lua: add {old_byte_size} to on_lines buffer change event

test/functional/lua/buffer_updates_spec.lua

@@ -5,6 +5,8 @@ local command = helpers.command
 local meths = helpers.meths
 local clear = helpers.clear
 local eq = helpers.eq
+local exec_lua = helpers.exec_lua
+local feed = helpers.feed
 
 local origlines = {"original line 1",
                    "original line 2",
@@ -16,7 +18,7 @@ local origlines = {"original line 1",
 describe('lua: buffer event callbacks', function()
   before_each(function()
     clear()
-    meths.execute_lua([[
+    exec_lua([[
       local events = {}
 
       function test_register(bufnr, id, changedtick)
@@ -38,55 +40,101 @@ describe('lua: buffer event callbacks', function()
         events = {}
         return ret_events
       end
-    ]], {})
+    ]])
   end)
 
-  it('works', function()
+
+  -- verifying the sizes with nvim_buf_get_offset is nice (checks we cannot
+  -- assert the wrong thing), but masks errors with unflushed lines (as
+  -- nvim_buf_get_offset forces a flush of the memline). To be safe run the
+  -- test both ways.
+  local function check(verify)
+    local lastsize
     meths.buf_set_lines(0, 0, -1, true, origlines)
-    meths.execute_lua("return test_register(...)", {0, "test1"})
+    if verify then
+      lastsize = meths.buf_get_offset(0, meths.buf_line_count(0))
+    end
+    exec_lua("return test_register(...)", 0, "test1")
     local tick = meths.buf_get_changedtick(0)
 
+    local verify_name = "test1"
+    local function check_events(expected)
+      local events = exec_lua("return get_events(...)" )
+      eq(expected, events)
+      if verify then
+        for _, event in ipairs(events) do
+          if event[1] == verify_name and event[2] == "lines" then
+            local startline, endline = event[5], event[7]
+            local newrange = meths.buf_get_offset(0, endline) - meths.buf_get_offset(0, startline)
+            local newsize = meths.buf_get_offset(0, meths.buf_line_count(0))
+            local oldrange = newrange + lastsize - newsize
+            eq(oldrange, event[8])
+            lastsize = newsize
+          end
+        end
+      end
+    end
+
     command('normal! GyyggP')
     tick = tick + 1
-    eq({{ "test1", "lines", 1, tick, 0, 0, 1 }},
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test1", "lines", 1, tick, 0, 0, 1, 0}})
 
     meths.buf_set_lines(0, 3, 5, true, {"changed line"})
     tick = tick + 1
-    eq({{ "test1", "lines", 1, tick, 3, 5, 4 }},
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test1", "lines", 1, tick, 3, 5, 4, 32 }})
 
-    meths.execute_lua("return test_register(...)", {0, "test2", true})
+    exec_lua("return test_register(...)", 0, "test2", true)
     tick = tick + 1
     command('undo')
 
     -- plugins can opt in to receive changedtick events, or choose
     -- to only recieve actual changes.
-    eq({{ "test1", "lines", 1, tick, 3, 4, 5 },
-        { "test2", "lines", 1, tick, 3, 4, 5 },
-        { "test2", "changedtick", 1, tick+1 } },
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test1", "lines", 1, tick, 3, 4, 5, 13 },
+        { "test2", "lines", 1, tick, 3, 4, 5, 13 },
+        { "test2", "changedtick", 1, tick+1 } })
     tick = tick + 1
 
     -- simulate next callback returning true
-    meths.execute_lua("test_unreg = 'test1'", {})
+    exec_lua("test_unreg = 'test1'")
 
     meths.buf_set_lines(0, 6, 7, true, {"x1","x2","x3"})
     tick = tick + 1
 
     -- plugins can opt in to receive changedtick events, or choose
     -- to only recieve actual changes.
-    eq({{ "test1", "lines", 1, tick, 6, 7, 9 },
-        { "test2", "lines", 1, tick, 6, 7, 9 }},
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test1", "lines", 1, tick, 6, 7, 9, 16 },
+        { "test2", "lines", 1, tick, 6, 7, 9, 16 }})
+
+    verify_name = "test2"
 
     meths.buf_set_lines(0, 1, 1, true, {"added"})
     tick = tick + 1
-    eq({{ "test2", "lines", 1, tick, 1, 1, 2 }},
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test2", "lines", 1, tick, 1, 1, 2, 0 }})
+
+    feed('wix')
+    tick = tick + 1
+    check_events({{ "test2", "lines", 1, tick, 4, 5, 5, 16 }})
+
+    -- check hot path for multiple insert
+    feed('yz')
+    tick = tick + 1
+    check_events({{ "test2", "lines", 1, tick, 4, 5, 5, 17 }})
+
+    feed('<bs>')
+    tick = tick + 1
+    check_events({{ "test2", "lines", 1, tick, 4, 5, 5, 19 }})
+
+    feed('<esc>')
 
     command('bwipe!')
-    eq({{ "test2", "detach", 1 }},
-       meths.execute_lua("return get_events(...)", {}))
+    check_events({{ "test2", "detach", 1 }})
+   end
+
+  it('works', function()
+    check(false)
+  end)
+
+  it('works with verify', function()
+    check(true)
   end)
 end)