When review PR, diff view is not appear and `attempt to get length of field 'left_lines' (a nil value)` error occur

[yeonuk-hwang]

Issue Description

Type: bug report

Describe what happened (or what feature you want)

• when i open PR and review changes, sometimes the diff window does not open, and only loading view is opening(file view window location is octo/null)
• then, when i choose a file in file list, there is error

  
  E5108: Error executing lua ...e/nvim/plugged/octo.nvim/lua/octo/reviews/file-entry.lua:201: attempt to get length of field 'left_lines' (a nil value)
  stack traceback:
      ...e/nvim/plugged/octo.nvim/lua/octo/reviews/file-entry.lua:201: in function 'load_buffers'
      ...share/nvim/plugged/octo.nvim/lua/octo/reviews/layout.lua:146: in function 'set_file'
      ...local/share/nvim/plugged/octo.nvim/lua/octo/mappings.lua:159: in function <...local/share/nvim/plugged/octo.nvim/lua/octo/mappings.lua:154>
      ...local/share/nvim/plugged/octo.nvim/lua/octo/mappings.lua:9: in function 'on_keypress'
      [string ":lua"]:1: in main chunk

![image](https://user-images.githubusercontent.com/54208214/154192470-8b679cb3-3e0d-487f-a3ec-020a00ad3001.png)

### How to reproduce it (as minimally and precisely as possible)

1. `:Octo PR list` in project folder
2. `Octo review start` in PR

### Tell us your environment
- nvim v0.6.1
- use 'vim-plug' for plugin manager
here is my plugin list

Plug 'dracula/vim', { 'as': 'dracula' }
Plug 'tomasr/molokai' "color scheme
Plug 'leafgarland/typescript-vim' " TypeScript syntax
Plug 'jparise/vim-graphql'        " GraphQL syntax
Plug 'pangloss/vim-javascript' "javascript support
Plug 'maxmellon/vim-jsx-pretty'   " JS and JSX syntax
Plug 'styled-components/vim-styled-components', { 'branch': 'main' } "Styled-components Syntax
Plug 'neoclide/coc.nvim', {'branch': 'release'} "Intelignece
Plug 'vim-airline/vim-airline' "StatusBar
Plug 'vim-airline/vim-airline-themes' "StatusBar
Plug 'tpope/vim-fugitive' "Syntatic Sugar With Git 
Plug 'airblade/vim-gitgutter' "Git Column
Plug 'preservim/nerdtree' "File Explorer
Plug 'Xuyuanp/nerdtree-git-plugin' "Nerd Tree git diagnostic
Plug 'ryanoasis/vim-devicons' "NerdTree Icon Theme
Plug 'tiagofumo/vim-nerdtree-syntax-highlight' "NerdTree Highlight
Plug 'junegunn/fzf', { 'do': { -> fzf#install() } } "Fuzzy Finder
Plug 'junegunn/fzf.vim' "Fuzzy Finder
Plug 'stsewd/fzf-checkout.vim'
Plug 'tpope/vim-surround' "Add Surround Operator
Plug 'tpope/vim-repeat' "Advanced Dot operator
Plug 'tpope/vim-commentary' "Comment Easy
Plug 'alvan/vim-closetag' "Auto Close Tag
Plug 'AndrewRadev/tagalong.vim' "Change Tag Name both start and end"
Plug 'tpope/vim-eunuch' "UNIX Shell Commands Syntatic Sugar
Plug 'iamcco/markdown-preview.nvim', { 'do': 'cd app && yarn install'  }
Plug 'johngrib/vim-f-hangul'
Plug 'rust-lang/rust.vim'
Plug 'easymotion/vim-easymotion'
Plug 'mattn/emmet-vim'
Plug 'tamago324/vim-browsersync'
Plug 'tyru/open-browser.vim'
Plug 'kassio/neoterm'
Plug 'Yggdroot/indentLine'
Plug 'szw/vim-maximizer'
Plug 'junegunn/vim-easy-align'
Plug 'vim-test/vim-test'
Plug 'nvim-lua/plenary.nvim'
Plug 'nvim-telescope/telescope.nvim'
Plug 'kyazdani42/nvim-web-devicons'
Plug 'pwntester/octo.nvim'

### Anything else we need to know?
- when i open first pr and review them, it works well usually but, when i open second pr and review them, the above error occur
- when error is occured, I close the vim and reopen and try again, it works well

[pwntester]

Hi, thanks for reporting this! I was not able to reproduce it on PRs with small number of changed files (8). However, I got this error when trying a PR with many files (70). Was this also your case?

In my case, it seems like I get Post "https://api.github.com/graphql": net/http: TLS handshake timeout for many of the file requests.

Will try to figure out why Im getting this error

UPDATE: It seems like the problem is requesting too many files too quickly. Sleeping 1 sec between fetches gets rid of the issue. Need to check if this is a a rate limit problem

[pwntester]

@ younuk23 can you please check if latest version fixes the issue?

[taraslis453]

I am still getting this issue

[dlacaille]

I am having this issue as well, on nvim 0.6.1 running on a Mac. I am using Lunarvim but tried with NvChad as well, same error. The error also occurs on all of my projects. I simply can't jump forwards or backwards using [q or ]q.

[dlacaille]

@pwntester unfortunately I am not knowledgable enough to fix the issue but I can reproduce on my machine. Is there anything you might need to reproduce? Here is what might work:

1. Install nvim 0.6.1
2. Install LunarVim
3. Add the following to config.lua

   lvim.plugins = {
   {"pwntester/octo.nvim", config = function() require"octo".setup() end}
   }

4. :PackerSync
5. :Octo review start
6. ]q shows an error

If the issue is still not happening for you, I can try reproducing it on a docker container.

[pwntester]

@dlacaille this seems to be a different issue with the ]q, [q mappings. Please check if a2793a4c1814d27168686730cf2576915f9f556f fixes it for you

[dlacaille]

@pwntester the issue is still happening after updating:

[pwntester]

@dlacaille the stack trace seems to indicate that you are not using the latest version. Can you verify you are on the latest commit?

[taraslis453]

Fixed for me 👍

[dlacaille]

I tried again this morning and it seems to be working! Thank you :)