patch 8.2.4057: Vim9: not fully implementing the autoload mechanism

Problem:    Vim9: not fully implementing the autoload mechanism.
Solution:   Allow for exporting a legacy function.  Improve test coverage.

src/testdir/test_vim9_import.vim

@@ -1,4 +1,5 @@
 " Test import/export of the Vim9 script language.
+" Also the autoload mechanism.
 
 source check.vim
 source term_util.vim
@@ -311,6 +312,28 @@ def Test_vim9_import_export()
   writefile(import_redefining_lines, 'Ximport.vim')
   assert_fails('source Ximport.vim', 'E1213: Redefining imported item "exported"', '', 3)
 
+  var import_missing_dot_lines =<< trim END
+    vim9script
+    import './Xexport.vim' as expo
+    def Test()
+      expo = 9
+    enddef
+    defcompile
+  END
+  writefile(import_missing_dot_lines, 'Ximport.vim')
+  assert_fails('source Ximport.vim', 'E1258:', '', 1)
+
+  var import_missing_name_lines =<< trim END
+    vim9script
+    import './Xexport.vim' as expo
+    def Test()
+      expo.99 = 9
+    enddef
+    defcompile
+  END
+  writefile(import_missing_name_lines, 'Ximport.vim')
+  assert_fails('source Ximport.vim', 'E1259:', '', 3)
+
   var import_assign_wrong_type_lines =<< trim END
     vim9script
     import './Xexport.vim' as expo
@@ -1067,5 +1090,227 @@ def Test_import_gone_when_sourced_twice()
   unlet g:guard
 enddef
 
+" test using an auto-loaded function and variable
+def Test_vim9_autoload()
+  var lines =<< trim END
+     vim9script
+     def some#gettest(): string
+       return 'test'
+     enddef
+     g:some#name = 'name'
+     g:some#dict = {key: 'value'}
+
+     def some#varargs(a1: string, ...l: list<string>): string
+       return a1 .. l[0] .. l[1]
+     enddef
+  END
+
+  mkdir('Xdir/autoload', 'p')
+  writefile(lines, 'Xdir/autoload/some.vim')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  assert_equal('test', g:some#gettest())
+  assert_equal('name', g:some#name)
+  assert_equal('value', g:some#dict.key)
+  g:some#other = 'other'
+  assert_equal('other', g:some#other)
+
+  assert_equal('abc', some#varargs('a', 'b', 'c'))
+
+  # upper case script name works
+  lines =<< trim END
+     vim9script
+     def Other#getOther(): string
+       return 'other'
+     enddef
+  END
+  writefile(lines, 'Xdir/autoload/Other.vim')
+  assert_equal('other', g:Other#getOther())
+
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
+def Test_vim9script_autoload()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  # when using "vim9script autoload" prefix is not needed
+  var lines =<< trim END
+     vim9script autoload
+     g:prefixed_loaded = 'yes'
+
+     export def Gettest(): string
+       return 'test'
+     enddef
+
+     export func GetSome()
+       return 'some'
+     endfunc
+
+     export var name = 'name'
+     export final fname = 'final'
+     export const cname = 'const'
+  END
+  writefile(lines, 'Xdir/autoload/prefixed.vim')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'prefixed.vim'
+      assert_false(exists('g:prefixed_loaded'))
+      assert_equal('test', prefixed.Gettest())
+      assert_equal('yes', g:prefixed_loaded)
+
+      assert_equal('some', prefixed.GetSome())
+      assert_equal('name', prefixed.name)
+      assert_equal('final', prefixed.fname)
+      assert_equal('const', prefixed.cname)
+  END
+  CheckScriptSuccess(lines)
+
+  # can also get the items by autoload name
+  lines =<< trim END
+      call assert_equal('test', prefixed#Gettest())
+      call assert_equal('some', prefixed#GetSome())
+      call assert_equal('name', prefixed#name)
+      call assert_equal('final', prefixed#fname)
+      call assert_equal('const', prefixed#cname)
+  END
+  CheckScriptSuccess(lines)
+
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
+def Test_vim9script_autoload_fails()
+  var lines =<< trim END
+      vim9script autoload
+      var n = 0
+  END
+  CheckScriptFailure(lines, 'E1263:')
+enddef
+
+def Test_import_autoload_fails()
+  var lines =<< trim END
+      vim9script
+      import autoload autoload 'prefixed.vim'
+  END
+  CheckScriptFailure(lines, 'E121: Undefined variable: autoload')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'doesNotExist.vim'
+  END
+  CheckScriptFailure(lines, 'E1264:')
+enddef
+
+" test disassembling an auto-loaded function starting with "debug"
+def Test_vim9_autoload_disass()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  var lines =<< trim END
+     vim9script
+     def debugit#test(): string
+       return 'debug'
+     enddef
+  END
+  writefile(lines, 'Xdir/autoload/debugit.vim')
+
+  lines =<< trim END
+     vim9script
+     def profileit#test(): string
+       return 'profile'
+     enddef
+  END
+  writefile(lines, 'Xdir/autoload/profileit.vim')
+
+  lines =<< trim END
+    vim9script
+    assert_equal('debug', debugit#test())
+    disass debugit#test
+    assert_equal('profile', profileit#test())
+    disass profileit#test
+  END
+  CheckScriptSuccess(lines)
+
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
+" test using a vim9script that is auto-loaded from an autocmd
+def Test_vim9_aucmd_autoload()
+  var lines =<< trim END
+     vim9script
+     def foo#test()
+         echomsg getreg('"')
+     enddef
+  END
+
+  mkdir('Xdir/autoload', 'p')
+  writefile(lines, 'Xdir/autoload/foo.vim')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+  augroup test
+    autocmd TextYankPost * call foo#test()
+  augroup END
+
+  normal Y
+
+  augroup test
+    autocmd!
+  augroup END
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
+" This was causing a crash because suppress_errthrow wasn't reset.
+def Test_vim9_autoload_error()
+  var lines =<< trim END
+      vim9script
+      def crash#func()
+          try
+              for x in List()
+              endfor
+          catch
+          endtry
+          g:ok = true
+      enddef
+      fu List()
+          invalid
+      endfu
+      try
+          alsoinvalid
+      catch /wontmatch/
+      endtry
+  END
+  call mkdir('Xruntime/autoload', 'p')
+  call writefile(lines, 'Xruntime/autoload/crash.vim')
+
+  # run in a separate Vim to avoid the side effects of assert_fails()
+  lines =<< trim END
+    exe 'set rtp^=' .. getcwd() .. '/Xruntime'
+    call crash#func()
+    call writefile(['ok'], 'Xdidit')
+    qall!
+  END
+  writefile(lines, 'Xscript')
+  RunVim([], [], '-S Xscript')
+  assert_equal(['ok'], readfile('Xdidit'))
+
+  delete('Xdidit')
+  delete('Xscript')
+  delete('Xruntime', 'rf')
+
+  lines =<< trim END
+    vim9script
+    var foo#bar = 'asdf'
+  END
+  CheckScriptFailure(lines, 'E461: Illegal variable name: foo#bar', 2)
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/testdir/test_vim9_script.vim

@@ -2994,182 +2994,6 @@ def Test_vim9_copen()
   quit
 enddef
 
-" test using an auto-loaded function and variable
-def Test_vim9_autoload()
-  var lines =<< trim END
-     vim9script
-     def some#gettest(): string
-       return 'test'
-     enddef
-     g:some#name = 'name'
-     g:some#dict = {key: 'value'}
-
-     def some#varargs(a1: string, ...l: list<string>): string
-       return a1 .. l[0] .. l[1]
-     enddef
-  END
-
-  mkdir('Xdir/autoload', 'p')
-  writefile(lines, 'Xdir/autoload/some.vim')
-  var save_rtp = &rtp
-  exe 'set rtp^=' .. getcwd() .. '/Xdir'
-
-  assert_equal('test', g:some#gettest())
-  assert_equal('name', g:some#name)
-  assert_equal('value', g:some#dict.key)
-  g:some#other = 'other'
-  assert_equal('other', g:some#other)
-
-  assert_equal('abc', some#varargs('a', 'b', 'c'))
-
-  # upper case script name works
-  lines =<< trim END
-     vim9script
-     def Other#getOther(): string
-       return 'other'
-     enddef
-  END
-  writefile(lines, 'Xdir/autoload/Other.vim')
-  assert_equal('other', g:Other#getOther())
-
-  # using "vim9script autoload" prefix is not needed
-  lines =<< trim END
-     vim9script autoload
-     g:prefixed_loaded = 'yes'
-     export def Gettest(): string
-       return 'test'
-     enddef
-     export var name = 'name'
-  END
-  writefile(lines, 'Xdir/autoload/prefixed.vim')
-
-  lines =<< trim END
-      vim9script
-      import autoload 'prefixed.vim'
-      assert_false(exists('g:prefixed_loaded'))
-      assert_equal('test', prefixed.Gettest())
-      assert_equal('yes', g:prefixed_loaded)
-      assert_equal('name', prefixed.name)
-  END
-  CheckScriptSuccess(lines)
-
-  # can also get the items by autoload name
-  lines =<< trim END
-      call assert_equal('test', prefixed#Gettest())
-      call assert_equal('name', prefixed#name)
-  END
-  CheckScriptSuccess(lines)
-
-  delete('Xdir', 'rf')
-  &rtp = save_rtp
-enddef
-
-" test disassembling an auto-loaded function starting with "debug"
-def Test_vim9_autoload_disass()
-  mkdir('Xdir/autoload', 'p')
-  var save_rtp = &rtp
-  exe 'set rtp^=' .. getcwd() .. '/Xdir'
-
-  var lines =<< trim END
-     vim9script
-     def debugit#test(): string
-       return 'debug'
-     enddef
-  END
-  writefile(lines, 'Xdir/autoload/debugit.vim')
-
-  lines =<< trim END
-     vim9script
-     def profileit#test(): string
-       return 'profile'
-     enddef
-  END
-  writefile(lines, 'Xdir/autoload/profileit.vim')
-
-  lines =<< trim END
-    vim9script
-    assert_equal('debug', debugit#test())
-    disass debugit#test
-    assert_equal('profile', profileit#test())
-    disass profileit#test
-  END
-  CheckScriptSuccess(lines)
-
-  delete('Xdir', 'rf')
-  &rtp = save_rtp
-enddef
-
-" test using a vim9script that is auto-loaded from an autocmd
-def Test_vim9_aucmd_autoload()
-  var lines =<< trim END
-     vim9script
-     def foo#test()
-         echomsg getreg('"')
-     enddef
-  END
-
-  mkdir('Xdir/autoload', 'p')
-  writefile(lines, 'Xdir/autoload/foo.vim')
-  var save_rtp = &rtp
-  exe 'set rtp^=' .. getcwd() .. '/Xdir'
-  augroup test
-    autocmd TextYankPost * call foo#test()
-  augroup END
-
-  normal Y
-
-  augroup test
-    autocmd!
-  augroup END
-  delete('Xdir', 'rf')
-  &rtp = save_rtp
-enddef
-
-" This was causing a crash because suppress_errthrow wasn't reset.
-def Test_vim9_autoload_error()
-  var lines =<< trim END
-      vim9script
-      def crash#func()
-          try
-              for x in List()
-              endfor
-          catch
-          endtry
-          g:ok = true
-      enddef
-      fu List()
-          invalid
-      endfu
-      try
-          alsoinvalid
-      catch /wontmatch/
-      endtry
-  END
-  call mkdir('Xruntime/autoload', 'p')
-  call writefile(lines, 'Xruntime/autoload/crash.vim')
-
-  # run in a separate Vim to avoid the side effects of assert_fails()
-  lines =<< trim END
-    exe 'set rtp^=' .. getcwd() .. '/Xruntime'
-    call crash#func()
-    call writefile(['ok'], 'Xdidit')
-    qall!
-  END
-  writefile(lines, 'Xscript')
-  RunVim([], [], '-S Xscript')
-  assert_equal(['ok'], readfile('Xdidit'))
-
-  delete('Xdidit')
-  delete('Xscript')
-  delete('Xruntime', 'rf')
-
-  lines =<< trim END
-    vim9script
-    var foo#bar = 'asdf'
-  END
-  CheckScriptFailure(lines, 'E461: Illegal variable name: foo#bar', 2)
-enddef
-
 def Test_script_var_in_autocmd()
   # using a script variable from an autocommand, defined in a :def function in a
   # legacy Vim script, cannot check the variable type.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4057,
 /**/
     4056,
 /**/

src/vim9script.c

@@ -260,11 +260,11 @@ ex_export(exarg_T *eap)
     (void)find_ex_command(eap, NULL, lookup_scriptitem, NULL);
     switch (eap->cmdidx)
     {
-	case CMD_let:
 	case CMD_var:
 	case CMD_final:
 	case CMD_const:
 	case CMD_def:
+	case CMD_function:
 	// case CMD_class:
 	    is_export = TRUE;
 	    do_cmdline(eap->cmd, eap->getline, eap->cookie,