vim-patch:9.0.0217: 'shellslash' works differently when sourcing a script again

Problem:    'shellslash' works differently when sourcing a script again.
Solution:   Use the name from the script item. (closes vim/vim#10920)
5a4fff4d94

src/nvim/runtime.c

@@ -1941,9 +1941,6 @@ int do_source(char *fname, int check_other, int is_vimrc)
 
   cookie.level = ex_nesting_level;
 
-  // Keep the sourcing name/lnum, for recursive calls.
-  estack_push(ETYPE_SCRIPT, fname_exp, 0);
-
   // start measuring script load time if --startuptime was passed and
   // time_fd was successfully opened afterwards.
   proftime_T rel_time;
@@ -1966,6 +1963,9 @@ int do_source(char *fname, int check_other, int is_vimrc)
   const sctx_T save_current_sctx = current_sctx;
   si = get_current_script_id(&fname_exp, &current_sctx);
 
+  // Keep the sourcing name/lnum, for recursive calls.
+  estack_push(ETYPE_SCRIPT, (char *)si->sn_name, 0);
+
   if (l_do_profiling == PROF_YES) {
     bool forceit = false;
 

src/nvim/testdir/test_expand_func.vim

@@ -41,7 +41,7 @@ func Test_expand_sfile_and_stack()
   call assert_match('test_expand_func\.vim$', s:sfile)
   let expected = 'script .*testdir/runtest.vim\[\d\+\]\.\.function RunTheTest\[\d\+\]\.\.Test_expand_sfile_and_stack'
   call assert_match(expected .. '$', expand('<sfile>'))
-  call assert_match(expected .. '\[4\]' , expand('<stack>'))
+  call assert_match(expected .. '\[4\]$' , expand('<stack>'))
 
   " Call in script-local function
   call assert_match('script .*testdir/runtest.vim\[\d\+\]\.\.function RunTheTest\[\d\+\]\.\.Test_expand_sfile_and_stack\[7\]\.\.<SNR>\d\+_expand_sfile$', s:expand_sfile())
@@ -59,7 +59,32 @@ func Test_expand_sfile_and_stack()
   call writefile(lines, 'Xstack')
   source Xstack
   call assert_match('\<Xstack\[2\]$', g:stack_value)
+  unlet g:stack_value
   call delete('Xstack')
+
+  if exists('+shellslash')
+    call mkdir('Xshellslash')
+    let lines =<< trim END
+      let g:stack1 = expand('<stack>')
+      set noshellslash
+      let g:stack2 = expand('<stack>')
+      set shellslash
+      let g:stack3 = expand('<stack>')
+    END
+    call writefile(lines, 'Xshellslash/Xstack')
+    " Test that changing 'shellslash' always affects the result of expand()
+    " when sourcing a script multiple times.
+    for i in range(2)
+      source Xshellslash/Xstack
+      call assert_match('\<Xshellslash/Xstack\[1\]$', g:stack1)
+      call assert_match('\<Xshellslash\\Xstack\[3\]$', g:stack2)
+      call assert_match('\<Xshellslash/Xstack\[5\]$', g:stack3)
+      unlet g:stack1
+      unlet g:stack2
+      unlet g:stack3
+    endfor
+    call delete('Xshellslash', 'rf')
+  endif
 endfunc
 
 func Test_expand_slnum()