Merge pull request #3115 from dolthub/fulghum/info_schema_triggers

Bug fix: correctly parse/resolve trigger definitions across multiple databases

Author: fulghum

enginetest/queries/information_schema_queries.go

@@ -830,6 +830,40 @@ var SkippedInfoSchemaQueries = []QueryTest{
 }
 
 var InfoSchemaScripts = []ScriptTest{
+	{
+		Name: "List triggers across multiple databases",
+		SetUpScript: []string{
+			"CREATE DATABASE db1;",
+			"CREATE DATABASE db2;",
+			"USE db1;",
+			"CREATE TABLE main1(pk int primary key, c1 varchar(100));",
+			"CREATE TABLE main2(pk int primary key);",
+			"CREATE TRIGGER before_insert_main1 BEFORE INSERT ON main1 FOR EACH ROW BEGIN DECLARE row_count INT; SELECT COUNT(*) INTO row_count FROM main2; IF row_count > 0 THEN SET NEW.c1 = 'has data'; ELSE SET NEW.c1 = 'empty'; END IF; END",
+			"USE db2;",
+			"CREATE TABLE b1(pk int primary key, c1 varchar(100));",
+			"CREATE TABLE b2(pk int primary key);",
+			"CREATE TRIGGER before_insert_b1 BEFORE INSERT ON b1 FOR EACH ROW BEGIN DECLARE row_count INT; SELECT COUNT(*) INTO row_count FROM b2; IF row_count > 0 THEN SET NEW.c1 = 'has data'; ELSE SET NEW.c1 = 'empty'; END IF; END",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:    "USE db1;",
+				Expected: []sql.Row{},
+			},
+			{
+				Query:    "SELECT database();",
+				Expected: []sql.Row{{"db1"}},
+			},
+			{
+				Query:    "SELECT trigger_catalog, trigger_schema, trigger_name FROM information_schema.triggers;",
+				Expected: []sql.Row{{"def", "db1", "before_insert_main1"}, {"def", "db2", "before_insert_b1"}},
+			},
+			{
+				// Ensure the current database is still db1
+				Query:    "SELECT database();",
+				Expected: []sql.Row{{"db1"}},
+			},
+		},
+	},
 	{
 		Name: "foreign key that references dropped table",
 		SetUpScript: []string{

sql/information_schema/information_schema.go

@@ -1937,8 +1937,16 @@ func triggersRowIter(ctx *Context, c Catalog) (RowIter, error) {
 				continue
 			}
 
+			// Capture the current database, so that we can ensure it gets set back to this value
+			// after we adjust it to parse each database's triggers.
+			originalDatabase := ctx.GetCurrentDatabase()
+			defer ctx.SetCurrentDatabase(originalDatabase)
+
 			var triggerPlans []*plan.CreateTrigger
 			for _, trigger := range triggers {
+				// Because we have to parse/resolve the CREATE TRIGGER statement again, we update the
+				// session's current database so that ParseWithOptions can correctly resolve references.
+				ctx.SetCurrentDatabase(db.Database.Name())
 				triggerSqlMode := NewSqlModeFromString(trigger.SqlMode)
 				// TODO: figure out how auth works in this case
 				parsedTrigger, _, err := planbuilder.ParseWithOptions(ctx, c, trigger.CreateStatement, triggerSqlMode.ParserOptions())
@@ -1954,6 +1962,9 @@ func triggersRowIter(ctx *Context, c Catalog) (RowIter, error) {
 				triggerPlans = append(triggerPlans, triggerPlan)
 			}
 
+			// Set the context back to the original database, since we changed it to parse each database's triggers
+			ctx.SetCurrentDatabase(originalDatabase)
+
 			beforeTriggers, afterTriggers := plan.OrderTriggers(triggerPlans)
 			var beforeDelete []*plan.CreateTrigger
 			var beforeInsert []*plan.CreateTrigger