From 5dee75553d5d0d4becaf330c1ff5d54bd42f6b14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Espino?= <jespinog@gmail.com>
Date: Thu, 11 Apr 2019 08:57:25 +0200
Subject: [PATCH] MM-15006: Returning informative errors on config validation
 (#10585)

* MM-15006: Returning informative errors on config validation

* Adding new unit test verifying the validation and correct response
---
 api4/config.go      |  8 +++++++-
 api4/config_test.go | 10 ++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/api4/config.go b/api4/config.go
index 815a3da3340..0be330cb948 100644
--- a/api4/config.go
+++ b/api4/config.go
@@ -95,7 +95,13 @@ func updateConfig(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	err := c.App.SaveConfig(cfg, true)
+	err := cfg.IsValid()
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	err = c.App.SaveConfig(cfg, true)
 	if err != nil {
 		c.Err = err
 		return
diff --git a/api4/config_test.go b/api4/config_test.go
index 89040c3c3a1..f2d2373ad50 100644
--- a/api4/config_test.go
+++ b/api4/config_test.go
@@ -111,6 +111,16 @@ func TestUpdateConfig(t *testing.T) {
 
 	require.Equal(t, SiteName, cfg.TeamSettings.SiteName, "It should update the SiteName")
 
+	t.Run("Should fail with validation error if invalid config setting is passed", func(t *testing.T) {
+		//Revert the change
+		badcfg := cfg.Clone()
+		badcfg.PasswordSettings.MinimumLength = model.NewInt(4)
+		badcfg.PasswordSettings.MinimumLength = model.NewInt(4)
+		_, resp = th.SystemAdminClient.UpdateConfig(badcfg)
+		CheckBadRequestStatus(t, resp)
+		CheckErrorMessage(t, resp, "model.config.is_valid.password_length.app_error")
+	})
+
 	t.Run("Should not be able to modify PluginSettings.EnableUploads", func(t *testing.T) {
 		oldEnableUploads := *th.App.Config().PluginSettings.EnableUploads
 		*cfg.PluginSettings.EnableUploads = !oldEnableUploads