feat: Stage changes by editing index buffers (#260)

sindrets · web-flow · commit c33cfce797b0 · 2022-12-03T14:29:41.000+01:00
diff --git a/README.md b/README.md
@@ -115,6 +115,14 @@ Additional commands for convenience:
 With a Diffview open and the default key bindings, you can cycle through changed
 files with `<tab>` and `<s-tab>` (see configuration to change the key bindings).
 
+#### Staging
+
+You can stage individual hunks by editing any buffer that represents the index
+(after running `:DiffviewOpen` with no `[git-rev]` the entries under "Changes"
+will have the index buffer on the left side, and the entries under "Staged
+changes" will have it on the right side). Once you write to an index buffer the
+index will be updated.
+
 ### `:[range]DiffviewFileHistory [paths] [options]`
 
 Opens a new file history view that lists all commits that affected the given
diff --git a/doc/diffview.txt b/doc/diffview.txt
@@ -55,6 +55,14 @@ COMMANDS                                        *diffview-commands*
             :DiffviewOpen HEAD~2 -- lua/diffview plugin
             :DiffviewOpen d4a7b0d -uno
 <
+
+                                                *diffview-staging*
+        You can stage individual hunks by editing any buffer that represents
+        the index (after running `:DiffviewOpen` with no [git-rev] the entries
+        under "Changes" will have the index buffer on the left side, and the
+        entries under "Staged changes" will have it on the right side). Once
+        you write to an index buffer the index will be updated.
+
                                                 *diffview-merge-tool*
         If you call `:DiffviewOpen` during a merge or a rebase, the view will
         list the conflicted files in their own section. When opening a
@@ -98,7 +106,7 @@ COMMANDS                                        *diffview-commands*
         layouts. To configure a different default layout, see
         |diffview-config-view.x.layout|.
 
-    Options:~
+    Options: ~
         -u[value], --untracked-files[={value}]
                         Specify whether or not to show untracked files. If
                         flag is given without value; defaults to `true`.
@@ -171,7 +179,7 @@ COMMANDS                                        *diffview-commands*
             :'<,'>DiffviewFileHistory
 <
 
-    Options:~
+    Options: ~
         --base={git-rev}
                         Specify a base git rev from which the right side of
                         the diff will be created. Use the special value
@@ -506,7 +514,7 @@ log_options                                     *diffview-config-log_options*
         to define different default log options for history targeting singular
         files, and history targeting multiple paths, and/or directories.
 
-        Fields:~
+        Fields: ~
             {single_file} (`LogOptions`)
                 See |diffview.git.LogOptions|.
 
@@ -535,34 +543,34 @@ hooks                                           *diffview-config-hooks*
         Diffview. The hook events are also available as User autocommands. See
         |diffview-user-autocmds| for more details.
 
-        Available Events:~
+        Available Events: ~
             {view_opened} (`fun(view: View)`)
                 Emitted after a new view has been opened. It's called after
                 initializing the layout in the new tabpage (all windows are
                 ready).
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {view} (`View`)
                         The `View` instance that was opened.
 
             {view_closed} (`fun(view: View)`)
                 Emitted after closing a view.
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {view} (`View`)
                         The `View` instance that was closed.
 
             {view_enter} (`fun(view: View)`)
                 Emitted just after entering the tabpage of a view.
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {view} (`View`)
                         The `View` instance that was entered.
 
             {view_leave} (`fun(view: View)`)
                 Emitted just before leaving the tabpage of a view.
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {view} (`View`)
                         The `View` instance that's about to be left.
 
@@ -577,7 +585,7 @@ hooks                                           *diffview-config-hooks*
                 that |:setlocal| will apply settings to the relevant buffer /
                 window.
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {bufnr} (`integer`)
                         The buffer number of the new buffer.
 
@@ -589,7 +597,7 @@ hooks                                           *diffview-config-hooks*
                 that |:setlocal| will apply settings to the relevant buffer /
                 window.
 
-                Callback Parameters:~
+                Callback Parameters: ~
                     {bufnr} (`integer`)
                         The buffer number of the new buffer.
                     {winid} (`integer`)
@@ -665,7 +673,7 @@ keymaps                                         *diffview-config-keymaps*
 <
 
                                                 *diffview-actions*
-Actions~
+Actions ~
 
         Actions are key-mappable functions. You can access an action through
         the config module: >
@@ -680,7 +688,7 @@ Actions~
         Following are the different contexts described alongside possible
         subjects, upon which actions called from their context, will act on.
 
-        Contexts:~
+        Contexts: ~
             {diff_view}
                 The windows containing the diff buffers in a Diffview.
 
@@ -738,7 +746,7 @@ Actions~
                 Any of the panels.
 
                                                 *diffview-available-actions*
-Available Actions~
+Available Actions ~
 
 close                                           *diffview-actions-close*
         Contexts: `view`, `panel`
@@ -978,7 +986,7 @@ view_windo({cmd}, [targets])                    *diffview-actions-view_windo*
                 |diffview-config-view.x.layout|.
 
                                                 *diffview-unused-actions*
-Unused actions~
+Unused actions ~
 
 Not all actions are mapped by default. The unused actions offer variations on
 the functionality provided by other actions, or just different functionality
@@ -1037,7 +1045,7 @@ file panel.
             • |diffview-actions|
 
                                                 *diffview-file-inference*
-File inference~
+File inference ~
 
 Actions that target a file will infer the target file according to a set of
 simple rules:
@@ -1048,7 +1056,7 @@ simple rules:
           the entry under the cursor.
 
                                                 *diffview-maps-view*
-View maps~
+View maps ~
 
 These maps are available in the diff buffers while a Diffview is the current
 tabpage.
@@ -1087,7 +1095,7 @@ gf                      Open the local version of the file in a new split in a
 y                       Copy the commit hash of the entry under the cursor.
 
                                                 *diffview-maps-file-panel*
-File panel maps~
+File panel maps ~
 
 These maps are available in the file panel buffer.
 
@@ -1134,7 +1142,7 @@ R                       Update the stats and entries in the file list.
 <leader>e               Bring focus to the file panel.
 
                                                 *diffview-maps-file-history-panel*
-File history panel maps~
+File history panel maps ~
 
 These mappings are available in the file history panel buffer (the panel
 listing the commits).
@@ -1174,7 +1182,7 @@ o                       Open the diff for the selected item.
 <leader>e               Bring focus to the file history panel.
 
                                                 *diffview-maps-file-history-option-panel*
-File history option panel maps~
+File history option panel maps ~
 
 These mappings are available from the file history option panel. The option
 panel will allow you to change the flags that will be passed to `git-log`. A
diff --git a/lua/diffview/scene/file_entry.lua b/lua/diffview/scene/file_entry.lua
@@ -9,6 +9,8 @@ local File = lazy.access("diffview.vcs.file", "File") ---@type vcs.File|LazyModu
 local RevType = lazy.access("diffview.vcs.rev", "RevType") ---@type RevType|LazyModule
 local utils = lazy.require("diffview.utils") ---@module "diffview.utils"
 
+local api = vim.api
+
 local M = {}
 
 local fstat_cache = {}
@@ -168,8 +170,28 @@ function FileEntry:validate_stage_buffers(adapter, stat)
   if stat then
     if not cached_stat or cached_stat.mtime < stat.mtime.sec then
       for _, f in ipairs(self.layout:files()) do
-        if f.rev.type == RevType.STAGE then
-          f:dispose_buffer()
+        if f.rev.type == RevType.STAGE and f:is_valid() then
+          if f.rev.stage == 0 then
+            local is_modified = vim.bo[f.bufnr].modified
+
+            if f.blob_hash then
+              local new_hash = f.adapter:file_blob_hash(f.path)
+              if new_hash and new_hash ~= f.blob_hash and is_modified then
+                utils.warn((
+                  "A file was changed in the index since you started editing it!"
+                  .. " Be careful not to lose any staged changes when writing to this buffer: %s"
+                ):format(api.nvim_buf_get_name(f.bufnr)))
+              end
+            elseif not is_modified then
+              -- Should be very rare that we don't have an index-buffer's blob
+              -- hash. But in that case, we can't warn the user when a file
+              -- changes in the index while they're editing its index buffer.
+              f:dispose_buffer()
+            end
+
+          else
+            f:dispose_buffer()
+          end
         end
       end
     end
diff --git a/lua/diffview/utils.lua b/lua/diffview/utils.lua
@@ -387,6 +387,7 @@ end
 
 ---@class utils.system_list.Opt
 ---@field cwd string Working directory of the job.
+---@field writer Job|table|string Something that will write to the stdin of this job.
 ---@field silent boolean Supress log output.
 ---@field fail_on_empty boolean Return code 1 if stdout is empty and code is 0.
 ---@field retry_on_empty integer Number of times to retry job if stdout is empty and code is 0. Implies `fail_on_empty`.
@@ -428,6 +429,7 @@ function M.system_list(cmd, cwd_or_opt)
     command = command,
     args = cmd,
     cwd = opt.cwd,
+    writer = opt.writer,
     on_stderr = function(_, data)
       table.insert(stderr, data)
     end,
@@ -708,6 +710,44 @@ function M.tbl_fmap(t, func)
   return ret
 end
 
+---Set a value in a table, creating all missing intermediate tables in the
+---table path.
+---@param t table
+---@param table_path string|string[] Either a `.` separated string of table keys, or a list.
+---@param value any
+function M.tbl_set(t, table_path, value)
+  local keys = type(table_path) == "table"
+      and table_path
+      or vim.split(table_path, ".", { plain = true })
+
+  local cur = t
+
+  for i = 1, #keys - 1 do
+    local k = keys[i]
+
+    if not cur[k] then
+      cur[k] = {}
+    end
+
+    cur = cur[k]
+  end
+
+  cur[keys[#keys]] = value
+end
+
+---Ensure that the table path is a table in `t`.
+---@param t table
+---@param table_path string|string[] Either a `.` separated string of table keys, or a list.
+function M.tbl_ensure(t, table_path)
+  local keys = type(table_path) == "table"
+      and table_path
+      or vim.split(table_path, ".", { plain = true })
+
+  if not M.tbl_access(t, keys) then
+    M.tbl_set(t, keys, {})
+  end
+end
+
 ---Create a shallow copy of a portion of a vector. Negative numbers indexes
 ---from the end.
 ---@param t vector
diff --git a/lua/diffview/vcs/adapter.lua b/lua/diffview/vcs/adapter.lua
@@ -98,6 +98,14 @@ function VCSAdapter:head_rev()
   oop.abstract_stub()
 end
 
+---Get the hash for a file's blob in a given rev.
+---@param path string
+---@param rev_arg string?
+---@return string?
+function VCSAdapter:file_blob_hash(path, rev_arg)
+  oop.abstract_stub()
+end
+
 ---@return string[] # path to binary for VCS command
 function VCSAdapter:get_command()
   oop.abstract_stub()
@@ -284,6 +292,13 @@ function VCSAdapter:file_restore(path, kind, commit)
   oop.abstract_stub()
 end
 
+---Update the index entry for a given file with the contents of an index buffer.
+---@param file vcs.File
+---@return boolean success
+function VCSAdapter:stage_index_file(file)
+  oop.abstract_stub()
+end
+
 ---@diagnostic enable: unused-local, missing-return
 
 ---@param self VCSAdapter
diff --git a/lua/diffview/vcs/adapters/git/init.lua b/lua/diffview/vcs/adapters/git/init.lua
diff --git a/lua/diffview/vcs/file.lua b/lua/diffview/vcs/file.lua
