Fix WITH attached to a nested set operation (UNION/INTERSECT/EXCEPT).

Parse analysis neglected to cover the case of a WITH clause attached to an
intermediate-level set operation; it only handled WITH at the top level
or WITH attached to a leaf-level SELECT.  Per report from Adam Mackler.

In HEAD, I rearranged the order of SelectStmt's fields to put withClause
with the other fields that can appear on non-leaf SelectStmts.  In back
branches, leave it alone to avoid a possible ABI break for third-party
code.

Back-patch to 8.4 where WITH support was added.

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 9d9de7c4251a0eb305141f0aa4524a34ba1526e3..799930ad611b6e09403a3d14c5738f47cb2f3bab 100644 (file)
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2494,12 +2494,12 @@ _copySelectStmt(const SelectStmt *from)
        COPY_NODE_FIELD(groupClause);
        COPY_NODE_FIELD(havingClause);
        COPY_NODE_FIELD(windowClause);
-       COPY_NODE_FIELD(withClause);
        COPY_NODE_FIELD(valuesLists);
        COPY_NODE_FIELD(sortClause);
        COPY_NODE_FIELD(limitOffset);
        COPY_NODE_FIELD(limitCount);
        COPY_NODE_FIELD(lockingClause);
+       COPY_NODE_FIELD(withClause);
        COPY_SCALAR_FIELD(op);
        COPY_SCALAR_FIELD(all);
        COPY_NODE_FIELD(larg);

diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 6d4030a3224e272009e8240e9688c4de8abe170d..802b0636714d2c34013275132c531ebc7ae1bdd6 100644 (file)
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -976,12 +976,12 @@ _equalSelectStmt(const SelectStmt *a, const SelectStmt *b)
        COMPARE_NODE_FIELD(groupClause);
        COMPARE_NODE_FIELD(havingClause);
        COMPARE_NODE_FIELD(windowClause);
-       COMPARE_NODE_FIELD(withClause);
        COMPARE_NODE_FIELD(valuesLists);
        COMPARE_NODE_FIELD(sortClause);
        COMPARE_NODE_FIELD(limitOffset);
        COMPARE_NODE_FIELD(limitCount);
        COMPARE_NODE_FIELD(lockingClause);
+       COMPARE_NODE_FIELD(withClause);
        COMPARE_SCALAR_FIELD(op);
        COMPARE_SCALAR_FIELD(all);
        COMPARE_NODE_FIELD(larg);

diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index 813d1da1a2816b3a9a6df159ce5f3f616683be58..b130902dcf2d7f5c4b9775a205129adb7096f26b 100644 (file)
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -2909,8 +2909,6 @@ raw_expression_tree_walker(Node *node,
                                        return true;
                                if (walker(stmt->windowClause, context))
                                        return true;
-                               if (walker(stmt->withClause, context))
-                                       return true;
                                if (walker(stmt->valuesLists, context))
                                        return true;
                                if (walker(stmt->sortClause, context))
@@ -2921,6 +2919,8 @@ raw_expression_tree_walker(Node *node,
                                        return true;
                                if (walker(stmt->lockingClause, context))
                                        return true;
+                               if (walker(stmt->withClause, context))
+                                       return true;
                                if (walker(stmt->larg, context))
                                        return true;
                                if (walker(stmt->rarg, context))

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 91b54265afe6dadb4f171ec9abdf5ff7ec9c69c5..b83bd1c9fdb132d8b76e65759deade49b73fb4eb 100644 (file)
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2037,12 +2037,12 @@ _outSelectStmt(StringInfo str, const SelectStmt *node)
        WRITE_NODE_FIELD(groupClause);
        WRITE_NODE_FIELD(havingClause);
        WRITE_NODE_FIELD(windowClause);
-       WRITE_NODE_FIELD(withClause);
        WRITE_NODE_FIELD(valuesLists);
        WRITE_NODE_FIELD(sortClause);
        WRITE_NODE_FIELD(limitOffset);
        WRITE_NODE_FIELD(limitCount);
        WRITE_NODE_FIELD(lockingClause);
+       WRITE_NODE_FIELD(withClause);
        WRITE_ENUM_FIELD(op, SetOperation);
        WRITE_BOOL_FIELD(all);
        WRITE_NODE_FIELD(larg);

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index bfd3ab941a771ac8a994afc72967fb61c3321120..263edb5a7a61d3a3c2ea5f1a5f9a255024d86bad 100644 (file)
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -1322,6 +1322,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
        Node       *limitOffset;
        Node       *limitCount;
        List       *lockingClause;
+       WithClause *withClause;
        Node       *node;
        ListCell   *left_tlist,
                           *lct,
@@ -1338,14 +1339,6 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 
        qry->commandType = CMD_SELECT;
 
-       /* process the WITH clause independently of all else */
-       if (stmt->withClause)
-       {
-               qry->hasRecursive = stmt->withClause->recursive;
-               qry->cteList = transformWithClause(pstate, stmt->withClause);
-               qry->hasModifyingCTE = pstate->p_hasModifyingCTE;
-       }
-
        /*
         * Find leftmost leaf SelectStmt.  We currently only need to do this in
         * order to deliver a suitable error message if there's an INTO clause
@@ -1375,11 +1368,13 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
        limitOffset = stmt->limitOffset;
        limitCount = stmt->limitCount;
        lockingClause = stmt->lockingClause;
+       withClause = stmt->withClause;
 
        stmt->sortClause = NIL;
        stmt->limitOffset = NULL;
        stmt->limitCount = NULL;
        stmt->lockingClause = NIL;
+       stmt->withClause = NULL;
 
        /* We don't support FOR UPDATE/SHARE with set ops at the moment. */
        if (lockingClause)
@@ -1387,6 +1382,14 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
 
+       /* Process the WITH clause independently of all else */
+       if (withClause)
+       {
+               qry->hasRecursive = withClause->recursive;
+               qry->cteList = transformWithClause(pstate, withClause);
+               qry->hasModifyingCTE = pstate->p_hasModifyingCTE;
+       }
+
        /*
         * Recursively transform the components of the tree.
         */
@@ -1572,10 +1575,10 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
                                 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
 
        /*
-        * If an internal node of a set-op tree has ORDER BY, LIMIT, or FOR UPDATE
-        * clauses attached, we need to treat it like a leaf node to generate an
-        * independent sub-Query tree.  Otherwise, it can be represented by a
-        * SetOperationStmt node underneath the parent Query.
+        * If an internal node of a set-op tree has ORDER BY, LIMIT, FOR UPDATE,
+        * or WITH clauses attached, we need to treat it like a leaf node to
+        * generate an independent sub-Query tree.  Otherwise, it can be
+        * represented by a SetOperationStmt node underneath the parent Query.
         */
        if (stmt->op == SETOP_NONE)
        {
@@ -1586,7 +1589,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
        {
                Assert(stmt->larg != NULL && stmt->rarg != NULL);
                if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
-                       stmt->lockingClause)
+                       stmt->lockingClause || stmt->withClause)
                        isLeaf = true;
                else
                        isLeaf = false;

diff --git a/src/backend/parser/parse_cte.c b/src/backend/parser/parse_cte.c
index 2a7d4cd07244054a9e3cea3554712eb133662384..d04fb6dec1491a6f01f428171550846645005884 100644 (file)
--- a/src/backend/parser/parse_cte.c
+++ b/src/backend/parser/parse_cte.c
@@ -678,6 +678,18 @@ checkWellFormedRecursion(CteState *cstate)
                if (cstate->selfrefcount != 1)  /* shouldn't happen */
                        elog(ERROR, "missing recursive reference");
 
+               /* WITH mustn't contain self-reference, either */
+               if (stmt->withClause)
+               {
+                       cstate->curitem = i;
+                       cstate->innerwiths = NIL;
+                       cstate->selfrefcount = 0;
+                       cstate->context = RECURSION_SUBLINK;
+                       checkWellFormedRecursionWalker((Node *) stmt->withClause->ctes,
+                                                                                  cstate);
+                       Assert(cstate->innerwiths == NIL);
+               }
+
                /*
                 * Disallow ORDER BY and similar decoration atop the UNION. These
                 * don't make sense because it's impossible to figure out what they
@@ -933,7 +945,7 @@ checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate)
                                                                                           cstate);
                                checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
                                                                                           cstate);
-                               break;
+                               /* stmt->withClause is intentionally ignored here */
                                break;
                        case SETOP_EXCEPT:
                                if (stmt->all)
@@ -952,6 +964,7 @@ checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate)
                                                                                           cstate);
                                checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
                                                                                           cstate);
+                               /* stmt->withClause is intentionally ignored here */
                                break;
                        default:
                                elog(ERROR, "unrecognized set op: %d",

diff --git a/src/backend/parser/parse_type.c b/src/backend/parser/parse_type.c
index 871a7d1ce303267154731911ea2d6bbb0a2f9db8..cf2ff0cf70a98ca50fbf697c8ff8e8dd75899599 100644 (file)
--- a/src/backend/parser/parse_type.c
+++ b/src/backend/parser/parse_type.c
@@ -705,12 +705,12 @@ parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p)
                stmt->groupClause != NIL ||
                stmt->havingClause != NULL ||
                stmt->windowClause != NIL ||
-               stmt->withClause != NULL ||
                stmt->valuesLists != NIL ||
                stmt->sortClause != NIL ||
                stmt->limitOffset != NULL ||
                stmt->limitCount != NULL ||
                stmt->lockingClause != NIL ||
+               stmt->withClause != NULL ||
                stmt->op != SETOP_NONE)
                goto fail;
        if (list_length(stmt->targetList) != 1)

diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 1f89cd51595d0fd658813e3c5278f7fb9073dec5..119e1ed2f6e18872cfd3758b9303fb2835e5695a 100644 (file)
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1016,7 +1016,6 @@ typedef struct SelectStmt
        List       *groupClause;        /* GROUP BY clauses */
        Node       *havingClause;       /* HAVING conditional-expression */
        List       *windowClause;       /* WINDOW window_name AS (...), ... */
-       WithClause *withClause;         /* WITH clause */
 
        /*
         * In a "leaf" node representing a VALUES list, the above fields are all
@@ -1036,6 +1035,7 @@ typedef struct SelectStmt
        Node       *limitOffset;        /* # of result tuples to skip */
        Node       *limitCount;         /* # of result tuples to return */
        List       *lockingClause;      /* FOR UPDATE (list of LockingClause's) */
+       WithClause *withClause;         /* WITH clause */
 
        /*
         * These fields are used only in upper-level SelectStmts.

diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out
index 2a41736cc8a2cc7d24cb562a441f8ae33e396800..0d59ea3fdf97481d6db4bed15fb02609029ddfe8 100644 (file)
--- a/src/test/regress/expected/with.out
+++ b/src/test/regress/expected/with.out
@@ -1158,6 +1158,57 @@ SELECT * FROM t;
  10
 (55 rows)
 
+--
+-- test WITH attached to intermediate-level set operation
+--
+WITH outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM innermost
+         UNION SELECT 3)
+)
+SELECT * FROM outermost;
+ x 
+---
+ 1
+ 2
+ 3
+(3 rows)
+
+WITH outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM outermost  -- fail
+         UNION SELECT * FROM innermost)
+)
+SELECT * FROM outermost;
+ERROR:  relation "outermost" does not exist
+LINE 4:          SELECT * FROM outermost  
+                               ^
+DETAIL:  There is a WITH item named "outermost", but it cannot be referenced from this part of the query.
+HINT:  Use WITH RECURSIVE, or re-order the WITH items to remove forward references.
+WITH RECURSIVE outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM outermost
+         UNION SELECT * FROM innermost)
+)
+SELECT * FROM outermost;
+ x 
+---
+ 1
+ 2
+(2 rows)
+
+WITH RECURSIVE outermost(x) AS (
+  WITH innermost as (SELECT 2 FROM outermost) -- fail
+    SELECT * FROM innermost
+    UNION SELECT * from outermost
+)
+SELECT * FROM outermost;
+ERROR:  recursive reference to query "outermost" must not appear within a subquery
+LINE 2:   WITH innermost as (SELECT 2 FROM outermost) 
+                                           ^
 --
 -- Data-modifying statements in WITH
 --

diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql
index 9c6732b961190b114ff6ca4e66acee9c2a9f30f2..22fdddc4eeafa2de36c1eaf57b20ec0d44d27df3 100644 (file)
--- a/src/test/regress/sql/with.sql
+++ b/src/test/regress/sql/with.sql
@@ -539,6 +539,41 @@ WITH RECURSIVE t(j) AS (
 )
 SELECT * FROM t;
 
+--
+-- test WITH attached to intermediate-level set operation
+--
+
+WITH outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM innermost
+         UNION SELECT 3)
+)
+SELECT * FROM outermost;
+
+WITH outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM outermost  -- fail
+         UNION SELECT * FROM innermost)
+)
+SELECT * FROM outermost;
+
+WITH RECURSIVE outermost(x) AS (
+  SELECT 1
+  UNION (WITH innermost as (SELECT 2)
+         SELECT * FROM outermost
+         UNION SELECT * FROM innermost)
+)
+SELECT * FROM outermost;
+
+WITH RECURSIVE outermost(x) AS (
+  WITH innermost as (SELECT 2 FROM outermost) -- fail
+    SELECT * FROM innermost
+    UNION SELECT * from outermost
+)
+SELECT * FROM outermost;
+
 --
 -- Data-modifying statements in WITH
 --