Fix an incorrect returned value by H5LTfind_dataset()

H5LTfind_dataset() returns true for non-existing datasets because it only compares up to the length of the searched string, such as "Day" vs "DayNight" (issue HDFGroupGH-4780).

This PR applied the user's patch and added tests.

hl/src/H5LT.c

@@ -1228,7 +1228,7 @@ find_dataset(H5_ATTR_UNUSED hid_t loc_id, const char *name, H5_ATTR_UNUSED const
      * cause the iterator to immediately return that positive value,
      * indicating short-circuit success
      */
-    if (strncmp(name, (char *)op_data, strlen((char *)op_data)) == 0)
+    if (strcmp(name, (char *)op_data) == 0)
         ret = 1;
 
     return ret;

hl/test/test_ds.c

@@ -1341,10 +1341,11 @@ test_detachscales(void)
 static int
 test_char_attachscales(const char *fileext)
 {
-    hid_t fid = -1;
-    hid_t did = -1;
-    char  dsname[32];
-    char  scalename[32];
+    hid_t  fid = -1;
+    hid_t  did = -1;
+    char   dsname[32];
+    char   scalename[32];
+    herr_t ds_existed = 0;
 
     snprintf(dsname, sizeof(dsname), "%s%s", DATASET_NAME, "ac");
 
@@ -1357,6 +1358,14 @@ test_char_attachscales(const char *fileext)
     if (create_char_dataset(fid, "ac", 0) < 0)
         goto out;
 
+    /* test finding dataset dsname */
+    if ((ds_existed = H5LTfind_dataset(fid, dsname)) < 0)
+        goto out;
+    if (ds_existed == 0) {
+        printf("Unexpected result: Dataset \"%s\" does exist\n", dsname);
+        goto out;
+    }
+
     if ((did = H5Dopen2(fid, dsname, H5P_DEFAULT)) >= 0) {
         snprintf(scalename, sizeof(scalename), "%s%s", DS_1_NAME, "ac");
         if (test_attach_scale(fid, did, scalename, DIM0) < 0)

hl/test/test_lite.c

@@ -29,6 +29,9 @@
 #define DSET6_NAME "dataset double"
 #define DSET7_NAME "dataset string"
 
+/* Name of a non-existing dataset, do not create a dataset with this name */
+#define NODS_NAME  "dataset"
+
 #define DIM 6
 
 #define ATTR_NAME_SUB "att"
@@ -60,6 +63,7 @@ test_dsets(void)
     hsize_t     dims[2] = {2, 3};
     hid_t       file_id;
     hid_t       dataset_id;
+    herr_t      ds_existed = 0; /* whether searched ds exists */
     char        data_char_in[DIM] = {1, 2, 3, 4, 5, 6};
     char        data_char_out[DIM];
     short       data_short_in[DIM] = {1, 2, 3, 4, 5, 6};
@@ -348,6 +352,23 @@ test_dsets(void)
     if (strcmp(data_string_in, data_string_out) != 0)
         goto out;
 
+    PASSED();
+
+    /*-------------------------------------------------------------------------
+     * H5LTfind_dataset test
+     *-------------------------------------------------------------------------
+     */
+
+    HL_TESTING2("H5LTfind_dataset");
+
+    /* Try to find a non-existing ds whose name matches existing datasets partially */
+    if ((ds_existed = H5LTfind_dataset(file_id, NODS_NAME)) < 0)
+        goto out;
+    if (ds_existed > 0) {
+        printf("Dataset \"%s\" does not exist.\n", NODS_NAME);
+        goto out;
+    }
+
     /*-------------------------------------------------------------------------
      * end tests
      *-------------------------------------------------------------------------
@@ -1075,7 +1096,7 @@ test_integers(void)
     char  *dt_str;
     size_t str_len;
 
-    HL_TESTING3("\n        text for integer types");
+    HL_TESTING3("        text for integer types");
 
     if ((dtype = H5LTtext_to_dtype("H5T_NATIVE_INT\n", H5LT_DDL)) < 0)
         goto out;
@@ -1881,6 +1902,7 @@ test_text_dtype(void)
 {
     HL_TESTING2("H5LTtext_to_dtype");
 
+    printf("\n");
     if (test_integers() < 0)
         goto out;