Refactor parseAffectedRows and add tests

async_postgres/pg_types.nim

@@ -1912,12 +1912,10 @@ converter toRow*(cells: seq[Option[seq[byte]]]): Row =
 proc parseAffectedRows*(tag: string): int64 =
   ## Extract row count from command tag (e.g. "UPDATE 3" -> 3, "INSERT 0 1" -> 1).
   let parts = tag.split(' ')
-  if parts.len > 0:
-    try:
-      return parseBiggestInt(parts[^1])
-    except ValueError:
-      return 0
-  return 0
+  try:
+    parseBiggestInt(parts[^1])
+  except ValueError, OverflowDefect:
+    0
 
 proc initCommandResult*(tag: string): CommandResult {.inline.} =
   CommandResult(commandTag: tag)

tests/test_types.nim

@@ -989,6 +989,27 @@ suite "parseAffectedRows":
   test "non-numeric tag":
     check parseAffectedRows("CREATE TABLE") == 0
 
+  test "COPY tag":
+    check parseAffectedRows("COPY 100") == 100
+
+  test "MERGE tag":
+    check parseAffectedRows("MERGE 7") == 7
+
+  test "MOVE tag":
+    check parseAffectedRows("MOVE 12") == 12
+
+  test "FETCH tag":
+    check parseAffectedRows("FETCH 4") == 4
+
+  test "trailing whitespace falls back to 0":
+    check parseAffectedRows("UPDATE 3 ") == 0
+
+  test "overflow falls back to 0":
+    check parseAffectedRows("UPDATE 99999999999999999999999999") == 0
+
+  test "single-token DDL tag":
+    check parseAffectedRows("BEGIN") == 0
+
 suite "Option accessors":
   test "getStrOpt some":
     let row: Row = @[some(toBytes("hello"))]