From 82a91c7bd38897d4ec25bf540603df218ef56972 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 23 Dec 2012 14:07:47 -0500
Subject: [PATCH] Prevent failure when RowExpr or XmlExpr is parse-analyzed
 twice.

transformExpr() is required to cope with already-transformed expression
trees, for various ugly-but-not-quite-worth-cleaning-up reasons.  However,
some of its newer subroutines hadn't gotten the memo.  This accounts for
bug #7763 from Norbert Buchmuller: transformRowExpr() was overwriting the
previously determined type of a RowExpr during CREATE TABLE LIKE INCLUDING
INDEXES.  Additional investigation showed that transformXmlExpr had the
same kind of problem, but all the other cases seem to be safe.

Andres Freund and Tom Lane
---
 src/backend/parser/gram.y       |  1 +
 src/backend/parser/parse_expr.c | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index de6734dfd7..0fd9636919 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11037,6 +11037,7 @@ makeXmlExpr(XmlExprOp op, char *name, List *named_args, List *args,
 	x->args = args;
 	/* xmloption, if relevant, must be filled in by caller */
 	/* type and typmod will be filled in during parse analysis */
+	x->type = InvalidOid;			/* marks the node as not analyzed */
 	x->location = location;
 	return (Node *) x;
 }
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 90ff8d8268..6721643a8a 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -89,6 +89,8 @@ static Expr *make_distinct_op(ParseState *pstate, List *opname,
  *	function argument to the required type (via coerce_type())
  *	can apply transformExpr to an already-transformed subexpression.
  *	An example here is "SELECT count(*) + 1.0 FROM table".
+ *	3. CREATE TABLE t1 (LIKE t2 INCLUDING INDEXES) can pass in
+ *	already-transformed index expressions.
  * While it might be possible to eliminate these cases, the path of
  * least resistance so far has been to ensure that transformExpr() does
  * no damage if applied to an already-transformed tree.  This is pretty
@@ -1551,7 +1553,13 @@ transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
 static Node *
 transformRowExpr(ParseState *pstate, RowExpr *r)
 {
-	RowExpr    *newr = makeNode(RowExpr);
+	RowExpr    *newr;
+
+	/* If we already transformed this node, do nothing */
+	if (OidIsValid(r->row_typeid))
+		return (Node *) r;
+
+	newr = makeNode(RowExpr);
 
 	/* Transform the field expressions */
 	newr->args = transformExpressionList(pstate, r->args);
@@ -1642,16 +1650,23 @@ transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
 static Node *
 transformXmlExpr(ParseState *pstate, XmlExpr *x)
 {
-	XmlExpr    *newx = makeNode(XmlExpr);
+	XmlExpr    *newx;
 	ListCell   *lc;
 	int			i;
 
+	/* If we already transformed this node, do nothing */
+	if (OidIsValid(x->type))
+		return (Node *) x;
+
+	newx = makeNode(XmlExpr);
 	newx->op = x->op;
 	if (x->name)
 		newx->name = map_sql_identifier_to_xml_name(x->name, false, false);
 	else
 		newx->name = NULL;
 	newx->xmloption = x->xmloption;
+	newx->type = XMLOID;		/* this just marks the node as transformed */
+	newx->typmod = -1;
 	newx->location = x->location;
 
 	/*