Fixed HDFFV-10933

Description:
    Fixed to allow the creation of a dataset when the combination of type,
    space, etc doesn't work for filter and the filter is optional. Currently,
    it was supposed to be skipped as indicated in the documentation, but it
    was not skipped and the creation failed.
    The function H5Z_ignore_filters was added and used in H5D__create.
Platforms tested:
    Linux/64 (jelly)

4 files changed, 190 insertions, 13 deletions

diff --git a/src/H5Dint.c b/src/H5Dint.c
index 6c0fd76..177ff1f 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -1220,18 +1220,24 @@ H5D__create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
 
     /* Check if the dataset has a non-default DCPL & get important values, if so */
     if(new_dset->shared->dcpl_id != H5P_DATASET_CREATE_DEFAULT) {
-        H5O_layout_t    *layout;        /* Dataset's layout information */
-        H5O_pline_t     *pline;         /* Dataset's I/O pipeline information */
-        H5O_fill_t      *fill;          /* Dataset's fill value info */
-        H5O_efl_t       *efl;           /* Dataset's external file list info */
+        H5O_layout_t *layout;        /* Dataset's layout information */
+        H5O_pline_t  *pline;         /* Dataset's I/O pipeline information */
+        H5O_fill_t   *fill;          /* Dataset's fill value info */
+        H5O_efl_t    *efl;           /* Dataset's external file list info */
+        htri_t       ignore_filters = FALSE; /* Ignore optional filters or not */
 
-        /* Check if the filters in the DCPL can be applied to this dataset */
-        if(H5Z_can_apply(new_dset->shared->dcpl_id, new_dset->shared->type_id) < 0)
-            HGOTO_ERROR(H5E_ARGS, H5E_CANTINIT, NULL, "I/O filters can't operate on this dataset")
+        if((ignore_filters = H5Z_ignore_filters(new_dset->shared->dcpl_id, type, space))<0)
+            HGOTO_ERROR(H5E_ARGS, H5E_CANTINIT, NULL, "H5Z_has_optional_filter() failed")
 
-        /* Make the "set local" filter callbacks for this dataset */
-        if(H5Z_set_local(new_dset->shared->dcpl_id, new_dset->shared->type_id) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to set local filter parameters")
+        if(FALSE == ignore_filters) {
+            /* Check if the filters in the DCPL can be applied to this dataset */
+            if(H5Z_can_apply(new_dset->shared->dcpl_id, new_dset->shared->type_id) < 0)
+                HGOTO_ERROR(H5E_ARGS, H5E_CANTINIT, NULL, "I/O filters can't operate on this dataset")
+
+            /* Make the "set local" filter callbacks for this dataset */
+            if(H5Z_set_local(new_dset->shared->dcpl_id, new_dset->shared->type_id) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to set local filter parameters")
+        } /* ignore_filters */
 
         /* Get new dataset's property list object */
         if(NULL == (dc_plist = (H5P_genplist_t *)H5I_object(new_dset->shared->dcpl_id)))
@@ -1255,9 +1261,11 @@ H5D__create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
             HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, NULL, "can't retrieve external file list")
         efl_copied = TRUE;
 
-        /* Check that chunked layout is used if filters are enabled */
-        if(pline->nused > 0 && H5D_CHUNKED != layout->type)
-            HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, NULL, "filters can only be used with chunked layout")
+        if(FALSE == ignore_filters) {
+            /* Check that chunked layout is used if filters are enabled */
+            if(pline->nused > 0 && H5D_CHUNKED != layout->type)
+                HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, NULL, "filters can only be used with chunked layout")
+            }
 
         /* Check if the alloc_time is the default and error out */
         if(fill->alloc_time == H5D_ALLOC_TIME_DEFAULT)
diff --git a/src/H5Z.c b/src/H5Z.c
index 93d7df9..4c90138 100644
--- a/src/H5Z.c
+++ b/src/H5Z.c
@@ -1003,6 +1003,73 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function: H5Z_ignore_filters
+ *
+ * Purpose:  Determine whether filters can be ignored.
+ *
+ * Description:
+ *      When the filters are optional (i.e., H5Z_FLAG_OPTIONAL is provided,)
+ *      if any of the following conditions is met, the filters will be ignored:
+ *          - dataspace is either H5S_NULL or H5S_SCALAR
+ *          - datatype is variable-length (string or non-string)
+ *      However, if any of these conditions exists and a filter is not
+ *      optional, the function will produce an error.
+ *
+ * Return:   Non-negative(TRUE/FALSE) on success
+ *           Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+htri_t
+H5Z_ignore_filters(hid_t dcpl_id, const H5T_t *type, const H5S_t *space)
+{
+    H5P_genplist_t  *dc_plist;   /* Dataset creation property list object */
+    H5O_pline_t     pline;       /* Object's I/O pipeline information */
+    H5S_class_t     space_class;            /* To check class of space */
+    H5T_class_t     type_class;             /* To check if type is VL */
+    bool            bad_for_filters = FALSE;/* Suitable to have filters */
+    htri_t          ret_value = FALSE;      /* TRUE for ignoring filters */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    if (NULL == (dc_plist = (H5P_genplist_t *)H5I_object(dcpl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get dataset creation property list")
+
+    /* Get pipeline information */
+    if (H5P_peek(dc_plist, H5O_CRT_PIPELINE_NAME, &pline) < 0)
+        HGOTO_ERROR(H5E_PLINE, H5E_CANTGET, FAIL, "can't retrieve pipeline filter")
+
+    /* Get datatype and dataspace classes for quick access */
+    space_class = H5S_GET_EXTENT_TYPE(space);
+    type_class = H5T_get_class(type, FALSE);
+
+    /* These conditions are not suitable for filters */
+    bad_for_filters = (H5S_NULL == space_class || H5S_SCALAR == space_class
+        || H5T_VLEN == type_class
+        || (H5T_STRING == type_class && TRUE == H5T_is_variable_str(type)));
+
+    /* When these conditions occur, if there are required filters in pline,
+       then report a failure, otherwise, set flag that they can be ignored */
+    if (bad_for_filters) {
+        size_t ii;
+        if (pline.nused > 0) {
+            for (ii = 0; ii < pline.nused; ii++)
+            {
+                if (!(pline.filter[ii].flags & H5Z_FLAG_OPTIONAL))
+                    HGOTO_ERROR(H5E_PLINE, H5E_CANTFILTER, FAIL, "not suitable for filters")
+            }
+
+            /* All filters are optional, we can ignore them */
+            ret_value = TRUE;
+        }
+    } /* bad for filters */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5Z_ignore_filters() */
+
+
+/*-------------------------------------------------------------------------
  * Function: H5Z_modify
  *
  * Purpose:  Modify filter parameters for specified pipeline.
diff --git a/src/H5Zprivate.h b/src/H5Zprivate.h
index fbc6fc4..62d85f2 100644
--- a/src/H5Zprivate.h
+++ b/src/H5Zprivate.h
@@ -27,6 +27,9 @@ typedef struct H5Z_filter_info_t H5Z_filter_info_t;
 /* Private headers needed by this file */
 #include "H5Tprivate.h"		/* Datatypes				*/
 
+/* Forward declarations (for prototype) */
+struct H5S_t;
+
 /**************************/
 /* Library Private Macros */
 /**************************/
@@ -89,6 +92,7 @@ H5_DLL herr_t H5Z_can_apply(hid_t dcpl_id, hid_t type_id);
 H5_DLL herr_t H5Z_set_local(hid_t dcpl_id, hid_t type_id);
 H5_DLL herr_t H5Z_can_apply_direct(const struct H5O_pline_t *pline);
 H5_DLL herr_t H5Z_set_local_direct(const struct H5O_pline_t *pline);
+H5_DLL htri_t H5Z_ignore_filters(hid_t dcpl_id, const H5T_t *type, const struct H5S_t *space);
 H5_DLL H5Z_filter_info_t *H5Z_filter_info(const struct H5O_pline_t *pline,
         H5Z_filter_t filter);
 H5_DLL htri_t H5Z_filter_in_pline(const struct H5O_pline_t *pline, H5Z_filter_t filter);
diff --git a/test/dsets.c b/test/dsets.c
index f7e90a5..aa9f10a 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -112,6 +112,8 @@ const char *FILENAME[] = {
 #define DSET_FLETCHER32_NAME_3      "fletcher32_3"
 #define DSET_SHUF_DEF_FLET_NAME     "shuffle+deflate+fletcher32"
 #define DSET_SHUF_DEF_FLET_NAME_2   "shuffle+deflate+fletcher32_2"
+#define DSET_OPTIONAL_SCALAR        "dataset_with_scalar_space"
+#define DSET_OPTIONAL_VLEN          "dataset_with_vlen_type"
 #ifdef H5_HAVE_FILTER_SZIP
 #define DSET_SZIP_NAME              "szip"
 #define DSET_SHUF_SZIP_FLET_NAME    "shuffle+szip+fletcher32"
@@ -5771,6 +5773,101 @@ error:
 } /* end test_can_apply2() */
 
 
+/*-------------------------------------------------------------------------
+ * Function:    test_optional_filters
+ *
+ * Purpose:     Tests that H5Dcreate2 will not fail when a combination of
+ *              type, space, etc... doesn't work for a filter and filter is
+ *              optional.
+ *
+ * Return:      Success:    SUCCEED
+ *              Failure:    FAIL
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              12 August 2020
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+test_optional_filters(hid_t file)
+{
+    unsigned int level = 9;
+    unsigned int cd_values[1] = {level};
+    size_t  cd_nelmts = 1;
+    hsize_t dim1d[1];                  /* Dataspace dimensions */
+    hid_t   dsid = H5I_INVALID_HID;    /* Dataset ID */
+    hid_t   sid = H5I_INVALID_HID;     /* Dataspace ID */
+    hid_t   strtid = H5I_INVALID_HID;  /* Datatype ID for string */
+    hid_t   vlentid = H5I_INVALID_HID; /* Datatype ID for vlen */
+    hid_t   dcplid = H5I_INVALID_HID;  /* Dataspace creation property list ID */
+
+    TESTING("dataset with optional filters");
+
+    /* Create dcpl with special filter */
+    if((dcplid = H5Pcreate(H5P_DATASET_CREATE)) < 0) TEST_ERROR;
+
+    /* Create the datatype */
+    if((strtid = H5Tcreate(H5T_STRING, H5T_VARIABLE)) < 0) TEST_ERROR;
+
+    /* Create the data space */
+    if((sid = H5Screate(H5S_SCALAR)) < 0) TEST_ERROR;
+
+    /* The filter is optional. */
+    if(H5Pset_filter(dcplid, H5Z_FILTER_DEFLATE, H5Z_FLAG_OPTIONAL, cd_nelmts, cd_values) < 0)
+        TEST_ERROR;
+
+    /* Create dataset with optional filter */
+    if((dsid = H5Dcreate2(file, DSET_OPTIONAL_SCALAR, strtid, sid, H5P_DEFAULT, dcplid, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+
+    /* Close dataset */
+    if(H5Dclose(dsid) < 0) TEST_ERROR;
+
+    /* Close dataspace */
+    if(H5Sclose(sid) < 0) TEST_ERROR;
+
+    /* Close datatype */
+    if(H5Tclose(strtid) < 0) TEST_ERROR;
+
+    /* Set dataspace dimensions */
+    dim1d[0]=DIM1;
+
+    /* Create a non-scalar dataspace */
+    if((sid = H5Screate_simple(1, dim1d, NULL)) < 0) TEST_ERROR;
+
+    /* Create a vlen datatype */
+    if((vlentid = H5Tvlen_create(H5T_NATIVE_INT)) < 0) TEST_ERROR;
+
+    /* Create dataset with optional filter */
+    if((dsid = H5Dcreate2(file, DSET_OPTIONAL_VLEN, vlentid, sid, H5P_DEFAULT, dcplid, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+
+    /* Close dataset */
+    if(H5Dclose(dsid) < 0) TEST_ERROR;
+
+    /* Close dataspace */
+    if(H5Sclose(sid) < 0) TEST_ERROR;
+
+    /* Close datatype */
+    if(H5Tclose(vlentid) < 0) TEST_ERROR;
+
+    /* Close dataset creation property list */
+    if(H5Pclose(dcplid) < 0) TEST_ERROR;
+
+    PASSED();
+    return SUCCEED;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Dclose(dsid);
+        H5Sclose(sid);
+        H5Pclose(dcplid);
+        H5Tclose(strtid);
+        H5Tclose(vlentid);
+    } H5E_END_TRY;
+    return FAIL;
+} /* end test_optional_filters() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    test_can_apply_szip
@@ -13858,6 +13955,7 @@ main(void)
                 nerrors += (test_missing_filter(file) < 0        ? 1 : 0);
                 nerrors += (test_can_apply(file) < 0                ? 1 : 0);
                 nerrors += (test_can_apply2(file) < 0                ? 1 : 0);
+                nerrors += (test_optional_filters(file) < 0          ? 1 : 0);
                 nerrors += (test_set_local(my_fapl) < 0                ? 1 : 0);
                 nerrors += (test_can_apply_szip(file) < 0        ? 1 : 0);
                 nerrors += (test_compare_dcpl(file) < 0                ? 1 : 0);