Make eval_const_expressions() preserve typmod when simplifying something like

null::char(3) to a simple Const node.  (It already worked for non-null values,
but not when we skipped evaluation of a strict coercion function.)  This
prevents loss of typmod knowledge in situations such as exhibited in bug
#3598.  Unfortunately there seems no good way to fix that bug in 8.1 and 8.2,
because they simply don't carry a typmod for a plain Const node.

In passing I made all the other callers of makeNullConst supply "real" typmod
values too, though I think it probably doesn't matter anywhere else.

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 006076b01f4e0959965e45ec47c7901284532662..10fc87cca8afa2e2656ab550be5da6b982e37026 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.231 2007/08/21 01:11:14 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.232 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3179,12 +3179,15 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 
        if (!defval && GetDomainConstraints(typeOid) != NIL)
        {
-               Oid                     basetype = getBaseType(typeOid);
+               Oid                     baseTypeId;
+               int32           baseTypeMod;
 
-               defval = (Expr *) makeNullConst(basetype);
+               baseTypeMod = typmod;
+               baseTypeId = getBaseTypeAndTypmod(typeOid, &baseTypeMod);
+               defval = (Expr *) makeNullConst(baseTypeId, baseTypeMod);
                defval = (Expr *) coerce_to_target_type(NULL,
                                                                                                (Node *) defval,
-                                                                                               basetype,
+                                                                                               baseTypeId,
                                                                                                typeOid,
                                                                                                typmod,
                                                                                                COERCION_ASSIGNMENT,

diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index 85c3be3e8dd93c43ed2fd69a947bf9af2b7b4cb4..cc165006f5c55808fddb40d4613e2ffac583741b 100644 (file)
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.221 2007/08/31 18:33:40 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.222 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4159,7 +4159,7 @@ ExecInitExpr(Expr *node, PlanState *parent)
                                                 * don't really care what type of NULL it is, so
                                                 * always make an int4 NULL.
                                                 */
-                                               e = (Expr *) makeNullConst(INT4OID);
+                                               e = (Expr *) makeNullConst(INT4OID, -1);
                                        }
                                        estate = ExecInitExpr(e, parent);
                                        outlist = lappend(outlist, estate);

diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index d9d61d4f0bbff614df963b64980b4843d5eec432..429a16cdfea48606503da4c16b971b6aaf114435 100644 (file)
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/nodes/makefuncs.c,v 1.56 2007/06/23 22:12:50 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/nodes/makefuncs.c,v 1.57 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -174,19 +174,20 @@ makeConst(Oid consttype,
 
 /*
  * makeNullConst -
- *       creates a Const node representing a NULL of the specified type
+ *       creates a Const node representing a NULL of the specified type/typmod
  *
- * Note: for all current uses, OK to set typmod of the Const to -1.
+ * This is a convenience routine that just saves a lookup of the type's
+ * storage properties.
  */
 Const *
-makeNullConst(Oid consttype)
+makeNullConst(Oid consttype, int32 consttypmod)
 {
        int16           typLen;
        bool            typByVal;
 
        get_typlenbyval(consttype, &typLen, &typByVal);
        return makeConst(consttype,
-                                        -1,
+                                        consttypmod,
                                         (int) typLen,
                                         (Datum) 0,
                                         true,

diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 4316ddaf5ada76fffc227ad316a413f35559eb6f..24d3b09cf13fc38285c56427a01e0db97d7c8668 100644 (file)
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.248 2007/09/03 00:39:15 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.249 2007/09/06 17:31:58 tgl Exp $
  *
  * HISTORY
  *       AUTHOR                        DATE                    MAJOR EVENT
@@ -2265,7 +2265,7 @@ eval_const_expressions_mutator(Node *node,
 
                /* If all the arguments were constant null, the result is just null */
                if (newargs == NIL)
-                       return (Node *) makeNullConst(coalesceexpr->coalescetype);
+                       return (Node *) makeNullConst(coalesceexpr->coalescetype, -1);
 
                newcoalesce = makeNode(CoalesceExpr);
                newcoalesce->coalescetype = coalesceexpr->coalescetype;
@@ -2833,7 +2833,7 @@ evaluate_function(Oid funcid, Oid result_type, int32 result_typmod, List *args,
         * function is not otherwise immutable.
         */
        if (funcform->proisstrict && has_null_input)
-               return (Expr *) makeNullConst(result_type);
+               return (Expr *) makeNullConst(result_type, result_typmod);
 
        /*
         * Otherwise, can simplify only if all inputs are constants. (For a

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index 6fb7bd9b59f679387bc179d8e4197e5d814c1e0a..79bfe4f7e3effb4d2e0d5f2c6f813620a7043148 100644 (file)
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.156 2007/08/21 01:11:15 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.157 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -816,7 +816,7 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
                         * can't use atttypid here, but it doesn't really matter what type
                         * the Const claims to be.
                         */
-                       newargs = lappend(newargs, makeNullConst(INT4OID));
+                       newargs = lappend(newargs, makeNullConst(INT4OID, -1));
                        continue;
                }
 

diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index dd316f6778a89cb5d4ebd01cc10bc9bc05673261..10726573e92b9f354a0e81809bda10a96b398141 100644 (file)
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.127 2007/01/05 22:19:34 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.128 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1448,7 +1448,7 @@ expandTupleDesc(TupleDesc tupdesc, Alias *eref,
                                         * can't use atttypid here, but it doesn't really matter
                                         * what type the Const claims to be.
                                         */
-                                       *colvars = lappend(*colvars, makeNullConst(INT4OID));
+                                       *colvars = lappend(*colvars, makeNullConst(INT4OID, -1));
                                }
                        }
                        continue;

diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index cc4bc091d249e7272e9f67da6c4ef4e67178829f..6623ac6ed3346c79acd2b88a773f43817c4c5ba5 100644 (file)
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_target.c,v 1.154 2007/02/03 14:06:54 petere Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_target.c,v 1.155 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -393,7 +393,7 @@ transformAssignedExpr(ParseState *pstate,
                         * is not really a source value to work with. Insert a NULL
                         * constant as the source value.
                         */
-                       colVar = (Node *) makeNullConst(attrtype);
+                       colVar = (Node *) makeNullConst(attrtype, attrtypmod);
                }
                else
                {

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index cd1cb54e9af35d5b69658e89e4276cd79af6b8c1..67f46ae4f38025f48e2396be740d860cca2a1a4f 100644 (file)
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.173 2007/03/19 23:38:29 wieck Exp $
+ *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.174 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -193,7 +193,7 @@ AcquireRewriteLocks(Query *parsetree)
                                                         * now-dropped type OID, but it doesn't really
                                                         * matter what type the Const claims to be.
                                                         */
-                                                       aliasvar = (Var *) makeNullConst(INT4OID);
+                                                       aliasvar = (Var *) makeNullConst(INT4OID, -1);
                                                }
                                        }
                                        newaliasvars = lappend(newaliasvars, aliasvar);

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 19b566389051d899647cda96970147caddec805c..6170b2f984d59f80c3d04a088eb758601cb85a58 100644 (file)
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.104 2007/06/11 01:16:25 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.105 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -896,7 +896,8 @@ resolve_one_var(Var *var, ResolveNew_context *context)
                {
                        /* Otherwise replace unmatched var with a null */
                        /* need coerce_to_domain in case of NOT NULL domain constraint */
-                       return coerce_to_domain((Node *) makeNullConst(var->vartype),
+                       return coerce_to_domain((Node *) makeNullConst(var->vartype,
+                                                                                                                  var->vartypmod),
                                                                        InvalidOid, -1,
                                                                        var->vartype,
                                                                        COERCE_IMPLICIT_CAST,

diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h
index 97ee524a0b2e57ee3156c933c4d1be62f60b3972..11c69bd5bbd0e8e83b91a24f9c071277720ea674 100644 (file)
--- a/src/include/nodes/makefuncs.h
+++ b/src/include/nodes/makefuncs.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/makefuncs.h,v 1.59 2007/06/23 22:12:52 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/makefuncs.h,v 1.60 2007/09/06 17:31:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,7 +45,7 @@ extern Const *makeConst(Oid consttype,
                  bool constisnull,
                  bool constbyval);
 
-extern Const *makeNullConst(Oid consttype);
+extern Const *makeNullConst(Oid consttype, int32 consttypmod);
 
 extern Node *makeBoolConst(bool value, bool isnull);