Undo unintentional ABI break in struct ResultRelInfo.

tglsfdc · tglsfdc · commit 6bfacd368bb4 · 2024-11-16T12:58:26.000-05:00
Commits aac2c9b et al. added a bool field to struct ResultRelInfo. That's no problem in the master branch, but in released branches care must be taken when modifying publicly-visible structs to avoid an ABI break for extensions. Frequently we solve that by adding the new field at the end of the struct, and that's what was done here. But ResultRelInfo has stricter constraints than just about any other node type in Postgres. Some executor APIs require extensions to index into arrays of ResultRelInfo, which means that any change whatever in sizeof(ResultRelInfo) causes a fatal ABI break. Fortunately, this is easy to fix, because the new field can be squeezed into available padding space instead --- indeed, that's where it was put in master, so this fix also removes a cross-branch coding variation. Per report from Pavan Deolasee. Patch v14-v17 only; earlier versions did not gain the extra field, nor is there any problem in master. Discussion: https://postgr.es/m/CABOikdNmVBC1LL6pY26dyxAS2f+gLZvTsNt=2XbcyG7WxXVBBQ@mail.gmail.com
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
@@ -484,6 +484,9 @@ typedef struct ResultRelInfo
 	/* Have the projection and the slots above been initialized? */
 	bool		ri_projectNewInfoValid;
 
+	/* updates do LockTuple() before oldtup read; see README.tuplock */
+	bool		ri_needLockTagTuple;
+
 	/* triggers to be fired, if any */
 	TriggerDesc *ri_TrigDesc;
 
@@ -592,9 +595,6 @@ typedef struct ResultRelInfo
 	 * one of its ancestors; see ExecCrossPartitionUpdateForeignKey().
 	 */
 	List	   *ri_ancestorResultRels;
-
-	/* updates do LockTuple() before oldtup read; see README.tuplock */
-	bool		ri_needLockTagTuple;
 } ResultRelInfo;
 
 /* ----------------
