Fix bug in attribute type conversion wiith compound types (#2016)

* Fix bug in attribute type conversion where the background buffer would
not be initialized with the destination contents when necessary.  Other
minor simplification.

* Committing clang-format changes

* Fix warnings.

* Address review comments.

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

2 files changed, 175 insertions, 9 deletions

diff --git a/src/H5Aint.c b/src/H5Aint.c
index fb54f0c..4403da8 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -740,6 +740,8 @@ H5A__read(const H5A_t *attr, const H5T_t *mem_type, void *buf)
 
             /* Check for type conversion required */
             if (!H5T_path_noop(tpath)) {
+                H5T_bkg_t need_bkg; /* Background buffer type */
+
                 if ((src_id = H5I_register(H5I_DATATYPE, H5T_copy(attr->shared->dt, H5T_COPY_ALL), FALSE)) <
                         0 ||
                     (dst_id = H5I_register(H5I_DATATYPE, H5T_copy(mem_type, H5T_COPY_ALL), FALSE)) < 0)
@@ -749,12 +751,23 @@ H5A__read(const H5A_t *attr, const H5T_t *mem_type, void *buf)
                 buf_size = nelmts * MAX(src_type_size, dst_type_size);
                 if (NULL == (tconv_buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                     HGOTO_ERROR(H5E_ATTR, H5E_NOSPACE, FAIL, "memory allocation failed")
-                if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
-                    HGOTO_ERROR(H5E_ATTR, H5E_NOSPACE, FAIL, "memory allocation failed")
 
                 /* Copy the attribute data into the buffer for conversion */
                 H5MM_memcpy(tconv_buf, attr->shared->data, (src_type_size * nelmts));
 
+                /* Check if we need a background buffer */
+                need_bkg = H5T_path_bkg(tpath);
+
+                if (need_bkg) {
+                    /* Allocate background buffer */
+                    if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
+                        HGOTO_ERROR(H5E_ATTR, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+                    /* Copy the application buffer into the background buffer if necessary */
+                    if (need_bkg == H5T_BKG_YES)
+                        H5MM_memcpy(bkg_buf, buf, (dst_type_size * nelmts));
+                }
+
                 /* Perform datatype conversion.  */
                 if (H5T_convert(tpath, src_id, dst_id, nelmts, (size_t)0, (size_t)0, tconv_buf, bkg_buf) < 0)
                     HGOTO_ERROR(H5E_ATTR, H5E_CANTENCODE, FAIL, "datatype conversion failed")
@@ -804,9 +817,8 @@ done:
 herr_t
 H5A__write(H5A_t *attr, const H5T_t *mem_type, const void *buf)
 {
-    uint8_t    *tconv_buf   = NULL;       /* datatype conv buffer */
-    hbool_t     tconv_owned = FALSE;      /* Whether the datatype conv buffer is owned by attribute */
-    uint8_t    *bkg_buf     = NULL;       /* temp conversion buffer */
+    uint8_t    *tconv_buf = NULL;         /* datatype conv buffer */
+    uint8_t    *bkg_buf   = NULL;         /* temp conversion buffer */
     hssize_t    snelmts;                  /* elements in attribute */
     size_t      nelmts;                   /* elements in attribute */
     H5T_path_t *tpath  = NULL;            /* conversion information*/
@@ -840,6 +852,8 @@ H5A__write(H5A_t *attr, const H5T_t *mem_type, const void *buf)
 
         /* Check for type conversion required */
         if (!H5T_path_noop(tpath)) {
+            H5T_bkg_t need_bkg; /* Background buffer type */
+
             if ((src_id = H5I_register(H5I_DATATYPE, H5T_copy(mem_type, H5T_COPY_ALL), FALSE)) < 0 ||
                 (dst_id = H5I_register(H5I_DATATYPE, H5T_copy(attr->shared->dt, H5T_COPY_ALL), FALSE)) < 0)
                 HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, FAIL, "unable to register types for conversion")
@@ -848,12 +862,33 @@ H5A__write(H5A_t *attr, const H5T_t *mem_type, const void *buf)
             buf_size = nelmts * MAX(src_type_size, dst_type_size);
             if (NULL == (tconv_buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                 HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed")
-            if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
-                HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed")
 
             /* Copy the user's data into the buffer for conversion */
             H5MM_memcpy(tconv_buf, buf, (src_type_size * nelmts));
 
+            /* Check if we need a background buffer */
+            if (H5T_detect_class(attr->shared->dt, H5T_VLEN, FALSE))
+                need_bkg = H5T_BKG_YES;
+            else
+                need_bkg = H5T_path_bkg(tpath);
+
+            if (need_bkg) {
+                /* Use the existing attribute data buffer, if present, as the background buffer,
+                 * otherwise allocate one.  Note we don't need to track which one it is since both
+                 * use the "attr_buf" free list block. */
+                if (attr->shared->data) {
+                    bkg_buf            = attr->shared->data;
+                    attr->shared->data = NULL;
+
+                    /* Clear background buffer if it's not supposed to be initialized with file
+                     * contents */
+                    if (need_bkg == H5T_BKG_TEMP)
+                        HDmemset(bkg_buf, 0, dst_type_size * nelmts);
+                }
+                else if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
+                    HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed")
+            }
+
             /* Perform datatype conversion */
             if (H5T_convert(tpath, src_id, dst_id, nelmts, (size_t)0, (size_t)0, tconv_buf, bkg_buf) < 0)
                 HGOTO_ERROR(H5E_ATTR, H5E_CANTENCODE, FAIL, "datatype conversion failed")
@@ -864,7 +899,7 @@ H5A__write(H5A_t *attr, const H5T_t *mem_type, const void *buf)
 
             /* Set the pointer to the attribute data to the converted information */
             attr->shared->data = tconv_buf;
-            tconv_owned        = TRUE;
+            tconv_buf          = NULL;
         } /* end if */
         /* No type conversion necessary */
         else {
@@ -890,7 +925,7 @@ done:
         HDONE_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to close temporary object")
     if (dst_id >= 0 && H5I_dec_ref(dst_id) < 0)
         HDONE_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to close temporary object")
-    if (tconv_buf && !tconv_owned)
+    if (tconv_buf)
         tconv_buf = H5FL_BLK_FREE(attr_buf, tconv_buf);
     if (bkg_buf)
         bkg_buf = H5FL_BLK_FREE(attr_buf, bkg_buf);
diff --git a/test/dtypes.c b/test/dtypes.c
index 547e890..1cbaf6c 100644
--- a/test/dtypes.c
+++ b/test/dtypes.c
@@ -3365,6 +3365,136 @@ error:
 } /* end test_compound_15() */
 
 /*-------------------------------------------------------------------------
+ * Function:    test_compound_15_attr
+ *
+ * Purpose:     Tests that conversion occurs correctly when the source is
+ *              subset of the destination, but there is extra space at the
+ *              end of the source type. This one tests on attribute while
+ *              test_compound_15() tests on dataset.  That's the only
+ *              difference.
+ *
+ * Return:      Success:        0
+ *
+ *              Failure:        number of errors
+ *
+ * Programmer:  Ray Lu
+ *              14 July 2022
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_compound_15_attr(void)
+{
+    typedef struct cmpd_struct {
+        int i1;
+        int i2;
+    } cmpd_struct;
+
+    cmpd_struct wdata1 = {1254, 5471};
+    cmpd_struct rdata;
+    int         wdata2[2]  = {1, 2};
+    hid_t       file       = H5I_INVALID_HID;
+    hid_t       cmpd_m_tid = H5I_INVALID_HID;
+    hid_t       cmpd_f_tid = H5I_INVALID_HID;
+    hid_t       space_id   = H5I_INVALID_HID;
+    hid_t       attr_id    = H5I_INVALID_HID;
+    hsize_t     dim1[1];
+    char        filename[1024];
+
+    TESTING("compound subset conversion with extra space in source for attribute");
+
+    /* Create File */
+    h5_fixname(FILENAME[3], H5P_DEFAULT, filename, sizeof(filename));
+    if ((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        FAIL_PUTS_ERROR("Can't create file!\n");
+
+    /* Create file compound datatype */
+    if ((cmpd_f_tid = H5Tcreate(H5T_COMPOUND, sizeof(struct cmpd_struct))) < 0)
+        FAIL_PUTS_ERROR("Can't create datatype!\n");
+
+    if (H5Tinsert(cmpd_f_tid, "i1", HOFFSET(struct cmpd_struct, i1), H5T_NATIVE_INT) < 0)
+        FAIL_PUTS_ERROR("Can't insert field 'i1'\n");
+
+    if (H5Tinsert(cmpd_f_tid, "i2", HOFFSET(struct cmpd_struct, i2), H5T_NATIVE_INT) < 0)
+        FAIL_PUTS_ERROR("Can't insert field 'i2'\n");
+
+    /* Create memory compound datatype */
+    if ((cmpd_m_tid = H5Tcreate(H5T_COMPOUND, sizeof(struct cmpd_struct))) < 0)
+        FAIL_PUTS_ERROR("Can't create datatype!\n");
+
+    if (H5Tinsert(cmpd_m_tid, "i1", (size_t)0, H5T_NATIVE_INT) < 0)
+        FAIL_PUTS_ERROR("Can't insert field 'i1'\n");
+
+    /* Create space, dataset, write wdata1 */
+    dim1[0] = 1;
+    if ((space_id = H5Screate_simple(1, dim1, NULL)) < 0)
+        FAIL_PUTS_ERROR("Can't create space\n");
+
+    if ((attr_id = H5Acreate_by_name(file, ".", "attr_cmpd", cmpd_f_tid, space_id, H5P_DEFAULT, H5P_DEFAULT,
+                                     H5P_DEFAULT)) < 0)
+        FAIL_PUTS_ERROR("Can't create dataset\n");
+
+    if (H5Awrite(attr_id, cmpd_f_tid, &wdata1) < 0)
+        FAIL_PUTS_ERROR("Can't write data\n");
+
+    /* Write wdata2.  The use of cmpd_m_tid here should cause only the first
+     * element of wdata2 to be written. */
+    if (H5Awrite(attr_id, cmpd_m_tid, &wdata2) < 0)
+        FAIL_PUTS_ERROR("Can't write data\n");
+
+    /* Read data */
+    if (H5Aread(attr_id, cmpd_f_tid, &rdata) < 0)
+        FAIL_PUTS_ERROR("Can't read data\n");
+
+    /* Check for correctness of read data */
+    if (rdata.i1 != wdata2[0] || rdata.i2 != wdata1.i2)
+        FAIL_PUTS_ERROR("incorrect read data\n");
+
+    /* Now try reading only the i1 field, verify it does not overwrite i2 in the
+     * read buffer */
+    rdata.i1 = wdata1.i1;
+    rdata.i2 = wdata2[1];
+
+    /* Read data */
+    if (H5Aread(attr_id, cmpd_m_tid, &rdata) < 0)
+        FAIL_PUTS_ERROR("Can't read data\n");
+
+    /* Check for correctness of read data */
+    if (rdata.i1 != wdata2[0] || rdata.i2 != wdata2[1])
+        FAIL_PUTS_ERROR("incorrect read data\n");
+
+    /* Close */
+    if (H5Aclose(attr_id) < 0)
+        goto error;
+    if (H5Tclose(cmpd_f_tid) < 0)
+        goto error;
+    if (H5Tclose(cmpd_m_tid) < 0)
+        goto error;
+    if (H5Sclose(space_id) < 0)
+        goto error;
+    if (H5Fclose(file) < 0)
+        goto error;
+
+    PASSED();
+    return 0;
+
+error:
+    H5E_BEGIN_TRY
+    {
+        H5Aclose(attr_id);
+        H5Tclose(cmpd_f_tid);
+        H5Tclose(cmpd_m_tid);
+        H5Sclose(space_id);
+        H5Fclose(file);
+    }
+    H5E_END_TRY;
+
+    return 1;
+} /* end test_compound_15_attr() */
+
+/*-------------------------------------------------------------------------
  * Function:    test_compound_16
  *
  * Purpose:     Tests that committed types that can be registered during
@@ -8852,6 +8982,7 @@ main(void)
     }
 
     nerrors += test_compound_15();
+    nerrors += test_compound_15_attr();
     nerrors += test_compound_16();
     nerrors += test_compound_17();
     nerrors += test_compound_18();