From 6bf32f20150e9f6755584f2da418ee4f483d6e47 Mon Sep 17 00:00:00 2001
From: Tim Vaillancourt <tim@timvaillancourt.com>
Date: Wed, 6 Jul 2022 23:32:15 +0200
Subject: [PATCH] Ensure mysql rows responses are closed (#1132)

Co-authored-by: dm-2 <45519614+dm-2@users.noreply.github.com>
---
 .golangci.yml       |  2 ++
 go/logic/applier.go | 15 +++++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/.golangci.yml b/.golangci.yml
index 4a487bd..af04b55 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -9,4 +9,6 @@ linters:
   enable:
     - gosimple
     - govet
+    - rowserrcheck
+    - sqlclosecheck
     - unused
diff --git a/go/logic/applier.go b/go/logic/applier.go
index d6e5d5d..aa6dda3 100644
--- a/go/logic/applier.go
+++ b/go/logic/applier.go
@@ -382,10 +382,13 @@ func (this *Applier) ReadMigrationMinValues(uniqueKey *sql.UniqueKey) error {
 	if err != nil {
 		return err
 	}
+
 	rows, err := this.db.Query(query)
 	if err != nil {
 		return err
 	}
+	defer rows.Close()
+
 	for rows.Next() {
 		this.migrationContext.MigrationRangeMinValues = sql.NewColumnValues(uniqueKey.Len())
 		if err = rows.Scan(this.migrationContext.MigrationRangeMinValues.ValuesPointers...); err != nil {
@@ -394,8 +397,7 @@ func (this *Applier) ReadMigrationMinValues(uniqueKey *sql.UniqueKey) error {
 	}
 	this.migrationContext.Log.Infof("Migration min values: [%s]", this.migrationContext.MigrationRangeMinValues)
 
-	err = rows.Err()
-	return err
+	return rows.Err()
 }
 
 // ReadMigrationMaxValues returns the maximum values to be iterated on rowcopy
@@ -405,10 +407,13 @@ func (this *Applier) ReadMigrationMaxValues(uniqueKey *sql.UniqueKey) error {
 	if err != nil {
 		return err
 	}
+
 	rows, err := this.db.Query(query)
 	if err != nil {
 		return err
 	}
+	defer rows.Close()
+
 	for rows.Next() {
 		this.migrationContext.MigrationRangeMaxValues = sql.NewColumnValues(uniqueKey.Len())
 		if err = rows.Scan(this.migrationContext.MigrationRangeMaxValues.ValuesPointers...); err != nil {
@@ -417,8 +422,7 @@ func (this *Applier) ReadMigrationMaxValues(uniqueKey *sql.UniqueKey) error {
 	}
 	this.migrationContext.Log.Infof("Migration max values: [%s]", this.migrationContext.MigrationRangeMaxValues)
 
-	err = rows.Err()
-	return err
+	return rows.Err()
 }
 
 // ReadMigrationRangeValues reads min/max values that will be used for rowcopy.
@@ -479,10 +483,13 @@ func (this *Applier) CalculateNextIterationRangeEndValues() (hasFurtherRange boo
 		if err != nil {
 			return hasFurtherRange, err
 		}
+
 		rows, err := this.db.Query(query, explodedArgs...)
 		if err != nil {
 			return hasFurtherRange, err
 		}
+		defer rows.Close()
+
 		iterationRangeMaxValues := sql.NewColumnValues(this.migrationContext.UniqueKey.Len())
 		for rows.Next() {
 			if err = rows.Scan(iterationRangeMaxValues.ValuesPointers...); err != nil {