Avoid allocating a chunk index for datasets with 0-sized dimensions, until

the dataset is extended.

2 files changed, 5 insertions, 3 deletions

diff --git a/src/H5Dint.c b/src/H5Dint.c
index 4c6814d..574bc0d 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -2296,7 +2296,7 @@ H5D__alloc_storage(const H5D_io_info_t *io_info, H5D_time_alloc_t time_alloc,
      * We assume that external storage is already
      * allocated by the caller, or at least will be before I/O is performed.
      */
-    if(!(H5S_NULL == H5S_GET_EXTENT_TYPE(dset->shared->space) || dset->shared->dcpl_cache.efl.nused > 0)) {
+    if(!(0 == H5S_GET_EXTENT_NPOINTS(dset->shared->space) || dset->shared->dcpl_cache.efl.nused > 0)) {
         /* Get a pointer to the dataset's layout information */
         layout = &(dset->shared->layout);
 
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
index b882578..e257140 100644
--- a/src/H5Dlayout.c
+++ b/src/H5Dlayout.c
@@ -559,10 +559,12 @@ H5D__layout_oh_create(H5F_t *file, H5O_t *oh, H5D_t *dset, hid_t dapl_id)
     } /* end if */
 
     /* Create layout message */
-    /* (Don't make layout message constant unless allocation time is early and non-filtered, since space may not be allocated) */
+    /* (Don't make layout message constant unless allocation time is early and
+     *  non-filtered and has >0 elements, since space may not be allocated -QAK) */
     /* (Note: this is relying on H5D__alloc_storage not calling H5O_msg_write during dataset creation) */
     if(fill_prop->alloc_time == H5D_ALLOC_TIME_EARLY && H5D_COMPACT != layout->type
-            && !dset->shared->dcpl_cache.pline.nused)
+            && !dset->shared->dcpl_cache.pline.nused
+            && (0 != H5S_GET_EXTENT_NPOINTS(dset->shared->space)))
         layout_mesg_flags = H5O_MSG_FLAG_CONSTANT;
     else
         layout_mesg_flags =  0;