refactor(diff): rename diff_opts.layout "inline" to "unified" (#295)

## Summary

Renames the `diff_opts.layout = "inline"` option (added in #195, queued
for v0.4.0 via release-please #279) to **`"unified"`**, before it ships
in a tagged release. Tracked in #293.

[@wookayin pointed
out](#195 (comment))
that the shipped `"inline"` mode isn't a true "inline" diff in the VS
Code sense — it renders a unified diff in a separate `rightbelow vsplit`
pane, not an in-place virtual-text overlay in the same window. Naming it
`"inline"` now would force a breaking rename later, once we add the real
in-place overlay (the mode that most deserves the name `"inline"`).
Renaming is free now (not yet released) and a breaking change after #279
merges.

## What changed

- **Config value** `"inline"` → `"unified"`: validation + error message
(`config.lua`), the `ClaudeCodeDiffLayout` type alias (`types.lua`), all
four dispatch sites (`diff.lua`), and the stored `layout` value
(`diff_inline.lua`).
- **User-facing buffer name**: `<file> (inline diff)` → `<file> (unified
diff)`.
- **Docs**: README layout enum + label; a `CHANGELOG.md` `[Unreleased]`
entry for `layout = "unified"`.
- **Tests**: the accept test now expects `"unified"`; a new test asserts
the former `"inline"` is rejected.

## Decisions

- **No deprecated alias.** `"inline"` was never in a tagged release, so
there's no backward-compat obligation, and rejecting it cleanly reserves
the name for the future in-place overlay (#294). The validation error
names `'unified'`, so anyone tracking `main` is pointed at the new
value.
- **Internal names kept.** The `diff_inline.lua` module, its functions,
the `claudecode_inline_diff` buffer variable, and the
`ClaudeCodeInlineDiff*` highlight groups are unchanged — they describe
the inline-*style* rendering, not the layout value (#293 noted the
buffer var can stay). This keeps the diff small and low-risk.
- **#279 changelog** regenerates from commits via Communique on the next
push to `main`, so the v0.4.0 entry reflects "unified" automatically; I
did not hand-edit the bot branch.

## Validation

- `mise run all`: treefmt clean, luacheck **0/0**, **703/703** tests
pass (baseline 702 + the new rejection test).
- Headless Neovim smoke test: `layout = "unified"` accepted, `"inline"`
rejected (error names `'unified'`), `"vertical"` still works.

The true in-place overlay (the future `"inline"`) is tracked in #294.

Refs #293, #195, #82

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Signed-off-by: Thomas Kosiewski <tk@coder.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ThomasK33

CHANGELOG.md

@@ -8,6 +8,7 @@
 - `:ClaudeCodeCloseAllDiffs` command to close pending Claude diffs at once (e.g. proposals orphaned by resolving them via Claude remote control). Diffs you have already accepted but whose file has not been written yet are left intact so saved edits are never discarded. ([#248](https://github.com/coder/claudecode.nvim/issues/248))
 - `:ClaudeCodeSendText {text}` command (and `require("claudecode.terminal").send_to_terminal(text, opts)` function) to send arbitrary text to the open Claude terminal as if typed at the prompt, submitting it by default. `:ClaudeCodeSendText!` inserts the text without submitting. Handy for scripting and keymaps; multi-line text is sent via bracketed paste. Works with the in-editor `native`/`snacks` providers only — `external`/`none` run Claude outside Neovim, where there is no pane to write to. ([#197](https://github.com/coder/claudecode.nvim/issues/197))
 - `terminal.auto_insert` option (default `true`) controlling whether the Claude terminal auto-enters insert/terminal mode when its window gains focus. With the default Snacks provider, switching back into the terminal window (e.g. `<C-w>l`) previously re-entered terminal mode and jumped to the bottom prompt, discarding your Normal-mode scroll/reading position; set `auto_insert = false` to stay in Normal mode and preserve the scroll position (press `i` to type). Applies to the `native` and `snacks` providers and the new-tab diff terminal. ([#232](https://github.com/coder/claudecode.nvim/issues/232), [#145](https://github.com/coder/claudecode.nvim/issues/145))
+- `diff_opts.layout = "unified"`: a unified diff rendered in a single buffer with deleted (red/strikethrough) and added (green) lines interleaved, as a compact alternative to the two-pane `"vertical"`/`"horizontal"` layouts. Requires Neovim >= 0.9.0; the `ClaudeCodeInlineDiffAdd`/`Delete`/`AddSign`/`DeleteSign` highlight groups are customizable. ([#82](https://github.com/coder/claudecode.nvim/issues/82), [#195](https://github.com/coder/claudecode.nvim/pull/195), [#293](https://github.com/coder/claudecode.nvim/issues/293))
 
 ### Bug Fixes
 

README.md

@@ -376,8 +376,8 @@ For deep technical details, see [ARCHITECTURE.md](./ARCHITECTURE.md).
 
     -- Diff Integration
     diff_opts = {
-      layout = "vertical", -- "vertical" (default), "horizontal", or "inline"
-      -- "inline": VS Code-style unified diff in a single buffer with deleted
+      layout = "vertical", -- "vertical" (default), "horizontal", or "unified"
+      -- "unified": VS Code-style unified diff in a single buffer with deleted
       --   (red/strikethrough) and added (green) lines interleaved. Requires
       --   Neovim >= 0.9.0. Highlight groups are customizable: ClaudeCodeInlineDiffAdd,
       --   ClaudeCodeInlineDiffDelete, ClaudeCodeInlineDiffAddSign, ClaudeCodeInlineDiffDeleteSign.

lua/claudecode/config.lua

@@ -132,8 +132,8 @@ function M.validate(config)
     assert(
       config.diff_opts.layout == "vertical"
         or config.diff_opts.layout == "horizontal"
-        or config.diff_opts.layout == "inline",
-      "diff_opts.layout must be 'vertical', 'horizontal', or 'inline'"
+        or config.diff_opts.layout == "unified",
+      "diff_opts.layout must be 'vertical', 'horizontal', or 'unified'"
     )
   end
   if config.diff_opts.open_in_new_tab ~= nil then

lua/claudecode/diff.lua

@@ -838,8 +838,8 @@ function M._resolve_diff_as_saved(tab_name, buffer_id)
     return
   end
 
-  -- Dispatch to inline diff handler
-  if diff_data.layout == "inline" then
+  -- Dispatch to unified diff handler
+  if diff_data.layout == "unified" then
     local inline = require("claudecode.diff_inline")
     inline.resolve_inline_as_saved(tab_name, diff_data)
     return
@@ -932,8 +932,8 @@ function M._resolve_diff_as_rejected(tab_name)
     return
   end
 
-  -- Dispatch to inline diff handler
-  if diff_data.layout == "inline" then
+  -- Dispatch to unified diff handler
+  if diff_data.layout == "unified" then
     local inline = require("claudecode.diff_inline")
     inline.resolve_inline_as_rejected(tab_name, diff_data)
     return
@@ -1166,8 +1166,8 @@ function M._cleanup_diff_state(tab_name, reason)
     return
   end
 
-  -- Dispatch to inline diff handler
-  if diff_data.layout == "inline" then
+  -- Dispatch to unified diff handler
+  if diff_data.layout == "unified" then
     local inline = require("claudecode.diff_inline")
     inline.cleanup_inline_diff(tab_name, diff_data)
     active_diffs[tab_name] = nil
@@ -1315,8 +1315,8 @@ function M._setup_blocking_diff(params, resolution_callback)
       end
     end
 
-    -- Dispatch to inline diff if configured
-    if config and config.diff_opts and config.diff_opts.layout == "inline" then
+    -- Dispatch to unified diff if configured
+    if config and config.diff_opts and config.diff_opts.layout == "unified" then
       local inline = require("claudecode.diff_inline")
       inline.setup_inline_diff(params, resolution_callback, config)
       return

lua/claudecode/diff_inline.lua

@@ -197,7 +197,7 @@ function M.setup_inline_diff(params, resolution_callback, config)
     error({ code = -32000, message = "Buffer creation failed", data = "Could not create inline diff buffer" })
   end
 
-  pcall(vim.api.nvim_buf_set_name, buf, tab_name .. " (inline diff)")
+  pcall(vim.api.nvim_buf_set_name, buf, tab_name .. " (unified diff)")
   vim.api.nvim_buf_set_option(buf, "buftype", "acwrite")
   vim.api.nvim_buf_set_option(buf, "bufhidden", "wipe")
 
@@ -330,7 +330,7 @@ function M.setup_inline_diff(params, resolution_callback, config)
     })
   end
 
-  -- Register state with layout = "inline"
+  -- Register state with layout = "unified"
   diff._register_diff_state(tab_name, {
     old_file_path = params.old_file_path,
     new_file_path = params.new_file_path,
@@ -345,7 +345,7 @@ function M.setup_inline_diff(params, resolution_callback, config)
     status = "pending",
     resolution_callback = resolution_callback,
     result_content = nil,
-    layout = "inline",
+    layout = "unified",
     -- Track the originating MCP client so close_diffs_for_client can tear this
     -- diff down if that client disconnects (parity with the native path, #261).
     client_id = params.client_id,

lua/claudecode/types.lua

@@ -31,7 +31,7 @@
 ---@alias ClaudeCodeLogLevel "trace"|"debug"|"info"|"warn"|"error"
 
 -- Diff layout type alias
----@alias ClaudeCodeDiffLayout "vertical"|"horizontal"|"inline"
+---@alias ClaudeCodeDiffLayout "vertical"|"horizontal"|"unified"
 
 -- Behavior when rejecting new-file diffs
 ---@alias ClaudeCodeNewFileRejectBehavior "keep_empty"|"close_window"

tests/unit/diff_inline_spec.lua

@@ -327,7 +327,7 @@ describe("Inline diff module", function()
   end)
 
   describe("config validation", function()
-    it("should accept layout = 'inline'", function()
+    it("should accept layout = 'unified'", function()
       package.loaded["claudecode.config"] = nil
       package.loaded["claudecode.terminal"] = nil
       -- Stub terminal module with defaults
@@ -347,8 +347,8 @@ describe("Inline diff module", function()
         ensure_visible = function() end,
       }
       local config = require("claudecode.config")
-      local applied = config.apply({ diff_opts = { layout = "inline" } })
-      assert.are.equal("inline", applied.diff_opts.layout)
+      local applied = config.apply({ diff_opts = { layout = "unified" } })
+      assert.are.equal("unified", applied.diff_opts.layout)
     end)
 
     it("should reject invalid layout values", function()
@@ -374,7 +374,33 @@ describe("Inline diff module", function()
         config.apply({ diff_opts = { layout = "invalid" } })
       end)
       assert.is_false(success)
-      assert_contains(tostring(err), "inline")
+      assert_contains(tostring(err), "'unified'")
+    end)
+
+    it("should reject the former layout = 'inline' (renamed to 'unified')", function()
+      package.loaded["claudecode.config"] = nil
+      package.loaded["claudecode.terminal"] = nil
+      package.loaded["claudecode.terminal"] = {
+        defaults = {
+          split_side = "right",
+          split_width_percentage = 0.30,
+          provider = "auto",
+          show_native_term_exit_tip = true,
+          auto_close = true,
+          env = {},
+          snacks_win_opts = {},
+        },
+        get_active_terminal_bufnr = function()
+          return nil
+        end,
+        ensure_visible = function() end,
+      }
+      local config = require("claudecode.config")
+      local success, err = pcall(function()
+        config.apply({ diff_opts = { layout = "inline" } })
+      end)
+      assert.is_false(success)
+      assert_contains(tostring(err), "'unified'")
     end)
   end)