feat(git): Get all file history data with a single job

Further improves the stability of the history updating process.

- Implement empty log entries (some commits may be identical to their
  parent. And some merge commits may not list any changes depending on
  the value of `--diff-merges`, but they should still be included in the
  history).
- Changed default options for single file history:
  - `--follow` is now set by default.
  - `--diff-merges` is set to `first-parent` by default.

Author: sindrets

lua/diffview/config.lua

@@ -83,7 +83,8 @@ M.defaults = {
       ---@type ConfigLogOptions
       git = {
         single_file = {
-          diff_merges = "combined",
+          diff_merges = "first-parent",
+          follow = true,
         },
         multi_file = {
           diff_merges = "first-parent",

lua/diffview/scene/file_entry.lua

@@ -1,6 +1,7 @@
 local lazy = require("diffview.lazy")
 local oop = require("diffview.oop")
 
+local Diff1 = lazy.access("diffview.scene.layouts.diff_1", "Diff1") ---@type Diff1|LazyModule
 local Diff2 = lazy.access("diffview.scene.layouts.diff_2", "Diff2") ---@type Diff2|LazyModule
 local File = lazy.access("diffview.vcs.file", "File") ---@type vcs.File|LazyModule
 local RevType = lazy.access("diffview.vcs.rev", "RevType") ---@type RevType|LazyModule
@@ -279,6 +280,11 @@ function FileEntry:has_patch_folds()
   return true
 end
 
+---@return boolean
+function FileEntry:is_null_entry()
+  return self.path == "null" and self.layout:get_main_win().file == File.NULL_FILE
+end
+
 ---@static
 ---@param adapter VCSAdapter
 function FileEntry.update_index_stat(adapter, stat)
@@ -336,5 +342,19 @@ function FileEntry.with_layout(layout_class, opt)
   })
 end
 
+function FileEntry.new_null_entry(adapter)
+  return FileEntry({
+    adapter = adapter,
+    path = "null",
+    kind = "working",
+    binary = false,
+    nulled = true,
+    layout = Diff1({
+      b = File.NULL_FILE,
+    })
+  })
+end
+
 M.FileEntry = FileEntry
+
 return M

lua/diffview/scene/views/file_history/render.lua

@@ -3,6 +3,7 @@ local config = require("diffview.config")
 local hl = require("diffview.hl")
 local utils = require("diffview.utils")
 
+local fmt = string.format
 local logger = DiffviewGlobal.logger
 local perf = PerfTimer("[FileHistoryPanel] Render internal")
 local pl = utils.path
@@ -15,23 +16,32 @@ local function render_files(comp, files)
   for i, file in ipairs(files) do
     comp:add_text(i == #files and "└   " or "│   ", "DiffviewNonText")
 
-    if file.status then
-      comp:add_text(file.status .. " ", hl.get_git_hl(file.status))
-    end
+    if file:is_null_entry() then
+      comp:add_text(
+        "No diff",
+        file.active and "DiffviewFilePanelSelected" or "DiffviewFilePanelFileName"
+      )
+    else
+      if file.status then
+        comp:add_text(file.status .. " ", hl.get_git_hl(file.status))
+      else
+        comp:add_text("-" .. " ", "DiffviewNonText")
+      end
 
-    local icon, icon_hl = hl.get_file_icon(file.basename, file.extension)
-    comp:add_text(icon, icon_hl)
+      local icon, icon_hl = hl.get_file_icon(file.basename, file.extension)
+      comp:add_text(icon, icon_hl)
 
-    if #file.parent_path > 0 then
-      comp:add_text(file.parent_path .. "/", "DiffviewFilePanelPath")
-    end
+      if #file.parent_path > 0 then
+        comp:add_text(file.parent_path .. "/", "DiffviewFilePanelPath")
+      end
 
-    comp:add_text(file.basename, file.active and "DiffviewFilePanelSelected" or "DiffviewFilePanelFileName")
+      comp:add_text(file.basename, file.active and "DiffviewFilePanelSelected" or "DiffviewFilePanelFileName")
 
-    if file.stats then
-      comp:add_text(" " .. file.stats.additions, "DiffviewFilePanelInsertions")
-      comp:add_text(", ")
-      comp:add_text(tostring(file.stats.deletions), "DiffviewFilePanelDeletions")
+      if file.stats then
+        comp:add_text(" " .. file.stats.additions, "DiffviewFilePanelInsertions")
+        comp:add_text(", ")
+        comp:add_text(tostring(file.stats.deletions), "DiffviewFilePanelDeletions")
+      end
     end
 
     comp:ln()
@@ -47,7 +57,7 @@ end
 local function render_entries(panel, parent, entries, updating)
   local c = config.get_config()
   local max_num_files = -1
-  local max_len_stats = 7
+  local max_len_stats = -1
 
   for _, entry in ipairs(entries) do
     if #entry.files > max_num_files then
@@ -72,39 +82,60 @@ local function render_entries(panel, parent, entries, updating)
     end
 
     local entry_struct = parent[i]
-    local comp = entry_struct.commit.comp
+    local comp = entry_struct.commit.comp --[[@as RenderComponent ]]
 
     if not entry.single_file then
       comp:add_text((entry.folded and c.signs.fold_closed or c.signs.fold_open) .. " ", "CursorLineNr")
     end
 
     if entry.status then
       comp:add_text(entry.status, hl.get_git_hl(entry.status))
+    else
+      comp:add_text("-", "DiffviewNonText")
     end
 
     if not entry.single_file then
-      local counter = " "
-        .. utils.str_left_pad(tostring(#entry.files), #tostring(max_num_files))
-        .. (" file%s"):format(#entry.files > 1 and "s" or " ")
-      comp:add_text(counter, "DiffviewFilePanelCounter")
+      local s_num_files = tostring(max_num_files)
+
+      if entry.nulled then
+        comp:add_text(utils.str_center_pad("empty", #s_num_files + 7), "DiffviewFilePanelCounter")
+      else
+        comp:add_text(
+          fmt(
+            " %s file%s",
+            utils.str_left_pad(tostring(#entry.files), #s_num_files),
+            #entry.files > 1 and "s" or " "
+          ),
+          "DiffviewFilePanelCounter"
+        )
+      end
     end
 
-    if entry.stats then
-      local adds = tostring(entry.stats.additions)
-      local dels = tostring(entry.stats.deletions)
-      comp:add_text(" | ", "DiffviewNonText")
-      comp:add_text(adds, "DiffviewFilePanelInsertions")
-      comp:add_text(string.rep(" ", max_len_stats - (#adds + #dels)))
-      comp:add_text(dels, "DiffviewFilePanelDeletions")
+    if max_len_stats ~= -1 then
+      local adds = { "-", "DiffviewNonText" }
+      local dels = { "-", "DiffviewNonText" }
+
+      if entry.stats and entry.stats.additions then
+        adds = { tostring(entry.stats.additions), "DiffviewFilePanelInsertions" }
+      end
+
+      if entry.stats and entry.stats.deletions then
+        dels = { tostring(entry.stats.deletions), "DiffviewFilePanelDeletions" }
+      end
+
       comp:add_text(" | ", "DiffviewNonText")
+      comp:add_text(unpack(adds))
+      comp:add_text(string.rep(" ", max_len_stats - (#adds[1] + #dels[1])))
+      comp:add_text(unpack(dels))
+      comp:add_text(" |", "DiffviewNonText")
     end
 
     if entry.commit.hash then
-      comp:add_text(entry.commit.hash:sub(1, 8) .. " ", "DiffviewSecondary")
+      comp:add_text(" " .. entry.commit.hash:sub(1, 8), "DiffviewSecondary")
     end
 
     if entry.commit.ref_names then
-      comp:add_text(("(%s) "):format(entry.commit.ref_names), "DiffviewReference")
+      comp:add_text((" (%s)"):format(entry.commit.ref_names), "DiffviewReference")
     end
 
     local subject = utils.str_trunc(entry.commit.subject, 72)
@@ -114,18 +145,18 @@ local function render_entries(panel, parent, entries, updating)
     end
 
     comp:add_text(
-      subject .. " ",
+      " " .. subject,
       panel.cur_item[1] == entry and "DiffviewFilePanelSelected" or "DiffviewFilePanelFileName"
     )
 
     if entry.commit then
       -- 3 months
       local date = (
-          os.difftime(os.time(), entry.commit.time) > 60 * 60 * 24 * 30 * 3
-            and entry.commit.iso_date
+        os.difftime(os.time(), entry.commit.time) > 60 * 60 * 24 * 30 * 3
+          and entry.commit.iso_date
           or entry.commit.rel_date
-        )
-      comp:add_text(entry.commit.author .. ", " .. date, "DiffviewFilePanelPath")
+      )
+      comp:add_text(" " .. entry.commit.author .. ", " .. date, "DiffviewFilePanelPath")
     end
 
     comp:ln()

lua/diffview/utils.lua

@@ -31,23 +31,14 @@ end
 ---@param schedule? boolean Schedule the echo call.
 function M.echo_multiln(msg, hl, schedule)
   if schedule then
-    vim.schedule(function()
-      M.echo_multiln(msg, hl, false)
-    end)
+    vim.schedule(function() M.echo_multiln(msg, hl, false) end)
     return
   end
 
-  vim.cmd("echohl " .. (hl or "None"))
-  if type(msg) ~= "table" then
-    msg = { msg }
-  end
-  for _, chunk in ipairs(msg) do
-    for _, line in ipairs(vim.split(chunk, "\n", { trimempty = false })) do
-      line = line:gsub('["|\t]', { ['"'] = [[\"]], ["\t"] = "        " })
-      vim.cmd(string.format('echom "%s"', line))
-    end
-  end
-  vim.cmd("echohl None")
+  if type(msg) ~= "table" then msg = { msg } end
+
+  local text = table.concat(msg, "\n")
+  api.nvim_echo({ { text, hl } }, true, {})
 end
 
 ---@param msg string|string[]
@@ -61,7 +52,7 @@ function M.info(msg, schedule)
   end
   msg = M.vec_slice(msg)
   msg[1] = "[Diffview.nvim] " .. msg[1]
-  M.echo_multiln(msg, "Directory", schedule)
+  M.echo_multiln(msg, "DiagnosticInfo", schedule)
 end
 
 ---@param msg string|string[]
@@ -1252,9 +1243,10 @@ function M.temp_win(bufnr, enter)
 end
 
 ---Create a copy of `func` bound to the given arguments.
----@param func function
+---@generic T
+---@param func fun(...): T
 ---@param ... any Arguments to prepend to arguments provided to the bound function when invoking `func`.
----@return fun(...): unknown
+---@return fun(...): T
 function M.bind(func, ...)
   local bound_args = M.tbl_pack(...)