vim-patch:9.1.1964: Wrong display when using setline() at hit-enter prompt (#36878)

Problem:  Wrong display when using setline() at hit-enter prompt
          (after 8.2.3204).
Solution: Only skip scrolling for changed lines in top area if it's
          scrolled down due to w_topline change. Also add more testing
          for what 8.2.3204 fixed (zeertzjq).

closes: vim/vim#18887

https://github.com/vim/vim/commit/e72eacceab2647e37e7d7a8a70e89dcd6ad01288

src/nvim/drawscreen.c

@@ -2039,11 +2039,11 @@ static void win_update(win_T *wp)
       // When at start of changed lines: May scroll following lines
       // up or down to minimize redrawing.
       // Don't do this when the change continues until the end.
-      // Don't scroll the top area which was already scrolled above,
+      // Don't scroll for changed lines in the top area if that's already
-      // but do scroll for changed lines below the top area.
+      // done above, but do scroll for changed lines below the top area.
       if (!scrolled_for_mod && mod_bot != MAXLNUM
           && lnum >= mod_top && lnum < MAX(mod_bot, mod_top + 1)
-          && row >= top_end) {
+          && (!scrolled_down || row >= top_end)) {
         scrolled_for_mod = true;
 
         int old_cline_height = 0;

test/functional/legacy/display_spec.lua

@@ -48,13 +48,19 @@ describe('display', function()
       setlocal scrolloff=5 signcolumn=yes
       call setline(1, range(1, 100))
       call sign_define('foo', #{text: '>'})
-      call sign_place(1, 'bar', 'foo', bufnr(), #{lnum: 73})
+      call sign_place(1, 'bar', 'foo', bufnr(), #{lnum: 71})
-      call sign_place(2, 'bar', 'foo', bufnr(), #{lnum: 74})
+      call sign_place(2, 'bar', 'foo', bufnr(), #{lnum: 72})
-      call sign_place(3, 'bar', 'foo', bufnr(), #{lnum: 75})
+      call sign_place(3, 'bar', 'foo', bufnr(), #{lnum: 73})
+      call sign_place(4, 'bar', 'foo', bufnr(), #{lnum: 74})
+      call sign_place(5, 'bar', 'foo', bufnr(), #{lnum: 75})
       normal! G
       autocmd CursorMoved * if line('.') == 79
-                        \ |   call sign_unplace('bar', #{id: 2})
+                        \ |   call sign_unplace('bar', #{id: 4})
                         \ |   call setline(80, repeat('foo', 15))
+                        \ | elseif line('.') == 78
+                        \ |   call setline(72, repeat('bar', 10))
+                        \ | elseif line('.') == 77
+                        \ |   call sign_unplace('bar', #{id: 2})
                         \ | endif
     ]])
     screen:expect([[
@@ -144,6 +150,63 @@ describe('display', function()
       {7:  }84                |
                           |
     ]])
+    feed('k')
+    screen:expect([[
+      {7:  }barbarbarbarbarbar|
+      {7:  }barbarbarbar      |
+      {7:> }73                |
+      {7:  }74                |
+      {7:> }75                |
+      {7:  }76                |
+      {7:  }^77                |
+      {7:  }78                |
+      {7:  }79                |
+      {7:  }foofoofoofoofoofoo|*2
+      {7:  }foofoofoo         |
+      {7:  }81                |
+      {7:  }82                |
+                          |
+    ]])
+  end)
+
+  -- oldtest: Test_display_hit_enter_setline()
+  it('using setline() at hit-enter prompt', function()
+    local screen = Screen.new(40, 8)
+    exec([[
+      call setline(1, range(1, 100))
+    ]])
+    screen:expect([[
+      ^1                                       |
+      2                                       |
+      3                                       |
+      4                                       |
+      5                                       |
+      6                                       |
+      7                                       |
+                                              |
+    ]])
+    feed([[:echo "abc\ndef\nghi"<CR>]])
+    screen:expect([[
+      1                                       |
+      2                                       |
+      3                                       |
+      {3:                                        }|
+      abc                                     |
+      def                                     |
+      ghi                                     |
+      {6:Press ENTER or type command to continue}^ |
+    ]])
+    feed([[:call setline(2, repeat('foo', 35))<CR>]])
+    screen:expect([[
+      ^1                                       |
+      foofoofoofoofoofoofoofoofoofoofoofoofoof|
+      oofoofoofoofoofoofoofoofoofoofoofoofoofo|
+      ofoofoofoofoofoofoofoofoo               |
+      3                                       |
+      4                                       |
+      5                                       |
+                                              |
+    ]])
   end)
 
   local function run_test_display_lastline(euro)

test/old/testdir/test_display.vim

@@ -275,13 +275,19 @@ func Test_display_scroll_setline()
     setlocal scrolloff=5 signcolumn=yes
     call setline(1, range(1, 100))
     call sign_define('foo', #{text: '>'})
-    call sign_place(1, 'bar', 'foo', bufnr(), #{lnum: 73})
+    call sign_place(1, 'bar', 'foo', bufnr(), #{lnum: 71})
-    call sign_place(2, 'bar', 'foo', bufnr(), #{lnum: 74})
+    call sign_place(2, 'bar', 'foo', bufnr(), #{lnum: 72})
-    call sign_place(3, 'bar', 'foo', bufnr(), #{lnum: 75})
+    call sign_place(3, 'bar', 'foo', bufnr(), #{lnum: 73})
+    call sign_place(4, 'bar', 'foo', bufnr(), #{lnum: 74})
+    call sign_place(5, 'bar', 'foo', bufnr(), #{lnum: 75})
     normal! G
     autocmd CursorMoved * if line('.') == 79
-                      \ |   call sign_unplace('bar', #{id: 2})
+                      \ |   call sign_unplace('bar', #{id: 4})
                       \ |   call setline(80, repeat('foo', 15))
+                      \ | elseif line('.') == 78
+                      \ |   call setline(72, repeat('bar', 10))
+                      \ | elseif line('.') == 77
+                      \ |   call sign_unplace('bar', #{id: 2})
                       \ | endif
   END
   call writefile(lines, 'XscrollSetline.vim', 'D')
@@ -296,6 +302,27 @@ func Test_display_scroll_setline()
   call VerifyScreenDump(buf, 'Test_display_scroll_setline_4', {})
   call term_sendkeys(buf, 'k')
   call VerifyScreenDump(buf, 'Test_display_scroll_setline_5', {})
+  call term_sendkeys(buf, 'k')
+  call VerifyScreenDump(buf, 'Test_display_scroll_setline_6', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
+func Test_display_hit_enter_setline()
+  CheckScreendump
+
+  let lines =<< trim END
+    call setline(1, range(1, 100))
+  END
+  call writefile(lines, 'XhitEnterSetline.vim', 'D')
+
+  let buf = RunVimInTerminal('-S XhitEnterSetline.vim', #{rows: 8, cols: 40})
+  call VerifyScreenDump(buf, 'Test_display_hit_enter_setline_1', {})
+  call term_sendkeys(buf, ':echo "abc\ndef\nghi"')
+  call term_sendkeys(buf, "\<CR>")
+  call VerifyScreenDump(buf, 'Test_display_hit_enter_setline_2', {})
+  call term_sendkeys(buf, ":call setline(2, repeat('foo', 35))\<CR>")
+  call VerifyScreenDump(buf, 'Test_display_hit_enter_setline_3', {})
 
   call StopVimInTerminal(buf)
 endfunc