neovim

commit 4fe51dfdae84f139bb92f8517aff914c4adb052c
parent 1685c44dd463217db01643a97163420ed9f5b177
Author: glepnir <glephunter@gmail.com>
Date:   Wed, 23 Jul 2025 08:40:24 +0800

fix(iter): ArrayIter:last returns nil when filtered to empty #34697

Problem: After filtering out all elements, ArrayIter:last still returns a stale element.
Solution: Add check for self._head == self._tail and return nil early.

Fix #34696
Diffstat:
M
runtime/lua/vim/iter.lua
 | 
3
+++
M
test/functional/lua/iter_spec.lua
 | 
9
+++++++++

2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/runtime/lua/vim/iter.lua b/runtime/lua/vim/iter.lua
@@ -1010,6 +1010,9 @@ end
 
 ---@private
 function ArrayIter:last()
+  if self._head >= self._tail then
+    return nil
+  end
   local inc = self._head < self._tail and 1 or -1
   local v = self._table[self._tail - inc]
   self._head = self._tail
diff --git a/test/functional/lua/iter_spec.lua b/test/functional/lua/iter_spec.lua
@@ -405,6 +405,15 @@ describe('vim.iter', function()
     local s = 'abcdefghijklmnopqrstuvwxyz'
     eq('z', vim.iter(vim.split(s, '')):last())
     eq('z', vim.iter(vim.gsplit(s, '')):last())
+    eq(
+      nil,
+      vim
+        .iter({ 1, 2, 3, 4, 5 })
+        :filter(function()
+          return false
+        end)
+        :last()
+    )
   end)
 
   it('enumerate()', function()