Allow CREATE TABLE IF EXIST so succeed if the schema is nonexistent

Previously, CREATE TABLE IF EXIST threw an error if the schema was
nonexistent.  This was done by passing 'missing_ok' to the function that
looks up the schema oid.

src/backend/catalog/aclchk.c

@@ -755,7 +755,7 @@ objectsInSchemaToOids(GrantObjectType objtype, List *nspnames)
 		Oid			namespaceId;
 		List	   *objs;
 
-		namespaceId = LookupExplicitNamespace(nspname);
+		namespaceId = LookupExplicitNamespace(nspname, false);
 
 		switch (objtype)
 		{

src/backend/catalog/namespace.c

@@ -291,7 +291,11 @@ RangeVarGetRelidExtended(const RangeVar *relation, LOCKMODE lockmode,
 				{
 					Oid			namespaceId;
 
-					namespaceId = LookupExplicitNamespace(relation->schemaname);
+					namespaceId = LookupExplicitNamespace(relation->schemaname, missing_ok);
+					/*
+					 *	For missing_ok, allow a non-existant schema name
+					 *	to throw the error below (namespaceId == InvalidOid).
+					 */
 					if (namespaceId != myTempNamespace)
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
@@ -306,7 +310,10 @@ RangeVarGetRelidExtended(const RangeVar *relation, LOCKMODE lockmode,
 			Oid			namespaceId;
 
 			/* use exact schema given */
-			namespaceId = LookupExplicitNamespace(relation->schemaname);
+			namespaceId = LookupExplicitNamespace(relation->schemaname, missing_ok);
+			if (missing_ok && !OidIsValid(namespaceId))
+				relId = InvalidOid;
+			else
 				relId = get_relname_relid(relation->relname, namespaceId);
 		}
 		else
@@ -919,7 +926,7 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 	}
 	else
 	{
@@ -1453,7 +1460,7 @@ OpernameGetOprid(List *names, Oid oprleft, Oid oprright)
 		Oid			namespaceId;
 		HeapTuple	opertup;
 
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 		opertup = SearchSysCache4(OPERNAMENSP,
 								  CStringGetDatum(opername),
 								  ObjectIdGetDatum(oprleft),
@@ -1551,7 +1558,7 @@ OpernameGetCandidates(List *names, char oprkind)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 	}
 	else
 	{
@@ -2093,7 +2100,10 @@ get_ts_parser_oid(List *names, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			prsoid = InvalidOid;
+		else
 			prsoid = GetSysCacheOid2(TSPARSERNAMENSP,
 									 PointerGetDatum(parser_name),
 									 ObjectIdGetDatum(namespaceId));
@@ -2216,7 +2226,10 @@ get_ts_dict_oid(List *names, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			dictoid = InvalidOid;
+		else
 			dictoid = GetSysCacheOid2(TSDICTNAMENSP,
 									  PointerGetDatum(dict_name),
 									  ObjectIdGetDatum(namespaceId));
@@ -2340,7 +2353,10 @@ get_ts_template_oid(List *names, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			tmploid = InvalidOid;
+		else
 			tmploid = GetSysCacheOid2(TSTEMPLATENAMENSP,
 									  PointerGetDatum(template_name),
 									  ObjectIdGetDatum(namespaceId));
@@ -2463,7 +2479,10 @@ get_ts_config_oid(List *names, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			cfgoid = InvalidOid;
+		else
 			cfgoid = GetSysCacheOid2(TSCONFIGNAMENSP,
 									 PointerGetDatum(config_name),
 									 ObjectIdGetDatum(namespaceId));
@@ -2657,7 +2676,7 @@ LookupNamespaceNoError(const char *nspname)
  * Returns the namespace OID.  Raises ereport if any problem.
  */
 Oid
-LookupExplicitNamespace(const char *nspname)
+LookupExplicitNamespace(const char *nspname, bool missing_ok)
 {
 	Oid			namespaceId;
 	AclResult	aclresult;
@@ -2676,7 +2695,9 @@ LookupExplicitNamespace(const char *nspname)
 		 */
 	}
 
-	namespaceId = get_namespace_oid(nspname, false);
+	namespaceId = get_namespace_oid(nspname, missing_ok);
+	if (missing_ok && !OidIsValid(namespaceId))
+		return InvalidOid;
 	
 	aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
@@ -3248,7 +3269,9 @@ get_collation_oid(List *name, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			return InvalidOid;
 
 		/* first try for encoding-specific entry, then any-encoding */
 		colloid = GetSysCacheOid3(COLLNAMEENCNSP,
@@ -3318,7 +3341,10 @@ get_conversion_oid(List *name, bool missing_ok)
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (missing_ok && !OidIsValid(namespaceId))
+			conoid = InvalidOid;
+		else
 			conoid = GetSysCacheOid2(CONNAMENSP,
 									 PointerGetDatum(conversion_name),
 									 ObjectIdGetDatum(namespaceId));

src/backend/commands/indexcmds.c

@@ -1264,7 +1264,7 @@ GetIndexOpClass(List *opclass, Oid attrType,
 		/* Look in specific schema only */
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 		tuple = SearchSysCache3(CLAAMNAMENSP,
 								ObjectIdGetDatum(accessMethodId),
 								PointerGetDatum(opcname),

src/backend/commands/opclasscmds.c

@@ -103,7 +103,7 @@ OpFamilyCacheLookup(Oid amID, List *opfamilyname, bool missing_ok)
 		/* Look in specific schema only */
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 		htup = SearchSysCache3(OPFAMILYAMNAMENSP,
 							   ObjectIdGetDatum(amID),
 							   PointerGetDatum(opfname),
@@ -179,7 +179,7 @@ OpClassCacheLookup(Oid amID, List *opclassname, bool missing_ok)
 		/* Look in specific schema only */
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname);
+		namespaceId = LookupExplicitNamespace(schemaname, false);
 		htup = SearchSysCache3(CLAAMNAMENSP,
 							   ObjectIdGetDatum(amID),
 							   PointerGetDatum(opcname),

src/backend/commands/trigger.c

@@ -4226,7 +4226,8 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt)
 			 */
 			if (constraint->schemaname)
 			{
-				Oid			namespaceId = LookupExplicitNamespace(constraint->schemaname);
+				Oid			namespaceId = LookupExplicitNamespace(constraint->schemaname,
+																  false);
 
 				namespacelist = list_make1_oid(namespaceId);
 			}

src/backend/parser/parse_oper.c

@@ -1027,7 +1027,7 @@ make_oper_cache_key(OprCacheKey *key, List *opname, Oid ltypeId, Oid rtypeId)
 	if (schemaname)
 	{
 		/* search only in exact schema given */
-		key->search_path[0] = LookupExplicitNamespace(schemaname);
+		key->search_path[0] = LookupExplicitNamespace(schemaname, false);
 	}
 	else
 	{

src/backend/parser/parse_type.c

@@ -149,7 +149,7 @@ LookupTypeName(ParseState *pstate, const TypeName *typeName,
 			/* Look in specific schema only */
 			Oid			namespaceId;
 
-			namespaceId = LookupExplicitNamespace(schemaname);
+			namespaceId = LookupExplicitNamespace(schemaname, false);
 			typoid = GetSysCacheOid2(TYPENAMENSP,
 									 PointerGetDatum(typname),
 									 ObjectIdGetDatum(namespaceId));

src/backend/utils/adt/xml.c

@@ -2678,7 +2678,7 @@ schema_to_xml(PG_FUNCTION_ARGS)
 	Oid			nspid;
 
 	schemaname = NameStr(*name);
-	nspid = LookupExplicitNamespace(schemaname);
+	nspid = LookupExplicitNamespace(schemaname, false);
 
 	PG_RETURN_XML_P(stringinfo_to_xmltype(schema_to_xml_internal(nspid, NULL,
 									   nulls, tableforest, targetns, true)));
@@ -2724,7 +2724,7 @@ schema_to_xmlschema_internal(const char *schemaname, bool nulls,
 
 	result = makeStringInfo();
 
-	nspid = LookupExplicitNamespace(schemaname);
+	nspid = LookupExplicitNamespace(schemaname, false);
 
 	xsd_schema_element_start(result, targetns);
 
@@ -2782,7 +2782,7 @@ schema_to_xml_and_xmlschema(PG_FUNCTION_ARGS)
 	StringInfo	xmlschema;
 
 	schemaname = NameStr(*name);
-	nspid = LookupExplicitNamespace(schemaname);
+	nspid = LookupExplicitNamespace(schemaname, false);
 
 	xmlschema = schema_to_xmlschema_internal(schemaname, nulls,
 											 tableforest, targetns);

src/include/catalog/namespace.h

@@ -106,7 +106,7 @@ extern void DeconstructQualifiedName(List *names,
 						 char **nspname_p,
 						 char **objname_p);
 extern Oid	LookupNamespaceNoError(const char *nspname);
-extern Oid	LookupExplicitNamespace(const char *nspname);
+extern Oid	LookupExplicitNamespace(const char *nspname, bool missing_ok);
 extern Oid	get_namespace_oid(const char *nspname, bool missing_ok);
 
 extern Oid	LookupCreationNamespace(const char *nspname);