fix: fix nullbitmap shift error when trimming data blocks.

source/common/src/tdatablock.c

@@ -1590,7 +1590,7 @@ static void doShiftBitmap(char* nullBitmap, size_t n, size_t total) {
         i += 1;
       }
     } else if (n > 8) {
-      int32_t remain = (total % 8 <= tail) ? 1 : 0;
+      int32_t remain = (total % 8 != 0 && total % 8 <= tail) ? 1 : 0;
       int32_t gap = len - newLen - remain;
       while (i < newLen) {
         uint8_t v = p[i + gap];

tests/system-test/2-query/limit.py

@@ -288,7 +288,7 @@ class TDTestCase:
         tdSql.checkData(0, 3, 5.000000000)
         tdSql.checkData(0, 4, 5.000000000)
         tdSql.checkData(0, 5, 0.000000000)
-        tdSql.checkData(0, 7, None)
+        tdSql.checkData(0, 7, 1)
         tdSql.checkData(0, 8, "binary5")
         tdSql.checkData(0, 9, "nchar5")
         tdSql.checkData(1, 8, None)