Fix pg_rewind debug output to print the source timeline history

hlinnaka · hlinnaka · commit c943e2aae7c5 · 2024-08-08T10:22:30.000+03:00
getTimelineHistory() is called twice, to read the source and the target timeline history files. However, the loop to print the file with the --debug option used the wrong variable when dealing with the source. As a result, the source's history was always printed as empty. Spotted while debugging bug #18575, but this does not fix that bug, just the debugging output. Backpatch to all supported versions. Discussion: https://www.postgresql.org/message-id/092dd515-b7b4-4fd0-8407-ceca2f02f6ec@iki.fi
diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c
@@ -645,6 +645,7 @@ getTimelineHistory(ControlFileData *controlFile, int *nentries)
 		pg_free(histfile);
 	}
 
+	/* In debugging mode, print what we read */
 	if (debug)
 	{
 		int			i;
@@ -656,10 +657,7 @@ getTimelineHistory(ControlFileData *controlFile, int *nentries)
 		else
 			Assert(false);
 
-		/*
-		 * Print the target timeline history.
-		 */
-		for (i = 0; i < targetNentries; i++)
+		for (i = 0; i < *nentries; i++)
 		{
 			TimeLineHistoryEntry *entry;
 

Original file line number	Diff line number	Diff line change
`@@ -645,6 +645,7 @@ getTimelineHistory(ControlFileData controlFile, int nentries)`
`645`	`645`	`pg_free(histfile);`
`646`	`646`	`}`
`647`	`647`
	`648`	`+ /* In debugging mode, print what we read */`
`648`	`649`	`if (debug)`
`649`	`650`	`{`
`650`	`651`	`int i;`
`@@ -656,10 +657,7 @@ getTimelineHistory(ControlFileData controlFile, int nentries)`
`656`	`657`	`else`
`657`	`658`	`Assert(false);`
`658`	`659`
`659`		`- /*`
`660`		`- * Print the target timeline history.`
`661`		`- */`
`662`		`- for (i = 0; i < targetNentries; i++)`
	`660`	`+ for (i = 0; i < *nentries; i++)`
`663`	`661`	`{`
`664`	`662`	`TimeLineHistoryEntry *entry;`
`665`	`663`