MM-13312 Prevent clobbering of new fields by old plugins. (#10087)

* Prevent clobbering of new fields by old plugins.

* Apply suggestions from code review

Spelling and copy paste error.

Co-Authored-By: crspeller <crspeller@gmail.com>

plugin/client_rpc.go

@@ -407,7 +407,7 @@ func (g *hooksRPCClient) FileWillBeUploaded(c *Context, info *model.FileInfo, fi
 	}()
 
 	_args := &Z_FileWillBeUploadedArgs{c, info, uploadedFileStreamId, replacementFileStreamId}
-	_returns := &Z_FileWillBeUploadedReturns{}
+	_returns := &Z_FileWillBeUploadedReturns{A: _args.B}
 	if g.implemented[FileWillBeUploadedId] {
 		if err := g.client.Call("Plugin.FileWillBeUploaded", _args, _returns); err != nil {
 			g.log.Error("RPC call FileWillBeUploaded to plugin failed.", mlog.Err(err))
@@ -443,3 +443,84 @@ func (s *hooksRPCServer) FileWillBeUploaded(args *Z_FileWillBeUploadedArgs, retu
 	}
 	return nil
 }
+
+// MessageWillBePosted is in this file because of the difficulty of identifiying which fields need special behaviour.
+// The special behaviour needed is decoding the returned post into the original one to avoid the unintentional removal
+// of fields by older plugins.
+func init() {
+	hookNameToId["MessageWillBePosted"] = MessageWillBePostedId
+}
+
+type Z_MessageWillBePostedArgs struct {
+	A *Context
+	B *model.Post
+}
+
+type Z_MessageWillBePostedReturns struct {
+	A *model.Post
+	B string
+}
+
+func (g *hooksRPCClient) MessageWillBePosted(c *Context, post *model.Post) (*model.Post, string) {
+	_args := &Z_MessageWillBePostedArgs{c, post}
+	_returns := &Z_MessageWillBePostedReturns{A: _args.B}
+	if g.implemented[MessageWillBePostedId] {
+		if err := g.client.Call("Plugin.MessageWillBePosted", _args, _returns); err != nil {
+			g.log.Error("RPC call MessageWillBePosted to plugin failed.", mlog.Err(err))
+		}
+	}
+	return _returns.A, _returns.B
+}
+
+func (s *hooksRPCServer) MessageWillBePosted(args *Z_MessageWillBePostedArgs, returns *Z_MessageWillBePostedReturns) error {
+	if hook, ok := s.impl.(interface {
+		MessageWillBePosted(c *Context, post *model.Post) (*model.Post, string)
+	}); ok {
+		returns.A, returns.B = hook.MessageWillBePosted(args.A, args.B)
+
+	} else {
+		return encodableError(fmt.Errorf("Hook MessageWillBePosted called but not implemented."))
+	}
+	return nil
+}
+
+// MessageWillBeUpdated is in this file because of the difficulty of identifiying which fields need special behaviour.
+// The special behavour needed is decoding the returned post into the original one to avoid the unintentional removal
+// of fields by older plugins.
+func init() {
+	hookNameToId["MessageWillBeUpdated"] = MessageWillBeUpdatedId
+}
+
+type Z_MessageWillBeUpdatedArgs struct {
+	A *Context
+	B *model.Post
+	C *model.Post
+}
+
+type Z_MessageWillBeUpdatedReturns struct {
+	A *model.Post
+	B string
+}
+
+func (g *hooksRPCClient) MessageWillBeUpdated(c *Context, newPost, oldPost *model.Post) (*model.Post, string) {
+	_args := &Z_MessageWillBeUpdatedArgs{c, newPost, oldPost}
+	_returns := &Z_MessageWillBeUpdatedReturns{A: _args.B}
+	if g.implemented[MessageWillBeUpdatedId] {
+		if err := g.client.Call("Plugin.MessageWillBeUpdated", _args, _returns); err != nil {
+			g.log.Error("RPC call MessageWillBeUpdated to plugin failed.", mlog.Err(err))
+		}
+	}
+	return _returns.A, _returns.B
+}
+
+func (s *hooksRPCServer) MessageWillBeUpdated(args *Z_MessageWillBeUpdatedArgs, returns *Z_MessageWillBeUpdatedReturns) error {
+	if hook, ok := s.impl.(interface {
+		MessageWillBeUpdated(c *Context, newPost, oldPost *model.Post) (*model.Post, string)
+	}); ok {
+		returns.A, returns.B = hook.MessageWillBeUpdated(args.A, args.B, args.C)
+
+	} else {
+		return encodableError(fmt.Errorf("Hook MessageWillBeUpdated called but not implemented."))
+	}
+	return nil
+}

plugin/client_rpc_generated.go

@@ -119,81 +119,6 @@ func (s *hooksRPCServer) ExecuteCommand(args *Z_ExecuteCommandArgs, returns *Z_E
 	return nil
 }
 
-func init() {
-	hookNameToId["MessageWillBePosted"] = MessageWillBePostedId
-}
-
-type Z_MessageWillBePostedArgs struct {
-	A *Context
-	B *model.Post
-}
-
-type Z_MessageWillBePostedReturns struct {
-	A *model.Post
-	B string
-}
-
-func (g *hooksRPCClient) MessageWillBePosted(c *Context, post *model.Post) (*model.Post, string) {
-	_args := &Z_MessageWillBePostedArgs{c, post}
-	_returns := &Z_MessageWillBePostedReturns{}
-	if g.implemented[MessageWillBePostedId] {
-		if err := g.client.Call("Plugin.MessageWillBePosted", _args, _returns); err != nil {
-			g.log.Error("RPC call MessageWillBePosted to plugin failed.", mlog.Err(err))
-		}
-	}
-	return _returns.A, _returns.B
-}
-
-func (s *hooksRPCServer) MessageWillBePosted(args *Z_MessageWillBePostedArgs, returns *Z_MessageWillBePostedReturns) error {
-	if hook, ok := s.impl.(interface {
-		MessageWillBePosted(c *Context, post *model.Post) (*model.Post, string)
-	}); ok {
-		returns.A, returns.B = hook.MessageWillBePosted(args.A, args.B)
-
-	} else {
-		return encodableError(fmt.Errorf("Hook MessageWillBePosted called but not implemented."))
-	}
-	return nil
-}
-
-func init() {
-	hookNameToId["MessageWillBeUpdated"] = MessageWillBeUpdatedId
-}
-
-type Z_MessageWillBeUpdatedArgs struct {
-	A *Context
-	B *model.Post
-	C *model.Post
-}
-
-type Z_MessageWillBeUpdatedReturns struct {
-	A *model.Post
-	B string
-}
-
-func (g *hooksRPCClient) MessageWillBeUpdated(c *Context, newPost, oldPost *model.Post) (*model.Post, string) {
-	_args := &Z_MessageWillBeUpdatedArgs{c, newPost, oldPost}
-	_returns := &Z_MessageWillBeUpdatedReturns{}
-	if g.implemented[MessageWillBeUpdatedId] {
-		if err := g.client.Call("Plugin.MessageWillBeUpdated", _args, _returns); err != nil {
-			g.log.Error("RPC call MessageWillBeUpdated to plugin failed.", mlog.Err(err))
-		}
-	}
-	return _returns.A, _returns.B
-}
-
-func (s *hooksRPCServer) MessageWillBeUpdated(args *Z_MessageWillBeUpdatedArgs, returns *Z_MessageWillBeUpdatedReturns) error {
-	if hook, ok := s.impl.(interface {
-		MessageWillBeUpdated(c *Context, newPost, oldPost *model.Post) (*model.Post, string)
-	}); ok {
-		returns.A, returns.B = hook.MessageWillBeUpdated(args.A, args.B, args.C)
-
-	} else {
-		return encodableError(fmt.Errorf("Hook MessageWillBeUpdated called but not implemented."))
-	}
-	return nil
-}
-
 func init() {
 	hookNameToId["MessageHasBeenPosted"] = MessageHasBeenPostedId
 }

plugin/interface_generator/main.go

@@ -397,6 +397,8 @@ func removeExcluded(info *PluginInterfaceInfo) *PluginInterfaceInfo {
 			"LoadPluginConfiguration",
 			"ServeHTTP",
 			"FileWillBeUploaded",
+			"MessageWillBePosted",
+			"MessageWillBeUpdated",
 		}
 		for _, exclusion := range excluded {
 			if exclusion == item {