From 19460e3c9f49e4c3690e7c6584c2c3c699a95be3 Mon Sep 17 00:00:00 2001
From: notzippy <notzippy@gmail.com>
Date: Sat, 5 Mar 2022 08:03:12 -0800
Subject: [PATCH] Added write lock mechanizim around controller reuse closes
 1547

---
 controller.go             | 6 ++++++
 model/revel_controller.go | 7 ++++++-
 revel.go                  | 2 ++
 server.go                 | 2 ++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/controller.go b/controller.go
index 2f4235c7..945c56db 100644
--- a/controller.go
+++ b/controller.go
@@ -410,15 +410,21 @@ func (c *Controller) SetTypeAction(controllerName, methodName string, typeOfCont
 	}
 
 	if RevelConfig.Controller.Reuse {
+		RevelConfig.Controller.CacheMapLocked.RLock()
 		if _, ok := RevelConfig.Controller.CachedMap[c.Name]; !ok {
 			// Create a new stack for this controller
 			localType := c.Type.Type
+			RevelConfig.Controller.CacheMapLocked.RUnlock()
+			RevelConfig.Controller.CacheMapLocked.Lock()
+			defer RevelConfig.Controller.CacheMapLocked.Unlock()
 			RevelConfig.Controller.CachedMap[c.Name] = utils.NewStackLock(
 				RevelConfig.Controller.CachedStackSize,
 				RevelConfig.Controller.CachedStackMaxSize,
 				func() interface{} {
 					return reflect.New(localType).Interface()
 				})
+		} else {
+			defer RevelConfig.Controller.CacheMapLocked.RUnlock()
 		}
 		// Instantiate the controller.
 		c.AppController = RevelConfig.Controller.CachedMap[c.Name].Pop()
diff --git a/model/revel_controller.go b/model/revel_controller.go
index e3dcc435..3b3cc299 100644
--- a/model/revel_controller.go
+++ b/model/revel_controller.go
@@ -1,11 +1,16 @@
 package model
 
-import "github.com/revel/revel/utils"
+import (
+	"sync"
+
+	"github.com/revel/revel/utils"
+)
 
 type RevelController struct {
 	Reuse              bool                              // True if the controllers are reused Set via revel.controller.reuse
 	Stack              *utils.SimpleLockStack            // size set by revel.controller.stack,  revel.controller.maxstack
 	CachedMap          map[string]*utils.SimpleLockStack // The map of reusable controllers
+	CacheMapLocked     *sync.RWMutex                     // A locking mechanizim to prevent concurrent writes to the cache
 	CachedStackSize    int                               // The default size of each stack in CachedMap Set via revel.cache.controller.stack
 	CachedStackMaxSize int                               // The max size of each stack in CachedMap Set via revel.cache.controller.maxstack
 }
diff --git a/revel.go b/revel.go
index d328fec9..36979889 100644
--- a/revel.go
+++ b/revel.go
@@ -229,6 +229,8 @@ func updateLog(inputmode string) (returnMode string) {
 				packagePathMap[k] = v.(string)
 			}
 		}
+	} else {
+		RevelLog.Warn("Failed to unpack json file", "error", err, "Json", inputmode)
 	}
 
 	var newContext *config.Context
diff --git a/server.go b/server.go
index b9eb2d8c..f7cc6cb5 100644
--- a/server.go
+++ b/server.go
@@ -9,6 +9,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/revel/revel/session"
 	"github.com/revel/revel/utils"
@@ -146,6 +147,7 @@ func initControllerStack() {
 		RevelConfig.Controller.CachedStackSize = Config.IntDefault("revel.cache.controller.stack", 10)
 		RevelConfig.Controller.CachedStackMaxSize = Config.IntDefault("revel.cache.controller.maxstack", 100)
 		RevelConfig.Controller.CachedMap = map[string]*utils.SimpleLockStack{}
+		RevelConfig.Controller.CacheMapLocked = &sync.RWMutex{}
 	}
 }