Undo unintentional ABI break in struct ResultRelInfo.

Commits aac2c9b4f 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.   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
index 418c81f4be2c30a9b9b0787fcddef8a772bfb21a..17b0ec513864acff0de5cbbe07105d4eb8ee8a63 100644 (file)
--- 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;
 
 /* ----------------