feat(diff): apply all code blocks for a file at once when showing diff

lua/CopilotChat/config/mappings.lua

@@ -172,9 +172,10 @@ return {
 
       local path = block.header.filename
       local bufnr = prepare_diff_buffer(path, source)
-      local new_lines = diff.apply_diff(block, bufnr)
+      local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+      local new_lines = diff.apply_diff(block, lines)
       vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, new_lines)
-      local first, last = diff.get_diff_region(block, bufnr)
+      local first, last = diff.get_diff_region(block, lines)
       if first and last then
         select.set(bufnr, source.winnr, first, last)
         select.highlight(bufnr)
@@ -192,7 +193,8 @@ return {
 
       local path = block.header.filename
       local bufnr = prepare_diff_buffer(path, source)
-      local first, last = diff.get_diff_region(block, bufnr)
+      local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+      local first, last = diff.get_diff_region(block, lines)
       if first and last and bufnr then
         select.set(bufnr, source.winnr, first, last)
         select.highlight(bufnr)
@@ -223,7 +225,25 @@ return {
 
       local path = block.header.filename
       local bufnr = prepare_diff_buffer(path, source)
-      local new_lines = diff.apply_diff(block, bufnr)
+
+      -- Collect all blocks for the same filename
+      local message = copilot.chat:get_message(constants.ROLE.ASSISTANT, true)
+      local blocks = {}
+      if message and message.section and message.section.blocks then
+        for _, b in ipairs(message.section.blocks) do
+          if b.header.filename == path then
+            table.insert(blocks, b)
+          end
+        end
+      else
+        blocks = { block }
+      end
+
+      -- Apply all diffs for the filename
+      local new_lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+      for i = #blocks, 1, -1 do
+        new_lines = diff.apply_diff(blocks[i], new_lines)
+      end
 
       local opts = {
         filetype = vim.bo[bufnr].filetype,

lua/CopilotChat/utils/diff.lua

@@ -120,8 +120,8 @@ function M.apply_unified_diff(diff_text, original_content)
     new_content = patched
     applied = applied or ok
   end
-  local original_lines = vim.split(original_content, '\n')
-  local new_lines = vim.split(new_content, '\n')
+  local original_lines = vim.split(original_content, '\n', { trimempty = true })
+  local new_lines = vim.split(new_content, '\n', { trimempty = true })
   local first, last
   local max_len = math.max(#original_lines, #new_lines)
   for i = 1, max_len do
@@ -137,10 +137,9 @@ end
 
 --- Get diff from block content and buffer lines
 ---@param block CopilotChat.ui.chat.Block Block containing diff info
----@param bufnr integer Buffer number
+---@param lines table table of lines
 ---@return string diff, string content
-function M.get_diff(block, bufnr)
-  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+function M.get_diff(block, lines)
   local content = table.concat(lines, '\n')
   if block.header.filetype == 'diff' then
     return block.content, content
@@ -161,18 +160,18 @@ function M.get_diff(block, bufnr)
     vim.diff(
       table.concat(original_lines, '\n'),
       table.concat(patched_lines, '\n'),
-      { algorithm = 'myers', ctxlen = 20, interhunkctxlen = 50, ignore_whitespace_change = true }
+      { algorithm = 'myers', ctxlen = 10, interhunkctxlen = 10, ignore_whitespace_change = true }
     )
   ),
     content
 end
 
 --- Apply a diff (unified or indices) to buffer lines
 ---@param block CopilotChat.ui.chat.Block Block containing diff info
----@param bufnr integer Buffer number
+---@param lines table table of lines
 ---@return table new_lines
-function M.apply_diff(block, bufnr)
-  local diff, content = M.get_diff(block, bufnr)
+function M.apply_diff(block, lines)
+  local diff, content = M.get_diff(block, lines)
   local new_lines, applied, _, _ = M.apply_unified_diff(diff, content)
   if not applied then
     log.debug('Diff for ' .. block.header.filename .. ' failed to apply cleanly for:\n' .. diff)
@@ -183,10 +182,10 @@ end
 
 --- Get changed region for diff (unified or indices)
 ---@param block CopilotChat.ui.chat.Block Block containing diff info
----@param bufnr integer Buffer number
+---@param lines table table of lines
 ---@return number? first, number? last
-function M.get_diff_region(block, bufnr)
-  local diff, content = M.get_diff(block, bufnr)
+function M.get_diff_region(block, lines)
+  local diff, content = M.get_diff(block, lines)
   local _, _, first, last = M.apply_unified_diff(diff, content)
   return first, last
 end

tests/diff_spec.lua

@@ -179,7 +179,7 @@ describe('CopilotChat.utils.diff', function()
     local original_content = table.concat(original, '\n')
     local result, applied = diff.apply_unified_diff(diff_text, original_content)
     assert.is_true(applied)
-    assert.are.same({ '' }, result)
+    assert.are.same({}, result)
   end)
 
   it('applies unified diff with all lines added to empty file', function()