feat(lua): exit 1 on Lua "-l" script error

src/nvim/globals.h

@@ -1042,7 +1042,7 @@ EXTERN int vim_ignored;
 
 // stdio is an RPC channel (--embed).
 EXTERN bool embedded_mode INIT(= false);
-// Do not start a UI nor read/write to stdio (unless embedding).
+// Do not start UI (--headless, -l) nor read/write to stdio (unless embedding).
 EXTERN bool headless_mode INIT(= false);
 
 // uncrustify:on

src/nvim/lua/executor.c

@@ -325,10 +325,11 @@ static int nlua_thr_api_nvim__get_runtime(lua_State *lstate)
 
 /// Copies args starting at `lua_arg0` into the Lua `arg` global.
 ///
-/// Example:
+/// Example (`lua_arg0` points to "--arg1"):
 ///     nvim -l foo.lua --arg1 --arg2
 ///
-/// @note `lua` CLI sets _negative_ `arg` indices to the arguments upto "-e".
+/// @note Lua CLI sets arguments upto "-e" as _negative_ `_G.arg` indices, but we currently don't
+/// follow that convention.
 ///
 /// @see https://www.lua.org/pil/1.4.html
 /// @see https://github.com/premake/premake-core/blob/1c1304637f4f5e50ba8c57aae8d1d80ec3b7aaf2/src/host/premake.c#L563-L594
@@ -1710,10 +1711,10 @@ void ex_luafile(exarg_T *const eap)
   nlua_exec_file((const char *)eap->arg);
 }
 
-/// execute lua code from a file.
+/// Executes Lua code from a file.
 ///
-/// Note: we call the lua global loadfile as opposed to calling luaL_loadfile
+/// Note: we call the Lua global loadfile as opposed to calling luaL_loadfile
-/// in case loadfile has been overridden in the users environment.
+/// in case loadfile was overridden in the user's environment.
 ///
 /// @param  path  path of the file
 ///

src/nvim/main.c

@@ -608,8 +608,9 @@ int main(int argc, char **argv)
   }
 
   if (params.luaf != NULL) {
-    nlua_exec_file(params.luaf);
+    bool lua_ok = nlua_exec_file(params.luaf);
-    // return 0;
+    TIME_MSG("executing Lua -l script");
+    getout(lua_ok ? 0 : 1);
   }
 
   TIME_MSG("before starting main loop");
@@ -659,9 +660,8 @@ void getout(int exitval)
 {
   exiting = true;
 
-  // When running in Ex mode an error causes us to exit with a non-zero exit
+  // On error during Ex mode, exit with a non-zero code.
-  // code.  POSIX requires this, although it's not 100% clear from the
+  // POSIX requires this, although it's not 100% clear from the standard.
-  // standard.
   if (exmode_active) {
     exitval += ex_exitval;
   }
@@ -752,6 +752,7 @@ void getout(int exitval)
   if (did_emsg) {
     // give the user a chance to read the (error) message
     no_wait_return = false;
+    // TODO(justinmk): this may call getout(0), clobbering exitval...
     wait_return(false);
   }
 
@@ -775,10 +776,9 @@ void getout(int exitval)
   os_exit(exitval);
 }
 
-/// Preserve files and exit.
+/// Preserve files, print contents of `IObuff`, and exit 1.
-/// @note IObuff must contain a message.
+///
-/// @note This may be called from deadly_signal() in a signal handler, avoid
+/// May be called from deadly_signal().
-///       unsafe functions, such as allocating memory.
 void preserve_exit(void)
   FUNC_ATTR_NORETURN
 {
@@ -1309,6 +1309,7 @@ static void command_line_scan(mparm_T *parmp)
           break;
 
         case 'l':    // "-l" Lua script: args after "-l".
+          headless_mode = true;
           silent_mode = true;
           p_verbose = 1;
           parmp->no_swap_file = true;
@@ -1403,8 +1404,8 @@ scripterror:
     }
   }
 
-  if (embedded_mode && silent_mode) {
+  if (embedded_mode && (silent_mode || parmp->luaf)) {
-    mainerr(_("--embed conflicts with -es/-Es"), NULL);
+    mainerr(_("--embed conflicts with -es/-Es/-l"), NULL);
   }
 
   // If there is a "+123" or "-c" command, set v:swapcommand to the first one.

test/functional/core/startup_spec.lua

@@ -88,11 +88,11 @@ describe('startup', function()
   end)
 
   describe('-l Lua', function()
-    local function assert_l_out(expected, args_before, args_after)
+    local function assert_l_out(expected, nvim_args, lua_args)
       local args = { nvim_prog, '--clean' }
-      vim.list_extend(args, args_before or {})
+      vim.list_extend(args, nvim_args or {})
       vim.list_extend(args, { '-l', 'test/functional/fixtures/startup.lua' })
-      vim.list_extend(args, args_after or {})
+      vim.list_extend(args, lua_args or {})
       local out = funcs.system(args):gsub('\r\n', '\n')
       return eq(dedent(expected), out)
     end
@@ -115,6 +115,13 @@ describe('startup', function()
       eq(73, eval('v:shell_error'))
     end)
 
+    it('Lua error sets Nvim exitcode', function()
+      eq(0, eval('v:shell_error'))
+      matches('E5113: .* my pearls!!',
+        funcs.system({ nvim_prog, '-l', 'test/functional/fixtures/startup-fail.lua' }))
+      eq(1, eval('v:shell_error'))
+    end)
+
     it('sets _G.arg', function()
       -- nvim -l foo.lua -arg1 -- a b c
       assert_l_out([[
@@ -396,11 +403,13 @@ describe('startup', function()
                     { 'put =mode(1)', 'print', '' }))
   end)
 
-  it('fails on --embed with -es/-Es', function()
+  it('fails on --embed with -es/-Es/-l', function()
-    matches('nvim[.exe]*: %-%-embed conflicts with %-es/%-Es',
+    matches('nvim[.exe]*: %-%-embed conflicts with %-es/%-Es/%-l',
       funcs.system({nvim_prog, '--embed', '-es' }))
-    matches('nvim[.exe]*: %-%-embed conflicts with %-es/%-Es',
+    matches('nvim[.exe]*: %-%-embed conflicts with %-es/%-Es/%-l',
       funcs.system({nvim_prog, '--embed', '-Es' }))
+    matches('nvim[.exe]*: %-%-embed conflicts with %-es/%-Es/%-l',
+      funcs.system({nvim_prog, '--embed', '-l', 'foo.lua' }))
   end)
 
   it('does not crash if --embed is given twice', function()

test/functional/fixtures/startup-fail.lua

@@ -0,0 +1,7 @@
+-- Test "nvim -l foo.lua …" with a Lua error.
+
+local function main()
+  error('my pearls!!')
+end
+
+main()

test/functional/vimscript/system_spec.lua

@@ -1,3 +1,5 @@
+-- Tests for system() and :! shell.
+
 local helpers = require('test.functional.helpers')(after_each)
 
 local assert_alive = helpers.assert_alive