CREATE DOMAIN ... DEFAULT NULL failed because gram.y special-cases DEFAULT

NULL and DefineDomain didn't.  Bug goes all the way back to original coding
of domains.  Per bug #3396 from Sergey Burladyan.

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 3dea8bf633062aa689a2cbb9648329d6d1022233..07160b3de9af794ae797598745f5ca4159338a7f 100644 (file)
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/commands/typecmds.c,v 1.15 2002/09/21 18:39:25 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/commands/typecmds.c,v 1.15.2.1 2007/06/20 18:16:30 tgl Exp $
  *
  * DESCRIPTION
  *       The "DefineFoo" routines take the parse tree and pick out the
@@ -397,6 +397,7 @@ DefineDomain(CreateDomainStmt *stmt)
        Node       *defaultExpr = NULL;
        char       *defaultValue = NULL;
        char       *defaultValueBin = NULL;
+       bool            saw_default = false;
        bool            typNotNull = false;
        bool            nullDefined = false;
        Oid                     basetypelem;
@@ -493,42 +494,52 @@ DefineDomain(CreateDomainStmt *stmt)
        foreach(listptr, schema)
        {
                Constraint *colDef = lfirst(listptr);
-               ParseState *pstate;
 
                switch (colDef->contype)
                {
+                       case CONSTR_DEFAULT:
                                /*
                                 * The inherited default value may be overridden by the
-                                * user with the DEFAULT <expr> statement.
-                                *
-                                * We have to search the entire constraint tree returned as
-                                * we don't want to cook or fiddle too much.
+                                * user with the DEFAULT <expr> clause ... but only once.
                                 */
-                       case CONSTR_DEFAULT:
-                               if (defaultExpr)
+                               if (saw_default)
                                        elog(ERROR, "CREATE DOMAIN has multiple DEFAULT expressions");
-                               /* Create a dummy ParseState for transformExpr */
-                               pstate = make_parsestate(NULL);
-
-                               /*
-                                * Cook the colDef->raw_expr into an expression. Note:
-                                * Name is strictly for error message
-                                */
-                               defaultExpr = cookDefault(pstate, colDef->raw_expr,
-                                                                                 basetypeoid,
-                                                                                 stmt->typename->typmod,
-                                                                                 domainName);
-
-                               /*
-                                * Expression must be stored as a nodeToString result, but
-                                * we also require a valid textual representation (mainly
-                                * to make life easier for pg_dump).
-                                */
-                               defaultValue = deparse_expression(defaultExpr,
-                                                                                 deparse_context_for(domainName,
-                                                                                                                         InvalidOid),
-                                                                                                 false, false);
-                               defaultValueBin = nodeToString(defaultExpr);
+                               saw_default = true;
+
+                               if (colDef->raw_expr)
+                               {
+                                       ParseState *pstate;
+
+                                       /* Create a dummy ParseState for transformExpr */
+                                       pstate = make_parsestate(NULL);
+
+                                       /*
+                                        * Cook the colDef->raw_expr into an expression.
+                                        * Note: name is strictly for error message
+                                        */
+                                       defaultExpr = cookDefault(pstate, colDef->raw_expr,
+                                                                                         basetypeoid,
+                                                                                         stmt->typename->typmod,
+                                                                                         domainName);
+
+                                       /*
+                                        * Expression must be stored as a nodeToString result, but
+                                        * we also require a valid textual representation (mainly
+                                        * to make life easier for pg_dump).
+                                        */
+                                       defaultValue =
+                                               deparse_expression(defaultExpr,
+                                                                                  deparse_context_for(domainName,
+                                                                                                                          InvalidOid),
+                                                                                  false, false);
+                                       defaultValueBin = nodeToString(defaultExpr);
+                               }
+                               else
+                               {
+                                       /* DEFAULT NULL is same as not having a default */
+                                       defaultValue = NULL;
+                                       defaultValueBin = NULL;
+                               }
                                break;
 
                                /*