feat(api): add nvim__redraw for more granular redrawing

Experimental and subject to future changes.
Add a way to redraw certain elements that are not redrawn while Nvim is waiting
for input, or currently have no API to do so. This API covers all that can be
done with the :redraw* commands, in addition to the following new features:
- Immediately move the cursor to a (non-current) window.
- Target a specific window or buffer to mark for redraw.
- Mark a buffer range for redraw (replaces nvim__buf_redraw_range()).
- Redraw the 'statuscolumn'.

1 files changed, 212 insertions, 0 deletions

diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 2d3871a37d..fbb6d42633 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -5016,4 +5016,216 @@ describe('API', function()
       eq(false, exec_lua('return _G.success'))
     end)
   end)
+
+  it('nvim__redraw', function()
+    local screen = Screen.new(60, 5)
+    screen:attach()
+    local win = api.nvim_get_current_win()
+    eq('at least one action required', pcall_err(api.nvim__redraw, {}))
+    eq('at least one action required', pcall_err(api.nvim__redraw, { buf = 0 }))
+    eq('at least one action required', pcall_err(api.nvim__redraw, { win = 0 }))
+    eq("cannot use both 'buf' and 'win'", pcall_err(api.nvim__redraw, { buf = 0, win = 0 }))
+    feed(':echo getchar()<CR>')
+    fn.setline(1, 'foobar')
+    command('vnew')
+    fn.setline(1, 'foobaz')
+    -- Can flush pending screen updates
+    api.nvim__redraw({ flush = true })
+    screen:expect({
+      grid = [[
+        foobaz                        │foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:[No Name] [+]                  }{2:[No Name] [+]                }|
+        ^:echo getchar()                                             |
+      ]],
+    })
+    -- Can update the grid cursor position #20793
+    api.nvim__redraw({ cursor = true })
+    screen:expect({
+      grid = [[
+        ^foobaz                        │foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:[No Name] [+]                  }{2:[No Name] [+]                }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Also in non-current window
+    api.nvim__redraw({ cursor = true, win = win })
+    screen:expect({
+      grid = [[
+        foobaz                        │^foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:[No Name] [+]                  }{2:[No Name] [+]                }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update the 'statusline' in a single window
+    api.nvim_set_option_value('statusline', 'statusline1', { win = 0 })
+    api.nvim_set_option_value('statusline', 'statusline2', { win = win })
+    api.nvim__redraw({ cursor = true, win = 0, statusline = true })
+    screen:expect({
+      grid = [[
+        ^foobaz                        │foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:statusline1                    }{2:[No Name] [+]                }|
+        :echo getchar()                                             |
+      ]],
+    })
+    api.nvim__redraw({ win = win, statusline = true })
+    screen:expect({
+      grid = [[
+        ^foobaz                        │foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:statusline1                    }{2:statusline2                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update the 'statusline' in all windows
+    api.nvim_set_option_value('statusline', '', { win = win })
+    api.nvim_set_option_value('statusline', 'statusline3', {})
+    api.nvim__redraw({ statusline = true })
+    screen:expect({
+      grid = [[
+        ^foobaz                        │foobar                       |
+        {1:~                             }│{1:~                            }|*2
+        {3:statusline3                    }{2:statusline3                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update the 'statuscolumn'
+    api.nvim_set_option_value('statuscolumn', 'statuscolumn', { win = win })
+    api.nvim__redraw({ statuscolumn = true })
+    screen:expect({
+      grid = [[
+        ^foobaz                        │{8:statuscolumn}foobar           |
+        {1:~                             }│{1:~                            }|*2
+        {3:statusline3                    }{2:statusline3                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update the 'winbar'
+    api.nvim_set_option_value('winbar', 'winbar', { win = 0 })
+    api.nvim__redraw({ win = 0, winbar = true })
+    screen:expect({
+      grid = [[
+        {5:^winbar                        }│{8:statuscolumn}foobar           |
+        foobaz                        │{1:~                            }|
+        {1:~                             }│{1:~                            }|
+        {3:statusline3                    }{2:statusline3                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update the 'tabline'
+    api.nvim_set_option_value('showtabline', 2, {})
+    api.nvim_set_option_value('tabline', 'tabline', {})
+    api.nvim__redraw({ tabline = true })
+    screen:expect({
+      grid = [[
+        {2:^tabline                                                     }|
+        {5:winbar                        }│{8:statuscolumn}foobar           |
+        foobaz                        │{1:~                            }|
+        {3:statusline3                    }{2:statusline3                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update multiple status widgets
+    api.nvim_set_option_value('tabline', 'tabline2', {})
+    api.nvim_set_option_value('statusline', 'statusline4', {})
+    api.nvim__redraw({ statusline = true, tabline = true })
+    screen:expect({
+      grid = [[
+        {2:^tabline2                                                    }|
+        {5:winbar                        }│{8:statuscolumn}foobar           |
+        foobaz                        │{1:~                            }|
+        {3:statusline4                    }{2:statusline4                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update all status widgets
+    api.nvim_set_option_value('tabline', 'tabline3', {})
+    api.nvim_set_option_value('statusline', 'statusline5', {})
+    api.nvim_set_option_value('statuscolumn', 'statuscolumn2', {})
+    api.nvim_set_option_value('winbar', 'winbar2', {})
+    api.nvim__redraw({ statuscolumn = true, statusline = true, tabline = true, winbar = true })
+    screen:expect({
+      grid = [[
+        {2:^tabline3                                                    }|
+        {5:winbar2                       }│{5:winbar2                      }|
+        {8:statuscolumn2}foobaz           │{8:statuscolumn}foobar           |
+        {3:statusline5                    }{2:statusline5                  }|
+        :echo getchar()                                             |
+      ]],
+    })
+    -- Can update status widget for a specific window
+    feed('<CR><CR>')
+    command('let g:status=0')
+    api.nvim_set_option_value('statusline', '%{%g:status%}', { win = 0 })
+    command('vsplit')
+    screen:expect({
+      grid = [[
+        {2:tabline3                                                    }|
+        {5:winbar2             }│{5:winbar2            }│{5:winbar2            }|
+        {8:statuscolumn2}^foobaz │{8:statuscolumn2}foobaz│{8:statuscolumn}foobar |
+        {3:0                    }{2:0                   statusline5        }|
+        13                                                          |
+      ]],
+    })
+    command('let g:status=1')
+    api.nvim__redraw({ win = 0, statusline = true })
+    screen:expect({
+      grid = [[
+        {2:tabline3                                                    }|
+        {5:winbar2             }│{5:winbar2            }│{5:winbar2            }|
+        {8:statuscolumn2}^foobaz │{8:statuscolumn2}foobaz│{8:statuscolumn}foobar |
+        {3:1                    }{2:0                   statusline5        }|
+        13                                                          |
+      ]],
+    })
+    -- Can update status widget for a specific buffer
+    command('let g:status=2')
+    api.nvim__redraw({ buf = 0, statusline = true })
+    screen:expect({
+      grid = [[
+        {2:tabline3                                                    }|
+        {5:winbar2             }│{5:winbar2            }│{5:winbar2            }|
+        {8:statuscolumn2}^foobaz │{8:statuscolumn2}foobaz│{8:statuscolumn}foobar |
+        {3:2                    }{2:2                   statusline5        }|
+        13                                                          |
+      ]],
+    })
+    -- valid = true does not draw any lines on its own
+    exec_lua([[
+      lines = 0
+      ns = vim.api.nvim_create_namespace('')
+      on_win = function()
+        if do_win then
+          vim.api.nvim_buf_set_extmark(0, ns, 0, 0, { hl_group = 'IncSearch', end_col = 6 })
+        end
+      end
+      vim.api.nvim_set_decoration_provider(ns, {
+        on_win = on_win,
+        on_line = function()
+          lines = lines + 1
+        end,
+      })
+    ]])
+    local lines = exec_lua('return lines')
+    api.nvim__redraw({ buf = 0, valid = true, flush = true })
+    eq(lines, exec_lua('return lines'))
+    -- valid = false does
+    api.nvim__redraw({ buf = 0, valid = false, flush = true })
+    neq(lines, exec_lua('return lines'))
+    -- valid = true does redraw lines if affected by on_win callback
+    exec_lua('do_win = true')
+    api.nvim__redraw({ buf = 0, valid = true, flush = true })
+    screen:expect({
+      grid = [[
+        {2:tabline3                                                    }|
+        {5:winbar2             }│{5:winbar2            }│{5:winbar2            }|
+        {8:statuscolumn2}{2:^foobaz} │{8:statuscolumn2}{2:foobaz}│{8:statuscolumn}foobar |
+        {3:2                    }{2:2                   statusline5        }|
+        13                                                          |
+      ]],
+    })
+  end)
 end)