Doc: update pg_list.h header comments to include XidLists.

tglsfdc · tglsfdc · commit 0efecb5518c9 · 2022-12-17T10:31:25.000-05:00
I realize that the XidList infrastructure is rather incomplete,
but failing to mention it in adjacent comments takes that a bit
too far.
diff --git a/src/include/nodes/pg_list.h b/src/include/nodes/pg_list.h
@@ -15,16 +15,18 @@
  * Non-empty lists have a header, which will not be relocated as long as the
  * list remains non-empty, and an expansible data array.
  *
- * We support three types of lists:
+ * We support four types of lists:
  *
  *	T_List: lists of pointers
  *		(in practice usually pointers to Nodes, but not always;
  *		declared as "void *" to minimize casting annoyances)
  *	T_IntList: lists of integers
  *	T_OidList: lists of Oids
+ *	T_XidList: lists of TransactionIds
+ *		(the XidList infrastructure is less complete than the other cases)
  *
- * (At the moment, ints and Oids are the same size, but they may not
- * always be so; try to be careful to maintain the distinction.)
+ * (At the moment, ints, Oids, and XIDs are the same size, but they may not
+ * always be so; be careful to use the appropriate list type for your data.)
  *
  *
  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
@@ -50,7 +52,7 @@ typedef union ListCell
 
 typedef struct List
 {
-	NodeTag		type;			/* T_List, T_IntList, or T_OidList */
+	NodeTag		type;			/* T_List, T_IntList, T_OidList, or T_XidList */
 	int			length;			/* number of elements currently present */
 	int			max_length;		/* allocated length of elements[] */
 	ListCell   *elements;		/* re-allocatable array of cells */

Original file line number	Diff line number	Diff line change
`@@ -15,16 +15,18 @@`
`15`	`15`	`* Non-empty lists have a header, which will not be relocated as long as the`
`16`	`16`	`* list remains non-empty, and an expansible data array.`
`17`	`17`	`*`
`18`		`- * We support three types of lists:`
	`18`	`+ * We support four types of lists:`
`19`	`19`	`*`
`20`	`20`	`* T_List: lists of pointers`
`21`	`21`	`* (in practice usually pointers to Nodes, but not always;`
`22`	`22`	`* declared as "void *" to minimize casting annoyances)`
`23`	`23`	`* T_IntList: lists of integers`
`24`	`24`	`* T_OidList: lists of Oids`
	`25`	`+ * T_XidList: lists of TransactionIds`
	`26`	`+ * (the XidList infrastructure is less complete than the other cases)`
`25`	`27`	`*`
`26`		`- * (At the moment, ints and Oids are the same size, but they may not`
`27`		`- * always be so; try to be careful to maintain the distinction.)`
	`28`	`+ * (At the moment, ints, Oids, and XIDs are the same size, but they may not`
	`29`	`+ * always be so; be careful to use the appropriate list type for your data.)`
`28`	`30`	`*`
`29`	`31`	`*`
`30`	`32`	`* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group`
`@@ -50,7 +52,7 @@ typedef union ListCell`
`50`	`52`
`51`	`53`	`typedef struct List`
`52`	`54`	`{`
`53`		`- NodeTag type; /* T_List, T_IntList, or T_OidList */`
	`55`	`+ NodeTag type; /* T_List, T_IntList, T_OidList, or T_XidList */`
`54`	`56`	`int length; /* number of elements currently present */`
`55`	`57`	`int max_length; /* allocated length of elements[] */`
`56`	`58`	`ListCell elements; / re-allocatable array of cells */`