fix(vim.net): filetype detection, mark unmodified #36297

Problem:
When running ":edit <url>", filetype detection is not triggered.

Solution:
Run the autocmds in the filetypedetect group after loading the content.

Problem:
After fetching remote content from a URL and adding it to the buffer,
the buffer is marked as modified. This is inconsistent with the original
netrw behavior, and it causes problems with `:e` to refresh or `:q` as
it prompts for saving the file even if the user hasn't touched the
content at all.

Solution:
Mark the buffer as unmodified right after adding the remote content to
the buffer.

runtime/plugin/nvim/net.lua

@@ -28,6 +28,8 @@ local function on_remote_read(args)
 
       local lines = vim.split(content.body, '\n', { plain = true })
       vim.api.nvim_buf_set_lines(bufnr, 0, -1, true, lines)
+      vim.api.nvim_exec_autocmds('BufRead', { group = 'filetypedetect', buffer = bufnr })
+      vim.bo[bufnr].modified = false
 
       vim.fn.winrestview(view)
       vim.api.nvim_echo({ { 'Loaded ' .. url, 'Normal' } }, true, {})

test/functional/lua/net_spec.lua

@@ -39,6 +39,37 @@ describe('vim.net.request', function()
     )
   end)
 
+  it('detects filetype for remote content', function()
+    t.skip(skip_integ, 'NVIM_TEST_INTEG not set: skipping network integration test')
+
+    local ft = exec_lua([[
+      vim.cmd('runtime! plugin/nvim/net.lua')
+      vim.cmd('runtime! filetype.lua')
+      -- github raw dump of a small lua file in the neovim repo
+      vim.cmd('edit https://raw.githubusercontent.com/neovim/neovim/master/runtime/syntax/tutor.lua')
+      vim.wait(2000, function() return vim.bo.filetype ~= '' end)
+      return vim.bo.filetype
+    ]])
+
+    assert(ft == 'lua', 'Expected filetype to be "lua", got: ' .. tostring(ft))
+  end)
+
+  it('removes the modified flag from the buffer for remote content', function()
+    t.skip(skip_integ, 'NVIM_TEST_INTEG not set: skipping network integration test')
+
+    local buffer_modified = exec_lua([[
+      vim.cmd('runtime! plugin/nvim/net.lua')
+      vim.cmd('runtime! filetype.lua')
+      vim.cmd('edit https://raw.githubusercontent.com/neovim/neovim/master/runtime/syntax/tutor.lua')
+      -- wait for buffer to have content
+      vim.wait(2000, function() return vim.fn.wordcount().bytes > 0 end)
+      vim.wait(2000, function() return vim.bo.modified == false end)
+      return vim.bo.modified
+    ]])
+
+    assert(not buffer_modified, 'Expected buffer to be unmodified for remote content')
+  end)
+
   it('calls on_response with error on 404 (async failure)', function()
     t.skip(skip_integ, 'NVIM_TEST_INTEG not set: skipping network integration test')
     local err = exec_lua([[