Fix datatype confusion in logtape.c's right_offset().

tglsfdc · tglsfdc · commit 2de3c1015cb2 · 2021-12-14T11:46:36.000-05:00
This could only matter if (a) long is wider than int, and (b) the heap of free blocks exceeds UINT_MAX entries, which seems pretty unlikely. Still, it's a theoretical bug, so backpatch to v13 where the typo came in (in commit c02fdc9). In passing, also make swap_nodes() use consistent datatypes. Ma Liangzhu Discussion: https://postgr.es/m/17336-fc4e522d26a750fd@postgresql.org
diff --git a/src/backend/utils/sort/logtape.c b/src/backend/utils/sort/logtape.c
@@ -343,7 +343,7 @@ ltsReadFillBuffer(LogicalTape *lt)
 static inline void
 swap_nodes(long *heap, unsigned long a, unsigned long b)
 {
-	unsigned long swap;
+	long		swap;
 
 	swap = heap[a];
 	heap[a] = heap[b];
@@ -357,7 +357,7 @@ left_offset(unsigned long i)
 }
 
 static inline unsigned long
-right_offset(unsigned i)
+right_offset(unsigned long i)
 {
 	return 2 * i + 2;
 }

Original file line number	Diff line number	Diff line change
`@@ -343,7 +343,7 @@ ltsReadFillBuffer(LogicalTape *lt)`
`343`	`343`	`static inline void`
`344`	`344`	`swap_nodes(long *heap, unsigned long a, unsigned long b)`
`345`	`345`	`{`
`346`		`- unsigned long swap;`
	`346`	`+ long swap;`
`347`	`347`
`348`	`348`	`swap = heap[a];`
`349`	`349`	`heap[a] = heap[b];`
`@@ -357,7 +357,7 @@ left_offset(unsigned long i)`
`357`	`357`	`}`
`358`	`358`
`359`	`359`	`static inline unsigned long`
`360`		`-right_offset(unsigned i)`
	`360`	`+right_offset(unsigned long i)`
`361`	`361`	`{`
`362`	`362`	`return 2 * i + 2;`
`363`	`363`	`}`