Vim-plug: random http failures

[anntzer]

:PlugUpdate randomly fails to access _some_ github repos over HTTPS:

- Finishing ... Done!
- vim-session: Already up-to-date.
x vim-stay
    fatal: unable to access 'https://github.com/kopischke/vim-stay.git/': Could not resolve host: github.com
- unite.vim: Already up-to-date.
- The-NERD-tree: Already up-to-date.
- tlib_vim: Already up-to-date.
- vim-cpp-enhanced-highlight: Already up-to-date.
x vifm.vim
    fatal: unable to access 'https://github.com/vifm/vifm.vim.git/': Could not resolve host: github.com

Relaunching :PlugUpdate typically results in a different random set of failures. Manually cloning from the terminal never fails, so it's not an internet connection issue.

:version
VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Jun  9 2016 09:35:51)
Included patches: 1-1910
Compiled by Arch Linux
Huge version with GTK2 GUI.  Features included (+) or not (-):
+acl             +cmdline_compl   +digraphs        +folding         +libcall         +mouse_dec       +netbeans_intg   +reltime         +tag_old_static  +vertsplit       -xfontset
+arabic          +cmdline_hist    +dnd             -footer          +linebreak       +mouse_gpm       +packages        +rightleft       -tag_any_white   +virtualedit     +xim
+autocmd         +cmdline_info    -ebcdic          +fork()          +lispindent      -mouse_jsbterm   +path_extra      +ruby/dyn        +tcl/dyn         +visual          +xsmp_interact
+balloon_eval    +comments        +emacs_tags      +gettext         +listcmds        +mouse_netterm   +perl/dyn        +scrollbind      +termguicolors   +visualextra     +xterm_clipboard
+browse          +conceal         +eval            -hangul_input    +localmap        +mouse_sgr       +persistent_undo +signs           +terminfo        +viminfo         -xterm_save
++builtin_terms  +cryptv          +ex_extra        +iconv           +lua/dyn         -mouse_sysmouse  +postscript      +smartindent     +termresponse    +vreplace        -xpm
+byte_offset     +cscope          +extra_search    +insert_expand   +menu            +mouse_urxvt     +printer         +startuptime     +textobjects     +wildignore
+channel         +cursorbind      +farsi           +job             +mksession       +mouse_xterm     +profile         +statusline      +timers          +wildmenu
+cindent         +cursorshape     +file_in_path    +jumplist        +modify_fname    +multi_byte      +python/dyn      -sun_workshop    +title           +windows
+clientserver    +dialog_con_gui  +find_in_path    +keymap          +mouse           +multi_lang      +python3/dyn     +syntax          +toolbar         +writebackup
+clipboard       +diff            +float           +langmap         +mouseshape      -mzscheme        +quickfix        +tag_binary      +user_commands   +X11
   system vimrc file: "/etc/vimrc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
  system gvimrc file: "/etc/gvimrc"
    user gvimrc file: "$HOME/.gvimrc"
2nd user gvimrc file: "~/.vim/gvimrc"
    system menu file: "$VIMRUNTIME/menu.vim"
  fall-back for $VIM: "/usr/share/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_GTK  -pthread -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/
include/pixman-1 -I/usr/include/libdrm -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/pango-1.0 -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/i
nclude/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -D_FORTIFY_SOURCE=2  -march=x8
6-64 -mtune=generic -O2 -pipe -fstack-protector-strong -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -L. -Wl,-O1,--sort-common,--as-needed,-z,relro -fstack-protector -rdynamic -Wl,-export-dynamic -Wl,-E -Wl,-rpath,/usr/lib/perl5/core_perl/CORE  -Wl,-O1,--sort-common,--as-needed,-z,rel
ro -L/usr/local/lib -Wl,--as-needed -o vim   -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 -lpango-1.0 -lgobject-2.0 -lglib-2.0 -lfontconfig
 -lfreetype -lSM -lICE -lXt -lX11 -lXdmcp -lSM -lICE  -lm -lncurses -lelf -lnsl    -lacl -lattr -lgpm -ldl   -Wl,-E -Wl,-rpath,/usr/lib/perl5/core_perl/CORE -Wl,-O1,--sort-common,--as-needed,-z,relro
 -fstack-protector-strong -L/usr/local/lib  -L/usr/lib/perl5/core_perl/CORE -lperl -lpthread -lnsl -ldl -lm -lcrypt -lutil -lc   -L/usr/lib -ltclstub8.6 -ldl -lz -lpthread -lieee -lm

• Type:
  
  
  
  • [X] Bug
  
  
  • [ ] Enhancement
  
  
  • [ ] Feature Request
  
  
  • [ ] Question
  
  
• OS:
  
  
  
  • [ ] All/Other
  
  
  • [X] Linux
  
  
  • [ ] OS X
  
  
  • [ ] Windows
  
  
• Vim:
  
  
  
  • [X] Terminal Vim
  
  
  • [X] GVim
  
  
  • [ ] Neovim
  
  

[junegunn]

vim-plug starts 16 concurrent git processes by default and my guess is that your internet connection is unable to handle them for some reason. Check if using smaller number of concurrent processes helps the situation. :PlugUpdate8, :PlugUpdate4, or even :PlugUpdate2 (I would also see if the problem is easily reproducible with more concurrency; :PlugUpdate99). If it helps, you can set up g:plug_threads so that you don't have to type in the number every time.

[anntzer]

Indeed, going down to 8 threads solved the problem (and everything does blow up with 99 threads).