1 files changed, 38 insertions, 1 deletions

diff --git a/test/functional/eval/let_spec.lua b/test/functional/eval/let_spec.lua
index 1bd3405698..0cbf40137e 100644
--- a/test/functional/eval/let_spec.lua
+++ b/test/functional/eval/let_spec.lua
@@ -2,13 +2,16 @@ local helpers = require('test.functional.helpers')(after_each)
 
 local eq = helpers.eq
 local clear = helpers.clear
+local command = helpers.command
+local eval = helpers.eval
 local meths = helpers.meths
 local redir_exec = helpers.redir_exec
 local source = helpers.source
+local nvim_dir = helpers.nvim_dir
 
 before_each(clear)
 
-describe(':let command', function()
+describe(':let', function()
   it('correctly lists variables with curly-braces', function()
     meths.set_var('v', {0})
     eq('\nv                     [0]', redir_exec('let {"v"}'))
@@ -42,4 +45,38 @@ describe(':let command', function()
       call feedkeys(":\e:echo l1 l3\n:echo 42\n:cq\n", "t")
     ]=])
   end)
+
+  it("multibyte env var #8398 #9267", function()
+    command("let $NVIM_TEST = 'AìaB'")
+    eq('AìaB', eval('$NVIM_TEST'))
+    command("let $NVIM_TEST = 'AaあB'")
+    eq('AaあB', eval('$NVIM_TEST'))
+    local mbyte = [[\p* .ม .ม .ม .ม่ .ม่ .ม่ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹֻ ֹֻ ֹֻ
+                    .ֹֻ .ֹֻ .ֹֻ ֹֻ ֹֻ ֹֻ .ֹֻ .ֹֻ .ֹֻ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹֻ ֹֻ
+                    .ֹֻ .ֹֻ .ֹֻ a a a ca ca ca à à à]]
+    command("let $NVIM_TEST = '"..mbyte.."'")
+    eq(mbyte, eval('$NVIM_TEST'))
+  end)
+
+  it("multibyte env var to child process #8398 #9267",  function()
+    if (not helpers.iswin()) and require('test.helpers').isCI() then
+      -- Fails on non-Windows CI. Buffering/timing issue?
+      pending('fails on unix CI', function() end)
+    end
+    local cmd_get_child_env = "let g:env_from_child = system(['"..nvim_dir.."/printenv-test', 'NVIM_TEST'])"
+    command("let $NVIM_TEST = 'AìaB'")
+    command(cmd_get_child_env)
+    eq(eval('$NVIM_TEST'), eval('g:env_from_child'))
+
+    command("let $NVIM_TEST = 'AaあB'")
+    command(cmd_get_child_env)
+    eq(eval('$NVIM_TEST'), eval('g:env_from_child'))
+
+    local mbyte = [[\p* .ม .ม .ม .ม่ .ม่ .ม่ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹֻ ֹֻ ֹֻ
+                    .ֹֻ .ֹֻ .ֹֻ ֹֻ ֹֻ ֹֻ .ֹֻ .ֹֻ .ֹֻ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹ ֹ ֹ .ֹ .ֹ .ֹ ֹֻ ֹֻ
+                    .ֹֻ .ֹֻ .ֹֻ a a a ca ca ca à à à]]
+    command("let $NVIM_TEST = '"..mbyte.."'")
+    command(cmd_get_child_env)
+    eq(eval('$NVIM_TEST'), eval('g:env_from_child'))
+  end)
 end)