test: move exec_lua logic to separate module

By making it a separate module, the embedded Nvim session can require
this module directly instead of setup code sending over the module via
RPC.

Also make exec_lua wrap _G.print so messages can be seen
in the test output immediately as the exec_lua returns.

1 files changed, 148 insertions, 0 deletions

diff --git a/test/functional/testnvim/exec_lua.lua b/test/functional/testnvim/exec_lua.lua
new file mode 100644
index 0000000000..ddd9905ce7
--- /dev/null
+++ b/test/functional/testnvim/exec_lua.lua
@@ -0,0 +1,148 @@
+--- @param f function
+--- @return table<string,any>
+local function get_upvalues(f)
+  local i = 1
+  local upvalues = {} --- @type table<string,any>
+  while true do
+    local n, v = debug.getupvalue(f, i)
+    if not n then
+      break
+    end
+    upvalues[n] = v
+    i = i + 1
+  end
+  return upvalues
+end
+
+--- @param f function
+--- @param upvalues table<string,any>
+local function set_upvalues(f, upvalues)
+  local i = 1
+  while true do
+    local n = debug.getupvalue(f, i)
+    if not n then
+      break
+    end
+    if upvalues[n] then
+      debug.setupvalue(f, i, upvalues[n])
+    end
+    i = i + 1
+  end
+end
+
+--- @param messages string[]
+--- @param ... ...
+local function add_print(messages, ...)
+  local msg = {} --- @type string[]
+  for i = 1, select('#', ...) do
+    msg[#msg + 1] = tostring(select(i, ...))
+  end
+  table.insert(messages, table.concat(msg, '\t'))
+end
+
+local invalid_types = {
+  ['thread'] = true,
+  ['function'] = true,
+  ['userdata'] = true,
+}
+
+--- @param r any[]
+local function check_returns(r)
+  for k, v in pairs(r) do
+    if invalid_types[type(v)] then
+      error(
+        string.format(
+          "Return index %d with value '%s' of type '%s' cannot be serialized over RPC",
+          k,
+          tostring(v),
+          type(v)
+        ),
+        2
+      )
+    end
+  end
+end
+
+local M = {}
+
+--- This is run in the context of the remote Nvim instance.
+--- @param bytecode string
+--- @param upvalues table<string,any>
+--- @param ... any[]
+--- @return any[] result
+--- @return table<string,any> upvalues
+--- @return string[] messages
+function M.handler(bytecode, upvalues, ...)
+  local messages = {} --- @type string[]
+  local orig_print = _G.print
+
+  function _G.print(...)
+    add_print(messages, ...)
+    return orig_print(...)
+  end
+
+  local f = assert(loadstring(bytecode))
+
+  set_upvalues(f, upvalues)
+
+  -- Run in pcall so we can return any print messages
+  local ret = { pcall(f, ...) } --- @type any[]
+
+  _G.print = orig_print
+
+  local new_upvalues = get_upvalues(f)
+
+  -- Check return value types for better error messages
+  check_returns(ret)
+
+  return ret, new_upvalues, messages
+end
+
+--- @param session test.Session
+--- @param lvl integer
+--- @param code function
+--- @param ... ...
+local function run(session, lvl, code, ...)
+  local stat, rv = session:request(
+    'nvim_exec_lua',
+    [[return { require('test.functional.testnvim.exec_lua').handler(...) }]],
+    { string.dump(code), get_upvalues(code), ... }
+  )
+
+  if not stat then
+    error(rv[2], 2)
+  end
+
+  --- @type any[], table<string,any>, string[]
+  local ret, upvalues, messages = unpack(rv)
+
+  for _, m in ipairs(messages) do
+    print(m)
+  end
+
+  if not ret[1] then
+    error(ret[2], 2)
+  end
+
+  -- Update upvalues
+  if next(upvalues) then
+    local caller = debug.getinfo(lvl)
+    local i = 0
+
+    -- On PUC-Lua, if the function is a tail call, then func will be nil.
+    -- In this case we need to use the caller.
+    while not caller.func do
+      i = i + 1
+      caller = debug.getinfo(lvl + i)
+    end
+    set_upvalues(caller.func, upvalues)
+  end
+
+  return unpack(ret, 2, table.maxn(ret))
+end
+
+return setmetatable(M, {
+  __call = function(_, ...)
+    return run(...)
+  end,
+})