Fix under-parenthesized XLogRecHasBlockRef() macro.

tglsfdc · tglsfdc · commit 9e4114822919 · 2021-04-20T17:01:49.000-04:00
Commit f003d9f left this macro with inadequate (or, one could say, too much) parenthesization. Which was catastrophic to the correctness of calls such as "if (!XLogRecHasBlockRef(record, 1)) ...". There are only a few of those, which perhaps explains why we didn't notice immediately (with our general weakness of WAL replay testing being another factor). I found it by debugging intermittent replay failures like 2021-04-08 14:33:30.191 EDT [29463] PANIC: failed to locate backup block with ID 1 2021-04-08 14:33:30.191 EDT [29463] CONTEXT: WAL redo at 0/95D3438 for SPGist/ADD_NODE: off 1; blkref #0: rel 1663/16384/25998, blk 1
diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h
@@ -385,8 +385,8 @@ extern bool DecodeXLogRecord(XLogReaderState *state,
 #define XLogRecMaxBlockId(decoder) ((decoder)->record->max_block_id)
 #define XLogRecGetBlock(decoder, i) (&(decoder)->record->blocks[(i)])
 #define XLogRecHasBlockRef(decoder, block_id) \
-	((decoder)->record->max_block_id >= (block_id))  && \
-	((decoder)->record->blocks[block_id].in_use)
+	((decoder)->record->max_block_id >= (block_id) && \
+	 (decoder)->record->blocks[block_id].in_use)
 #define XLogRecHasBlockImage(decoder, block_id) \
 	((decoder)->record->blocks[block_id].has_image)
 #define XLogRecBlockImageApply(decoder, block_id) \
