From 7a856be6e49bc72fa776592e37dd1573550963f3 Mon Sep 17 00:00:00 2001
From: Francesco Abbate <francesco.bbt@gmail.com>
Date: Mon, 16 Nov 2020 18:12:31 +0100
Subject: [PATCH] Fix error when opening the first document if project view was
 active

---
 data/core/rootview.lua | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/data/core/rootview.lua b/data/core/rootview.lua
index 389525f6..8bcc03da 100644
--- a/data/core/rootview.lua
+++ b/data/core/rootview.lua
@@ -396,14 +396,33 @@ function RootView:get_active_node()
   return self.root_node:get_node_for_view(core.active_view)
 end
 
+-- Get un unlocked node with at least one view.
+local function get_node_unlocked(node)
+  if not node.locked and #node.views > 0 then
+    return node
+  end
+  if node.type ~= "leaf" then
+    local a = get_node_unlocked(node.a)
+    if a then return a end
+    return get_node_unlocked(node.b)
+  end
+end
+
+function RootView:get_document_view()
+  local node = get_node_unlocked(self.root_node)
+  if node then
+    return node.views[1]
+  end
+end
 
 function RootView:open_doc(doc)
   local node = self:get_active_node()
-  if node.locked and core.last_active_view then
-    core.set_active_view(core.last_active_view)
+  if node.locked then
+    local default_view = self:get_document_view()
+    assert(default_view, "Cannot find an unlocked node to open the document.")
+    core.set_active_view(default_view)
     node = self:get_active_node()
   end
-  assert(not node.locked, "Cannot open doc on locked node")
   for i, view in ipairs(node.views) do
     if view.doc == doc then
       node:set_active_view(node.views[i])