Tighten ALTER FOREIGN TABLE .. SET DATA TYPE checks.

If the foreign table's rowtype is being used as the type of a column in
another table, we can't just up and change its data type.  This was
already checked for composite types and ordinary tables, but we
previously failed to enforce it for foreign tables.

2 files changed, 22 insertions, 23 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7a028991213..6a17399eb6f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3391,8 +3391,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 	 */
 	if (newrel)
 		find_composite_type_dependencies(oldrel->rd_rel->reltype,
-										 RelationGetRelationName(oldrel),
-										 NULL);
+										 oldrel->rd_rel->relkind,
+										 RelationGetRelationName(oldrel));
 
 	/*
 	 * Generate the constraint and default execution states
@@ -3860,9 +3860,8 @@ ATTypedTableRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd,
  * to reject the ALTER.  (How safe is this really?)
  */
 void
-find_composite_type_dependencies(Oid typeOid,
-								 const char *origTblName,
-								 const char *origTypeName)
+find_composite_type_dependencies(Oid typeOid, char origRelkind,
+								 const char *origRelname)
 {
 	Relation	depRel;
 	ScanKeyData key[2];
@@ -3905,20 +3904,19 @@ find_composite_type_dependencies(Oid typeOid,
 
 		if (rel->rd_rel->relkind == RELKIND_RELATION)
 		{
-			if (origTblName)
-				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
-								origTblName,
-								RelationGetRelationName(rel),
-								NameStr(att->attname))));
+			const char *msg;
+			if (origRelkind == RELKIND_COMPOSITE_TYPE)
+				msg = gettext_noop("cannot alter type \"%s\" because column \"%s\".\"%s\" uses it");
+			else if (origRelkind == RELKIND_FOREIGN_TABLE)
+				msg = gettext_noop("cannot alter foreign table \"%s\" because column \"%s\".\"%s\" uses its rowtype");
 			else
-				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("cannot alter type \"%s\" because column \"%s\".\"%s\" uses it",
-								origTypeName,
-								RelationGetRelationName(rel),
-								NameStr(att->attname))));
+				msg = gettext_noop("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype");
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg(msg,
+							origRelname,
+							RelationGetRelationName(rel),
+							NameStr(att->attname))));
 		}
 		else if (OidIsValid(rel->rd_rel->reltype))
 		{
@@ -3927,7 +3925,7 @@ find_composite_type_dependencies(Oid typeOid,
 			 * recursively check for indirect dependencies via its rowtype.
 			 */
 			find_composite_type_dependencies(rel->rd_rel->reltype,
-											 origTblName, origTypeName);
+											 origRelkind, origRelname);
 		}
 
 		relation_close(rel, AccessShareLock);
@@ -3943,7 +3941,7 @@ find_composite_type_dependencies(Oid typeOid,
 	 */
 	arrayOid = get_array_type(typeOid);
 	if (OidIsValid(arrayOid))
-		find_composite_type_dependencies(arrayOid, origTblName, origTypeName);
+		find_composite_type_dependencies(arrayOid, origRelkind, origRelname);
 }
 
 
@@ -6444,14 +6442,15 @@ ATPrepAlterColumnType(List **wqueue,
 					 errmsg("ALTER TYPE USING is not supported on foreign tables")));
 	}
 
-	if (tab->relkind == RELKIND_COMPOSITE_TYPE)
+	if (tab->relkind == RELKIND_COMPOSITE_TYPE
+		|| tab->relkind == RELKIND_FOREIGN_TABLE)
 	{
 		/*
 		 * For composite types, do this check now.  Tables will check
 		 * it later when the table is being rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype,
-										 NULL,
+										 rel->rd_rel->relkind,
 										 RelationGetRelationName(rel));
 	}
 
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 2ecb238b9eb..619929ffe56 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -2183,7 +2183,7 @@ get_rels_with_domain(Oid domainOid, LOCKMODE lockmode)
 			 */
 			if (OidIsValid(rel->rd_rel->reltype))
 				find_composite_type_dependencies(rel->rd_rel->reltype,
-												 NULL,
+												 RELKIND_COMPOSITE_TYPE,
 												 format_type_be(domainOid));
 
 			/* Otherwise we can ignore views, composite types, etc */