&tid));
+    /* Get the type name */
+    CHECK(nc_inq_type(ncid,tid,name,&namelen));
+
+    /* Get the containing group id for the type */
+    CHECK(get_type_parent(ncid,tid,&gid));
+
+    /* Get the FQN name for the containing type */
+    CHECK(nc_inq_grpname_full(gid,&fqnlen,fqn));
+    assert(fqnlen < sizeof(fqn));
+
+    if(strcmp(fqn,"/")==0) fqn[0] = '\0';
+
+    /* report result  with no newline */
+    printf("|%s/%s|",fqn,name);
+
+    return 0;
+}
diff --git a/ncdump/type_ancestor_only.cdl b/ncdump/type_ancestor_only.cdl
new file mode 100644
index 000000000..51e64711d
--- /dev/null
+++ b/ncdump/type_ancestor_only.cdl
@@ -0,0 +1,21 @@
+netcdf type_ancestor_only {
+types:
+  ubyte enum test_enum_type {OPTION1 = 0, OPTION2 = 1, OPTION3 = 2} ;
+
+group: test_group {
+  variables:
+  	test_enum_type test_variable ;
+  		test_enum_type test_variable:_FillValue = OPTION1 ;
+
+  group: test_subgroup1 {
+
+      group: test_subsubgroup {
+      } // group test_subsubgroup
+
+   } // group test_subgroup1
+
+    group: test_subgroup2 {
+    } // group test_subgroup2
+
+  } // group test_group
+}
diff --git a/ncdump/type_ancestor_subgroup.cdl b/ncdump/type_ancestor_subgroup.cdl
new file mode 100644
index 000000000..b213d5bea
--- /dev/null
+++ b/ncdump/type_ancestor_subgroup.cdl
@@ -0,0 +1,15 @@
+netcdf type_ancestor_subgroup {
+types:
+  ubyte enum test_enum_type {OPTION1 = 0, OPTION2 = 1, OPTION3 = 2} ;
+
+group: test_group {
+  variables:
+  	test_enum_type test_variable ;
+  		test_enum_type test_variable:_FillValue = OPTION1 ;
+  group: sub_group {
+      types:
+      ubyte enum test_enum_type {OPTION1 = 0, OPTION2 = 1, OPTION3 = 2} ;
+  } // group sub_group
+
+  } // group test_group
+}
diff --git a/ncdump/type_group_only.cdl b/ncdump/type_group_only.cdl
new file mode 100644
index 000000000..b19f38cfc
--- /dev/null
+++ b/ncdump/type_group_only.cdl
@@ -0,0 +1,10 @@
+netcdf type_group_only {
+
+group: test_group {
+  types:
+    ubyte enum test_enum_type {OPTION1 = 0, OPTION2 = 1, OPTION3 = 2} ;
+  variables:
+  	test_enum_type test_variable ;
+  		test_enum_type test_variable:_FillValue = OPTION1 ;
+  } // group test_group
+}
diff --git a/ncdump/type_preorder.cdl b/ncdump/type_preorder.cdl
new file mode 100644
index 000000000..4b888fc6c
--- /dev/null
+++ b/ncdump/type_preorder.cdl
@@ -0,0 +1,13 @@
+netcdf type_preorder {
+
+group: preorder {
+types:
+  ubyte enum test_enum_type {OPTION1 = 0, OPTION2 = 1, OPTION3 = 2} ;
+} // group preorder
+
+group: test_group {
+  variables:
+  	/preorder/test_enum_type test_variable ;
+  		/preorder/test_enum_type test_variable:_FillValue = OPTION1 ;
+  } // group test_group
+}


Test patch:
diff --git a/ncdump/test_scope.sh b/ncdump/test_scope.sh
new file mode 100755
index 000000000..98bf9ef61
--- /dev/null
+++ b/ncdump/test_scope.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+
+if test "x$srcdir" = x ; then srcdir=`pwd`; fi 
+. ../test_common.sh
+
+set -x
+set -e
+
+# Test cases
+# group_only - type defined in same group as var/attr
+# ancestor_only - type defined in some ancestor group of var/attr
+# ancestor_subgroup - type defined in both ancestor group and subgroup
+# preorder - type defined in some preceding, non ancestor group
+
+TSTS="type_group_only type_ancestor_only type_ancestor_subgroup type_preorder"
+
+SETUP=1
+
+setup() {
+    ${NCGEN} -4 -lb ${srcdir}/$1.cdl
+}
+
+testscope() {
+${NCCOPY} ${execdir}/$1.nc ${execdir}/$1_copy.nc
+${NCDUMP} -h -n $1 ${execdir}/$1_copy.nc > copy_$1.cdl
+diff -wB ${srcdir}/$1.cdl ${execdir}/copy_$1.cdl
+REFT=`${execdir}/printfqn ${execdir}/$1.nc test_variable`
+COPYT=`${execdir}/printfqn ${execdir}/$1_copy.nc test_variable`
+if test "x$REFT" != "x$COPYT" ; then
+  echo "***Fail: ref=${REFT} copy=${COPYT}"
+fi
+}
+
+if test "x$SETUP" = x1 ; then
+for t in $TSTS ; do
+  setup $t
+done
+fi
+
+for t in $TSTS ; do
+  testscope $t
+done
+
+exit 0
+
+