Fix pg_get_constraintdef() to ensure CHECK constraints are always shown

with required outer parentheses.  Breakage seems to be leftover from
domain-constraint patches.  This could be smarter about suppressing
extra parens, but at this stage of the release cycle I want certainty
not cuteness.

src/backend/utils/adt/ruleutils.c

@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.156 2003/10/02 22:24:54 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.157 2003/10/04 18:22:59 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -1048,23 +1048,11 @@ pg_get_constraintdef_worker(Oid constraintId, int prettyFlags)
 				Node	   *expr;
 				List	   *context;
 
-				/* Start off the constraint definition */
-
-				/*
-				 * The consrc for CHECK constraints always seems to be
-				 * bracketed, so we don't add extra brackets here.
-				 */
-				appendStringInfo(&buf, "CHECK ");
-
-				/* If we're pretty-printing we need to add brackets */
-				if (prettyFlags != 0)
-					appendStringInfo(&buf, "(");
-
-				/* Fetch constraint source */
+				/* Fetch constraint expression in parsetree form */
 				val = heap_getattr(tup, Anum_pg_constraint_conbin,
 								   RelationGetDescr(conDesc), &isnull);
 				if (isnull)
-					elog(ERROR, "null consrc for constraint %u",
+					elog(ERROR, "null conbin for constraint %u",
 						 constraintId);
 
 				conbin = DatumGetCString(DirectFunctionCall1(textout, val));
@@ -1078,29 +1066,32 @@ pg_get_constraintdef_worker(Oid constraintId, int prettyFlags)
 				if (expr && IsA(expr, List))
 					expr = (Node *) make_ands_explicit((List *) expr);
 
+				/* Set up deparsing context for Var nodes in constraint */
 				if (conForm->conrelid != InvalidOid)
-					/* It's a Relation */
+				{
+					/* relation constraint */
 					context = deparse_context_for(get_rel_name(conForm->conrelid),
 												  conForm->conrelid);
+				}
 				else
-
-					/*
-					 * Since VARNOs aren't allowed in domain constraints,
-					 * relation context isn't required as anything other
-					 * than a shell.
-					 */
-					context = deparse_context_for(get_typname(conForm->contypid),
-												  InvalidOid);
+				{
+					/* domain constraint --- can't have Vars */
+					context = NIL;
+				}
 
 				consrc = deparse_expression_pretty(expr, context, false, false,
 												   prettyFlags, 0);
 
-				/* Append the constraint source */
-				appendStringInfoString(&buf, consrc);
-
-				/* If we're pretty-printing we need to add brackets */
-				if (prettyFlags != 0)
-					appendStringInfo(&buf, ")");
+				/*
+				 * Now emit the constraint definition.  There are cases where
+				 * the constraint expression will be fully parenthesized and
+				 * we don't need the outer parens ... but there are other
+				 * cases where we do need 'em.  Be conservative for now.
+				 *
+				 * Note that simply checking for leading '(' and trailing ')'
+				 * would NOT be good enough, consider "(x > 0) AND (y > 0)".
+				 */
+				appendStringInfo(&buf, "CHECK (%s)", consrc);
 
 				break;
 			}

src/backend/utils/cache/lsyscache.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.107 2003/08/17 19:58:06 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.108 2003/10/04 18:22:59 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -1469,37 +1469,6 @@ get_typtype(Oid typid)
 		return '\0';
 }
 
-/*
- * get_typname
- *		Returns the name of a given type.
- *
- * Returns a palloc'd copy of the string, or NULL if no such type.
- *
- * NOTE: since type name is not unique, be wary of code that uses this
- * for anything except preparing error messages.
- */
-char *
-get_typname(Oid typid)
-{
-	HeapTuple	tp;
-
-	tp = SearchSysCache(TYPEOID,
-						ObjectIdGetDatum(typid),
-						0, 0, 0);
-	if (HeapTupleIsValid(tp))
-	{
-		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
-		char	   *result;
-
-		result = pstrdup(NameStr(typtup->typname));
-		ReleaseSysCache(tp);
-		return result;
-	}
-	else
-		return NULL;
-}
-
-
 /*
  * get_typ_typrelid
  *

src/include/utils/lsyscache.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: lsyscache.h,v 1.81 2003/08/17 19:58:06 tgl Exp $
+ * $Id: lsyscache.h,v 1.82 2003/10/04 18:22:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -83,7 +83,6 @@ extern char get_typtype(Oid typid);
 extern Oid	get_typ_typrelid(Oid typid);
 extern Oid	get_element_type(Oid typid);
 extern Oid	get_array_type(Oid typid);
-extern char *get_typname(Oid relid);
 extern void getTypeInputInfo(Oid type, Oid *typInput, Oid *typElem);
 extern void getTypeOutputInfo(Oid type, Oid *typOutput, Oid *typElem,
 				  bool *typIsVarlena);