drop-trigger-if-exists.patch

commit a2de2b402247fded7feba90bf299e91ee14aacca
Author: Pavel Stehule <pavel.stehule@gooddata.com>
Date:   Thu Nov 28 08:39:43 2013 +0100

    initial

diff --git a/src/backend/catalog/objectaddress.c b/src/backend/catalog/objectaddress.c
index 9011190..234673f 100644
--- a/src/backend/catalog/objectaddress.c
+++ b/src/backend/catalog/objectaddress.c
@@ -942,26 +942,30 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 
 		/* Extract relation name and open relation. */
 		relname = list_truncate(list_copy(objname), nnames - 1);
-		relation = heap_openrv(makeRangeVarFromNameList(relname),
-							   AccessShareLock);
-		reloid = RelationGetRelid(relation);
+		relation = heap_openrv_extended(makeRangeVarFromNameList(relname),
+							   AccessShareLock,
+							   missing_ok);
+
+		reloid = (relation != NULL) ? RelationGetRelid(relation) : InvalidOid;
 
 		switch (objtype)
 		{
 			case OBJECT_RULE:
 				address.classId = RewriteRelationId;
-				address.objectId = get_rewrite_oid(reloid, depname, missing_ok);
+				address.objectId = OidIsValid(reloid) ?
+					get_rewrite_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
 			case OBJECT_TRIGGER:
 				address.classId = TriggerRelationId;
-				address.objectId = get_trigger_oid(reloid, depname, missing_ok);
+				address.objectId = OidIsValid(reloid) ?
+					get_trigger_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
 			case OBJECT_CONSTRAINT:
 				address.classId = ConstraintRelationId;
-				address.objectId =
-					get_relation_constraint_oid(reloid, depname, missing_ok);
+				address.objectId = OidIsValid(reloid) ?
+					get_relation_constraint_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
 			default:
@@ -975,7 +979,9 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 		/* Avoid relcache leak when object not found. */
 		if (!OidIsValid(address.objectId))
 		{
-			heap_close(relation, AccessShareLock);
+			if (relation != NULL)
+				heap_close(relation, AccessShareLock);
+
 			relation = NULL;	/* department of accident prevention */
 			return address;
 		}
diff --git a/src/backend/commands/dropcmds.c b/src/backend/commands/dropcmds.c
index b32ad3a..191aa17 100644
--- a/src/backend/commands/dropcmds.c
+++ b/src/backend/commands/dropcmds.c
@@ -23,6 +23,7 @@
 #include "catalog/pg_class.h"
 #include "catalog/pg_proc.h"
 #include "commands/defrem.h"
+#include "lib/stringinfo.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "parser/parse_type.h"
@@ -32,6 +33,12 @@
 static void does_not_exist_skipping(ObjectType objtype,
 						List *objname, List *objargs);
 
+static void prepare_notice_recheck_parent(const char *message,
+						List *objname,
+								const char **msg,
+								char **name,
+								char **args);
+
 /*
  * Drop one or more objects.
  *
@@ -125,6 +132,53 @@ RemoveObjects(DropStmt *stmt)
 }
 
 /*
+ * Prepare text of "does not exist, skipping" message for triggers and rules,
+ * where we check schema name first, then table name, and as last we raise
+ * message about missing object.
+ */
+static void
+prepare_notice_recheck_parent(const char *message, List *objname,
+							const char **msg,
+							char **name,
+							char **args)
+{
+	RangeVar	*rel;
+
+	rel = makeRangeVarFromNameList(list_truncate(list_copy(objname),
+							list_length(objname) - 1));
+
+	if (rel->schemaname != NULL && !OidIsValid(LookupNamespaceNoError(rel->schemaname)))
+	{
+		*msg = gettext_noop("schema \"%s\" does not exists, skipping");
+		*name = rel->schemaname;
+		*args = NULL;
+	}
+	else if (!OidIsValid(RangeVarGetRelid(rel, NoLock, true)))
+	{
+		*msg = gettext_noop("relation \"%s\" does not exists, skipping");
+		*name = rel->relname;
+		*args = NULL;
+	}
+	else
+	{
+		StringInfoData string;
+
+		*msg = message;
+		*name = strVal(llast(objname));
+
+		initStringInfo(&string);
+		if (rel->schemaname != NULL)
+		{
+			appendStringInfoString(&string, rel->schemaname);
+			appendStringInfoChar(&string, '.');
+		}
+		appendStringInfoString(&string, rel->relname);
+
+		*args = string.data;
+	}
+}
+
+/*
  * Generate a NOTICE stating that the named object was not found, and is
  * being skipped.  This is only relevant when "IF EXISTS" is used; otherwise,
  * get_object_address() will throw an ERROR.
@@ -201,20 +255,18 @@ does_not_exist_skipping(ObjectType objtype, List *objname, List *objargs)
 											(TypeName *) linitial(objargs)));
 			break;
 		case OBJECT_TRIGGER:
-			msg = gettext_noop("trigger \"%s\" for table \"%s\" does not exist, skipping");
-			name = strVal(llast(objname));
-			args = NameListToString(list_truncate(list_copy(objname),
-												  list_length(objname) - 1));
+			prepare_notice_recheck_parent("trigger \"%s\" for table \"%s\" does not exist, skipping",
+								    objname,
+									    &msg, &name, &args);
 			break;
 		case OBJECT_EVENT_TRIGGER:
 			msg = gettext_noop("event trigger \"%s\" does not exist, skipping");
 			name = NameListToString(objname);
 			break;
 		case OBJECT_RULE:
-			msg = gettext_noop("rule \"%s\" for relation \"%s\" does not exist, skipping");
-			name = strVal(llast(objname));
-			args = NameListToString(list_truncate(list_copy(objname),
-												  list_length(objname) - 1));
+			prepare_notice_recheck_parent("rule \"%s\" for relation \"%s\" does not exist, skipping",
+								    objname,
+									    &msg, &name, &args);
 			break;
 		case OBJECT_FDW:
 			msg = gettext_noop("foreign-data wrapper \"%s\" does not exist, skipping");
diff --git a/src/test/regress/expected/drop_if_exists.out b/src/test/regress/expected/drop_if_exists.out
index 8599401..663b438 100644
--- a/src/test/regress/expected/drop_if_exists.out
+++ b/src/test/regress/expected/drop_if_exists.out
@@ -173,7 +173,11 @@ NOTICE:  trigger "test_trigger_exists" for table "test_exists" does not exist, s
 DROP TRIGGER test_trigger_exists ON no_such_table;
 ERROR:  relation "no_such_table" does not exist
 DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_table;
-ERROR:  relation "no_such_table" does not exist
+NOTICE:  relation "no_such_table" does not exists, skipping
+DROP TRIGGER test_trigger_exists ON no_such_schema.no_such_table;
+ERROR:  schema "no_such_schema" does not exist
+DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_schema.no_such_table;
+NOTICE:  schema "no_such_schema" does not exists, skipping
 CREATE TRIGGER test_trigger_exists
     BEFORE UPDATE ON test_exists
     FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
@@ -186,7 +190,11 @@ NOTICE:  rule "test_rule_exists" for relation "test_exists" does not exist, skip
 DROP RULE test_rule_exists ON no_such_table;
 ERROR:  relation "no_such_table" does not exist
 DROP RULE IF EXISTS test_rule_exists ON no_such_table;
-ERROR:  relation "no_such_table" does not exist
+NOTICE:  relation "no_such_table" does not exists, skipping
+DROP RULE test_rule_exists ON no_such_schema.no_such_table;
+ERROR:  schema "no_such_schema" does not exist
+DROP RULE IF EXISTS test_rule_exists ON no_such_schema.no_such_table;
+NOTICE:  schema "no_such_schema" does not exists, skipping
 CREATE RULE test_rule_exists AS ON INSERT TO test_exists
     DO INSTEAD
     INSERT INTO test_exists VALUES (NEW.a, NEW.b || NEW.a::text);
diff --git a/src/test/regress/sql/drop_if_exists.sql b/src/test/regress/sql/drop_if_exists.sql
index 6330566..8977357 100644
--- a/src/test/regress/sql/drop_if_exists.sql
+++ b/src/test/regress/sql/drop_if_exists.sql
@@ -182,6 +182,9 @@ DROP TRIGGER IF EXISTS test_trigger_exists ON test_exists;
 DROP TRIGGER test_trigger_exists ON no_such_table;
 DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_table;
 
+DROP TRIGGER test_trigger_exists ON no_such_schema.no_such_table;
+DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_schema.no_such_table;
+
 CREATE TRIGGER test_trigger_exists
     BEFORE UPDATE ON test_exists
     FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
@@ -194,6 +197,9 @@ DROP RULE IF EXISTS test_rule_exists ON test_exists;
 DROP RULE test_rule_exists ON no_such_table;
 DROP RULE IF EXISTS test_rule_exists ON no_such_table;
 
+DROP RULE test_rule_exists ON no_such_schema.no_such_table;
+DROP RULE IF EXISTS test_rule_exists ON no_such_schema.no_such_table;
+
 CREATE RULE test_rule_exists AS ON INSERT TO test_exists
     DO INSTEAD
     INSERT INTO test_exists VALUES (NEW.a, NEW.b || NEW.a::text);