Rescue for SUPPORTED_CHAINS env var parsing

.dialyzer-ignore

@@ -12,4 +12,4 @@ apps/explorer/lib/explorer/smart_contract/publisher_worker.ex:6: The pattern 'fa
 apps/explorer/lib/explorer/smart_contract/publisher_worker.ex:6: The test 5 == 'infinity' can never evaluate to 'true'
 lib/block_scout_web/router.ex:1
 lib/phoenix/router.ex:324
-lib/block_scout_web/views/layout_view.ex:142
+lib/block_scout_web/views/layout_view.ex:143

CHANGELOG.md

@@ -7,6 +7,7 @@
 - [#2834](https://github.com/poanetwork/blockscout/pull/2834) - always redirect to checksummed hash
 
 ### Fixes
+- [#3027](https://github.com/poanetwork/blockscout/pull/3027) - Rescue for SUPPORTED_CHAINS env var parsing
 - [#3025](https://github.com/poanetwork/blockscout/pull/3025) - Fix splitting of indexer/web components setup
 - [#3024](https://github.com/poanetwork/blockscout/pull/3024) - Fix pool size default value in config
 - [#3021](https://github.com/poanetwork/blockscout/pull/3021), [#3022](https://github.com/poanetwork/blockscout/pull/3022) - Refine dev/test config

apps/block_scout_web/lib/block_scout_web/views/layout_view.ex

@@ -137,9 +137,14 @@ defmodule BlockScoutWeb.LayoutView do
   def other_networks do
     get_other_networks =
       if Application.get_env(:block_scout_web, :other_networks) do
-        :block_scout_web
-        |> Application.get_env(:other_networks)
-        |> Parser.parse!(%{keys: :atoms!})
+        try do
+          :block_scout_web
+          |> Application.get_env(:other_networks)
+          |> Parser.parse!(%{keys: :atoms!})
+        rescue
+          _ ->
+            []
+        end
       else
         @default_other_networks
       end

apps/block_scout_web/test/block_scout_web/views/layout_view_test.exs

@@ -115,6 +115,12 @@ defmodule BlockScoutWeb.LayoutViewTest do
                }
              ]
     end
+
+    test "get empty networks list if SUPPORTED_CHAINS is not parsed" do
+      Application.put_env(:block_scout_web, :other_networks, "not a valid json")
+
+      assert LayoutView.other_networks() == []
+    end
   end
 
   describe "main_nets/1" do