API: emit nvim_buf_lines_event from :terminal #8616

closes #8575

src/nvim/terminal.c

@@ -1239,9 +1239,7 @@ static void refresh_screen(Terminal *term, buf_T *buf)
 
   int change_start = row_to_linenr(term, term->invalid_start);
   int change_end = change_start + changed;
-  changed_lines(change_start, 0, change_end, added,
-                // Don't send nvim_buf_lines_event for :terminal buffer.
-                false);
+  changed_lines(change_start, 0, change_end, added, true);
   term->invalid_start = INT_MAX;
   term->invalid_end = -1;
 }

test/functional/api/buffer_updates_spec.lua

@@ -3,6 +3,7 @@ local eq, ok = helpers.eq, helpers.ok
 local buffer, command, eval, nvim, next_msg = helpers.buffer,
   helpers.command, helpers.eval, helpers.nvim, helpers.next_msg
 local expect_err = helpers.expect_err
+local nvim_prog = helpers.nvim_prog
 local write_file = helpers.write_file
 
 local origlines = {"original line 1",
@@ -741,3 +742,88 @@ describe('API: buffer events:', function()
   end)
 
 end)
+
+describe('API: buffer events:', function()
+  before_each(function()
+    helpers.clear()
+  end)
+
+  local function lines_subset(first, second)
+    for i = 1,#first do
+      if first[i] ~= second[i] then
+        return false
+      end
+    end
+    return true
+  end
+
+  local function lines_equal(f, s)
+    return lines_subset(f, s) and lines_subset(s, f)
+  end
+
+  local function assert_match_somewhere(expected_lines, buffer_lines)
+    local msg = next_msg()
+
+    while(msg ~= nil) do
+      local event = msg[2]
+      if event == 'nvim_buf_lines_event' then
+        local args = msg[3]
+        local starts = args[3]
+        local newlines = args[5]
+
+        -- Size of the contained nvim instance is 23 lines, this might change
+        -- with the test setup. Note updates are continguous.
+        assert(#newlines <= 23)
+
+        for i = 1,#newlines do
+          buffer_lines[starts + i] = newlines[i]
+        end
+        -- we don't compare the msg area of the embedded nvim, it's too flakey
+        buffer_lines[23] = nil
+
+        if lines_equal(buffer_lines, expected_lines) then
+          -- OK
+          return
+        end
+      end
+      msg = next_msg()
+    end
+    assert(false, 'did not match/receive expected nvim_buf_lines_event lines')
+  end
+
+  it('when :terminal lines change', function()
+    local buffer_lines = {}
+    local expected_lines = {}
+    command('terminal "'..nvim_prog..'" -u NONE -i NONE -n -c "set shortmess+=A"')
+    local b = nvim('get_current_buf')
+    ok(buffer('attach', b, true, {}))
+
+    for _ = 1,22 do
+      table.insert(expected_lines,'~')
+    end
+    expected_lines[1] = ''
+    expected_lines[22] = ('tmp_terminal_nvim'..(' '):rep(45)
+                          ..'0,0-1          All')
+
+    sendkeys('i:e tmp_terminal_nvim<Enter>')
+    assert_match_somewhere(expected_lines, buffer_lines)
+
+    expected_lines[1] = 'Blarg'
+    expected_lines[22] = ('tmp_terminal_nvim [+]'..(' '):rep(41)
+                          ..'1,6            All')
+
+    sendkeys('iBlarg')
+    assert_match_somewhere(expected_lines, buffer_lines)
+
+    for i = 1,21 do
+      expected_lines[i] = 'xyz'
+    end
+    expected_lines[22] = ('tmp_terminal_nvim [+]'..(' '):rep(41)
+                          ..'31,4           Bot')
+
+    local s = string.rep('\nxyz', 30)
+    sendkeys(s)
+    assert_match_somewhere(expected_lines, buffer_lines)
+  end)
+
+end)