Fix ALTER TABLE code to update domain constraints when needed.

It's possible for dropping a column, or altering its type, to require
changes in domain CHECK constraint expressions; but the code was
previously only expecting to find dependent table CHECK constraints.
Make the necessary adjustments.

This is a fairly old oversight, but it's a lot easier to encounter
the problem in the context of domains over composite types than it
was before.  Given the lack of field complaints, I'm not going to
bother with a back-patch, though I'd be willing to reconsider that
decision if someone does complain.

Patch by me, reviewed by Michael Paquier

Discussion: https://postgr.es/m/30656.1509128130@sss.pgh.pa.us

1 files changed, 58 insertions, 9 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index b1e70a0d19e..cc6cec7877d 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -460,6 +460,7 @@ static char *generate_function_name(Oid funcid, int nargs,
 					   bool has_variadic, bool *use_variadic_p,
 					   ParseExprKind special_exprkind);
 static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
+static char *generate_qualified_type_name(Oid typid);
 static text *string_to_text(char *str);
 static char *flatten_reloptions(Oid relid);
 
@@ -1867,15 +1868,27 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 
 	if (fullCommand)
 	{
-		/*
-		 * Currently, callers want ALTER TABLE (without ONLY) for CHECK
-		 * constraints, and other types of constraints don't inherit anyway so
-		 * it doesn't matter whether we say ONLY or not.  Someday we might
-		 * need to let callers specify whether to put ONLY in the command.
-		 */
-		appendStringInfo(&buf, "ALTER TABLE %s ADD CONSTRAINT %s ",
-						 generate_qualified_relation_name(conForm->conrelid),
-						 quote_identifier(NameStr(conForm->conname)));
+		if (OidIsValid(conForm->conrelid))
+		{
+			/*
+			 * Currently, callers want ALTER TABLE (without ONLY) for CHECK
+			 * constraints, and other types of constraints don't inherit
+			 * anyway so it doesn't matter whether we say ONLY or not. Someday
+			 * we might need to let callers specify whether to put ONLY in the
+			 * command.
+			 */
+			appendStringInfo(&buf, "ALTER TABLE %s ADD CONSTRAINT %s ",
+							 generate_qualified_relation_name(conForm->conrelid),
+							 quote_identifier(NameStr(conForm->conname)));
+		}
+		else
+		{
+			/* Must be a domain constraint */
+			Assert(OidIsValid(conForm->contypid));
+			appendStringInfo(&buf, "ALTER DOMAIN %s ADD CONSTRAINT %s ",
+							 generate_qualified_type_name(conForm->contypid),
+							 quote_identifier(NameStr(conForm->conname)));
+		}
 	}
 
 	switch (conForm->contype)
@@ -10779,6 +10792,42 @@ generate_operator_name(Oid operid, Oid arg1, Oid arg2)
 }
 
 /*
+ * generate_qualified_type_name
+ *		Compute the name to display for a type specified by OID
+ *
+ * This is different from format_type_be() in that we unconditionally
+ * schema-qualify the name.  That also means no special syntax for
+ * SQL-standard type names ... although in current usage, this should
+ * only get used for domains, so such cases wouldn't occur anyway.
+ */
+static char *
+generate_qualified_type_name(Oid typid)
+{
+	HeapTuple	tp;
+	Form_pg_type typtup;
+	char	   *typname;
+	char	   *nspname;
+	char	   *result;
+
+	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for type %u", typid);
+	typtup = (Form_pg_type) GETSTRUCT(tp);
+	typname = NameStr(typtup->typname);
+
+	nspname = get_namespace_name(typtup->typnamespace);
+	if (!nspname)
+		elog(ERROR, "cache lookup failed for namespace %u",
+			 typtup->typnamespace);
+
+	result = quote_qualified_identifier(nspname, typname);
+
+	ReleaseSysCache(tp);
+
+	return result;
+}
+
+/*
  * generate_collation_name
  *		Compute the name to display for a collation specified by OID
  *