From eb7dd8e377c19524788e3532214f10c4cd354267 Mon Sep 17 00:00:00 2001
From: Josh Myers <joshuajmyers@gmail.com>
Date: Thu, 17 Jun 2021 07:33:36 +0100
Subject: [PATCH] Dashboard: protect against missing overrides section (#35577)

* Protect against missing overrides section

We are using grafonnet-lib to generate dashboards. These dashboards do
not contain any `override` keys in `fieldConfig` by default and that is
causing this DashboardMigrator script to blow up when trying to import
the dashboards, see [1]. In Grafana v7, an empty overrides is
automatically added but using grafonnet-lib, it isn't possible to set an
empty overrides attribute e.g. [2] requires matcher/properties to be
set. Setting to null ends up giving me [3], which causes the panel to
not be displayed.

[1]
```
initDashboard.ts:137 TypeError: t.overrides is not iterable
    at v.w (DashboardMigrator.ts:960)
    at v.updateSchema (DashboardMigrator.ts:672)
    at D.updateSchema (DashboardModel.ts:993)
    at new D (DashboardModel.ts:156)
    at initDashboard.ts:134
```

[2]
https://github.com/grafana/grafonnet-lib/blob/master/grafonnet/stat_panel.libsonnet#L150-L164

[3]
```
"fieldConfig": {
   "defaults": {
      "links": [ ],
      "mappings": [ ],
      "thresholds": {
         "mode": "absolute",
         "steps": [
            {
               "color": "red",
               "value": 0
            },
            {
               "color": "orange",
               "value": 1
            },
            {
               "color": "green",
               "value": 3
            }
         ]
      },
      "unit": "none"
   },
   "overrides": [
      { }
   ]
},
```

* Update public/app/features/dashboard/state/DashboardMigrator.ts

Co-authored-by: Marcus Andersson <systemvetaren@gmail.com>
---
 .../app/features/dashboard/state/DashboardMigrator.ts | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/public/app/features/dashboard/state/DashboardMigrator.ts b/public/app/features/dashboard/state/DashboardMigrator.ts
index 7c0acd29ff3..7a09a5e357b 100644
--- a/public/app/features/dashboard/state/DashboardMigrator.ts
+++ b/public/app/features/dashboard/state/DashboardMigrator.ts
@@ -957,10 +957,13 @@ function upgradeValueMappingsForPanel(panel: PanelModel) {
 
   fieldConfig.defaults.mappings = upgradeValueMappings(fieldConfig.defaults.mappings, fieldConfig.defaults.thresholds);
 
-  for (const override of fieldConfig.overrides) {
-    for (const prop of override.properties) {
-      if (prop.id === 'mappings') {
-        prop.value = upgradeValueMappings(prop.value);
+  // Protect against no overrides
+  if (Array.isArray(fieldConfig.overrides)) {
+    for (const override of fieldConfig.overrides) {
+      for (const prop of override.properties) {
+        if (prop.id === 'mappings') {
+          prop.value = upgradeValueMappings(prop.value);
+        }
       }
     }
   }