feat(actions): Automatic inline diff preview on hover

README.md

@@ -79,6 +79,7 @@ require('gitsigns').setup {
     ignore_whitespace = false,
   },
   current_line_blame_formatter = '<author>, <author_time:%Y-%m-%d> - <summary>',
+  automatic_hunk_inline = false, -- `:h gitsigns-config-automatic_hunk_inline`
   sign_priority = 6,
   update_debounce = 100,
   status_formatter = nil, -- Use default
@@ -177,6 +178,7 @@ require('gitsigns').setup {
     map('n', '<leader>hu', '<cmd>Gitsigns undo_stage_hunk<CR>')
     map('n', '<leader>hR', '<cmd>Gitsigns reset_buffer<CR>')
     map('n', '<leader>hp', '<cmd>Gitsigns preview_hunk<CR>')
+    map('n', '<leader>hP', '<cmd>Gitsigns automatic_hunk_inline<CR>')
     map('n', '<leader>hb', '<cmd>lua require"gitsigns".blame_line{full=true}<CR>')
     map('n', '<leader>tb', '<cmd>Gitsigns toggle_current_line_blame<CR>')
     map('n', '<leader>hd', '<cmd>Gitsigns diffthis<CR>')
@@ -231,7 +233,7 @@ Ensures signs are always up to date                      | :white_check_mark: *
 Never saves the buffer                                   | :white_check_mark:   | :white_check_mark: :heavy_exclamation_mark: * | * Writes [buffer](https://github.com/airblade/vim-gitgutter/blob/0f98634b92da9a35580b618c11a6d2adc42d9f90/autoload/gitgutter/diff.vim#L106) (and index) to short lived temp files
 Quick jumping between hunks                              | :white_check_mark:   | :white_check_mark:                            |
 Stage/reset/preview individual hunks                     | :white_check_mark:   | :white_check_mark:                            |
-Preview hunks directly in the buffer (inline)            | :white_check_mark: * |                                               | * Via `preview_hunk_inline`
+Preview hunks directly in the buffer (inline)            | :white_check_mark: * |                                               | * Via `preview_hunk_inline` on demand or on hover via `automatic_hunk_inline`
 Stage/reset hunks in range/selection                     | :white_check_mark:   | :white_check_mark: :heavy_exclamation_mark: * | * Only stage
 Stage/reset all hunks in buffer                          | :white_check_mark:   |                                               |
 Undo staged hunks                                        | :white_check_mark:   |                                               |

doc/gitsigns.txt

@@ -32,7 +32,7 @@ For basic setup with all batteries included:
 
 Configuration can be passed to the setup function. Here is an example with most
 of the default settings:
->
+>lua
     require('gitsigns').setup {
       signs = {
         add          = { text = '│' },
@@ -59,6 +59,7 @@ of the default settings:
         ignore_whitespace = false,
       },
       current_line_blame_formatter = '<author>, <author_time:%Y-%m-%d> - <summary>',
+      automatic_hunk_inline = false, -- `:h gitsigns-config-automatic_hunk_inline`
       sign_priority = 6,
       update_debounce = 100,
       status_formatter = nil, -- Use default
@@ -334,6 +335,13 @@ select_hunk()                                         *gitsigns.select_hunk()*
 preview_hunk_inline()                         *gitsigns.preview_hunk_inline()*
                 Preview the hunk at the cursor position inline in the buffer.
 
+automatic_hunk_inline()                     *gitsigns.automatic_hunk_inline()*
+                Preview the hunk at the current cursor position inline in the
+                buffer automatically every time the CursorMoved event is
+                triggered. This function enables or disables the inline diff
+                functionality based on whether the cursor is inside or outside
+                of a hunk.
+
 preview_hunk()                                       *gitsigns.preview_hunk()*
                 Preview the hunk at the cursor position in a floating
                 window. If the preview is already open, calling this
@@ -919,6 +927,14 @@ debug_mode                                        *gitsigns-config-debug_mode*
       Enables debug logging and makes the following functions
       available: `dump_cache`, `debug_messages`, `clear_debug`.
 
+automatic_hunk_inline                  *gitsigns-config-automatic_hunk_inline*
+      Type: `boolean`, Default: `false`
+
+      The `automatic_hunk_inline` function enables automatic inline preview of
+      a hunk's diff when the cursor is inside the hunk. The preview is removed
+      when the cursor moves outside the hunk. This option ensures that any
+      newly attached buffer will have this functionality enabled by default,
+      without the need to manually call `Gitsigns automatic_hunk_inline`.
 
 ==============================================================================
 HIGHLIGHT GROUPS                                   *gitsigns-highlight-groups*

lua/gitsigns/actions.lua

@@ -675,7 +675,13 @@ M.preview_hunk = noautocmd(function()
   popup.create(lines_spec, config.preview_config, 'hunk')
 end)
 
+local preview_hunk_state = { prev_hunk = nil, floating = nil, keep = false }
+
 local function clear_preview_inline(bufnr)
+  preview_hunk_state.prev_hunk = nil
+  if preview_hunk_state.floating then
+    pcall(api.nvim_win_close, preview_hunk_state.floating, true)
+  end
   api.nvim_buf_clear_namespace(bufnr, ns_inline, 0, -1)
 end
 
@@ -686,32 +692,34 @@ M.preview_hunk_inline = function()
   local hunk = get_cursor_hunk(bufnr)
 
   if not hunk then
+    clear_preview_inline(bufnr)
     return
   end
 
+  if hunk == preview_hunk_state.prev_hunk then return end
+
   clear_preview_inline(bufnr)
+  preview_hunk_state.prev_hunk = hunk
 
-  local winid ---@type integer
   manager.show_added(bufnr, ns_inline, hunk)
   if config._inline2 then
     if hunk.removed.count > 0 then
-      winid = manager.show_deleted_in_float(bufnr, ns_inline, hunk)
+      preview_hunk_state.floating = manager.show_deleted_in_float(bufnr, ns_inline, hunk)
     end
   else
     manager.show_deleted(bufnr, ns_inline, hunk)
   end
 
-  api.nvim_create_autocmd({ 'CursorMoved', 'InsertEnter' }, {
-    buffer = bufnr,
-    desc = 'Clear gitsigns inline preview',
-    callback = function()
-      if winid then
-        pcall(api.nvim_win_close, winid, true)
-      end
-      clear_preview_inline(bufnr)
-    end,
-    once = true,
-  })
+  if not preview_hunk_state.keep then
+    api.nvim_create_autocmd({ 'CursorMoved', 'InsertEnter' }, {
+      buffer = bufnr,
+      desc = 'Clear gitsigns inline preview',
+      callback = function()
+        clear_preview_inline(bufnr)
+      end,
+      once = true,
+    })
+  end
 
   -- Virtual lines will be hidden if cursor is on the top row, so automatically
   -- scroll the viewport.
@@ -722,6 +730,33 @@ M.preview_hunk_inline = function()
   end
 end
 
+
+--- Preview the hunk at the current cursor position inline in the buffer automatically
+--- every time the CursorMoved event is triggered. This function enables or disables the inline
+--- diff functionality based on whether the cursor is inside or outside of a hunk.
+M.automatic_hunk_inline = noautocmd(function()
+  local bufnr = current_buf()
+  if not cache[bufnr] then return end
+
+  local group = api.nvim_create_augroup("gitsigns_automatic_hunk_inline", { clear = false })
+
+  -- If the autocmd group already has registered autocmds, clear them and disable the preview
+  if #api.nvim_get_autocmds({ group = group, buffer = bufnr }) > 0 then
+    api.nvim_clear_autocmds({ group = group, buffer = bufnr })
+    clear_preview_inline(bufnr)
+    preview_hunk_state = {}
+  else
+    -- Enable the preview
+    preview_hunk_state.keep = true
+    api.nvim_create_autocmd("CursorMoved", {
+      group = group,
+      buffer = bufnr,
+      callback = M.preview_hunk_inline,
+      desc = "Automatically show inline diff on hover"
+    })
+  end
+end)
+
 --- Select the hunk under the cursor.
 M.select_hunk = function()
   local hunk = get_cursor_hunk()

lua/gitsigns/attach.lua

@@ -356,6 +356,10 @@ local attach_throttled = throttle_by_id(function(cbuf, ctx, aucmd)
   if config.keymaps and not vim.tbl_isempty(config.keymaps) then
     require('gitsigns.mappings')(config.keymaps, cbuf)
   end
+
+  if config.automatic_hunk_inline then
+    require('gitsigns.actions').automatic_hunk_inline()
+  end
 end)
 
 --- Detach Gitsigns from all buffers it is attached to.

lua/gitsigns/config.lua

@@ -77,6 +77,7 @@ end
 --- @field worktrees {toplevel: string, gitdir: string}[]
 --- @field word_diff boolean
 --- @field keymaps table<string,string>
+--- @field automatic_hunk_inline boolean
 --- -- Undocumented
 --- @field _refresh_staged_on_update boolean
 --- @field _blame_cache boolean
@@ -762,6 +763,18 @@ M.schema = {
     ]],
   },
 
+  automatic_hunk_inline = {
+    type = 'boolean',
+    default = false,
+    description = [[
+      The `automatic_hunk_inline` function enables automatic inline preview of
+      a hunk's diff when the cursor is inside the hunk. The preview is removed
+      when the cursor moves outside the hunk. This option ensures that any
+      newly attached buffer will have this functionality enabled by default,
+      without the need to manually call `Gitsigns automatic_hunk_inline`.
+    ]],
+  },
+
   _refresh_staged_on_update = {
     type = 'boolean',
     default = false,