TO_DATE: MTR coverage omissions, round 1

Lines with zero coverage (99/1238):

===File sql/item_func.h:

    923 : +  virtual bool get_date_common(THD *thd, MYSQL_TIME *ltime,

    926 : +    DBUG_ASSERT(0);

    927 : +    return 0;

===File sql/item_timefunc.cc:

    668 : +      else if (format_char == *val)

    670 : +        val++;

    686 : +    case FMT_YYY:

    687 : +      tmp= (char*) val + MY_MIN(3, val_len);

    688 : +      l_time->year= ((int) my_strtoll10(val, &tmp, &error) +

    689 : +                     l_time->year/1000*1000);

    690 : +      val= tmp;

    691 : +      break;

    698 : +    case FMT_Y:

    699 : +      tmp= (char*) val + MY_MIN(1, val_len);

    700 : +      l_time->year= ((int) my_strtoll10(val, &tmp, &error) +

    701 : +                     l_time->year/10*10);

    702 : +      val= tmp;

    703 : +      break;

    713 : +    case FMT_RRRR:

    716 : +      tmp= (char*) val + MY_MIN(4, val_len);

    717 : +      year= (uint)my_strtoll10(val, &tmp, &error);

    718 : +      l_time->year= year > 100 ? year : oracle_year_2000_handling(year);

    719 : +      val= tmp;

    720 : +      break;

    730 : +        goto error;

    749 : +        goto error;

    804 : +        goto error;

    811 : +        val+= 2;

    814 : +        daypart= 12;

    815 : +        val+= 4;

    820 : +        goto error;

    826 : +        goto error;

    828 : +    case FMT_DY:

    829 : +      if ((weekday= check_word(locale->ab_day_names, val, val_end, &val)) <= 0)

    830 : +        goto error;

    831 : +      break;

    839 : +    default:

    840 : +      goto error;

    850 : +      goto error;

    859 : +      goto error;

    889 : +    } while (++val != val_end);

   2608 : +          goto error;

   2616 : +          goto error;

   2626 : +            goto error;

   2634 : +            goto error;

   2650 : +        goto error;

   2672 : +        goto error;

   2701 : +        goto error;

   2704 : +        goto error;

   2726 : +        goto error;

   2762 : +        goto error;

   2793 : +          goto error;

   2802 : +          goto error;

   2813 : +          goto error;

   2856 : +            goto error;

   2894 : +        goto error;

   2936 : +          goto error;

   2943 : +               !my_charset_latin1.strnncoll(ptr+1, 4, "YYYY", 4))

   2976 : +          goto error;

   2983 : +          goto error;

   3213 : +        goto err_exit;

   3225 : +        goto err_exit;

   3238 : +          goto err_exit;

   3245 : +          goto err_exit;

   3250 : +        goto err_exit;

   4671 : +      return true;

   4678 : +          return true;

   4682 : +      return true;

   4695 : +      return true;                  // Empty values are not allowed

   4706 : +        return 1;

   4743 : +        return;

   4797 : +void Item_func_to_date::print(String *str, enum_query_type query_type)

   4799 : +  str->append(func_name_cstring());

   4800 : +  str->append('(');

   4801 : +  args[0]->print(str, query_type);

   4802 : +  if (arg_count == 3)

   4804 : +    str->append(STRING_WITH_LEN("DEFAULT "));

   4805 : +    args[2]->print(str, query_type);

   4806 : +    str->append(STRING_WITH_LEN(" ON CONVERSION ERROR"));

   4808 : +  str->append(',');

   4809 : +  args[1]->print(str, query_type);

   4810 : +  if (nls_param.length)

   4812 : +    str->append(',');

   4813 : +    str->append(nls_param);

   4815 : +  str->append(')');

   4816 : +}

   4823 : +    return true;

   4833 : +    my_error(ER_ILLEGAL_PARAMETER_DATA_TYPES2_FOR_OPERATION, MYF(0),

   4834 : +             args[0]->type_handler()->name().ptr(),

   4835 : +             args[2]->type_handler()->name().ptr(), func_name());

   4836 : +    return TRUE;

   4839 : +    return TRUE;

   4841 : +    internal_charset= &my_charset_utf8mb4_general_ci;

   4877 : +    goto error;

   4884 : +      goto error;

   4888 : +      goto error;

===File sql/item_timefunc.h:

   1842 : +  Item *do_get_copy(THD *thd) const override

   1843 : +  { return get_item_copy<Item_func_to_date>(thd, this); }

===File sql/sql_yacc.yy:

  10421 : +            MYSQL_YYABORT;

  10428 : +            MYSQL_YYABORT;

SET timestamp = UNIX_TIMESTAMP('2025-12-21');

SELECT TO_DATE('0', 'YYY') AS result;

SELECT TO_DATE('25', 'YYY') AS result;

SELECT TO_DATE('1000', 'YYY') AS result;

SELECT TO_DATE('0', 'RRRR') AS result;

SELECT TO_DATE('25', 'RRRR') AS result;

SELECT TO_DATE('999', 'RRRR') AS result;

SELECT TO_DATE('1000', 'RRRR') AS result;

SELECT TO_DATE('10000', 'RRRR') AS result;

SELECT TO_DATE('0', 'Y') AS result;

SELECT TO_DATE('1', 'Y') AS result;

SELECT TO_DATE('10', 'Y') AS result;

SELECT TO_DATE('Sun', 'DY');

SELECT TO_DATE('sun', 'DY');

SELECT TO_DATE('xxx', 'DY');

SET STATEMENT timestamp = UNIX_TIMESTAMP('2025-12-19') FOR SELECT TO_DATE('FRI', 'DY');

SET timestamp = DEFAULT;

CREATE TABLE t (d DATETIME, vd VARCHAR(32) AS (TO_DATE(d DEFAULT '2000-01-01' ON CONVERSION ERROR, 'YYYY-MM-DD')));

SHOW CREATE TABLE t;

DROP TABLE t;

This currently fails, see MDEV-38403

CREATE TABLE t (c GEOMETRYCOLLECTION);

SELECT TO_DATE(c,'YYYY-MM-DD') FROM t;

DROP TABLE t;