Comment block disappears

[miguelmota]

Describe the bug
Inplace writing is deleting comment blocks

version of yq: 3.3.2
operating system: Linux archlinux 5.4.36-1-lts #1 SMP Wed, 29 Apr 2020 16:23:03 +0000 x86_64 GNU/Linux

Input Yaml
Concise yaml document(s) (as simple as possible to show the bug)
data1.yml:

(Removed by Mike - too long)

[mikefarah]

Can you please provide a small example of yaml - I can't make sense of this

[miguelmota]

~/.config/alacritty/alacritty.yml

background_opacity: 0.6

key_bindings:
  # (Windows/Linux only)
  #- { key: V,        mods: Control|Shift, action: Paste            }
  #- { key: C,        mods: Control|Shift, action: Copy             }
  #- { key: Insert,   mods: Shift,         action: PasteSelection   }
  #- { key: Key0,     mods: Control,       action: ResetFontSize    }
  #- { key: Equals,   mods: Control,       action: IncreaseFontSize }
  #- { key: Add,      mods: Control,       action: IncreaseFontSize }
  #- { key: Subtract, mods: Control,       action: DecreaseFontSize }
  #- { key: Minus,    mods: Control,       action: DecreaseFontSize }
  #- { key: Return,   mods: Alt,           action: ToggleFullscreen }

  # (macOS only)
  #- { key: Key0,   mods: Command,         action: ResetFontSize    }
  #- { key: Equals, mods: Command,         action: IncreaseFontSize }
  #- { key: Add,    mods: Command,         action: IncreaseFontSize }
  #- { key: Minus,  mods: Command,         action: DecreaseFontSize }
  #- { key: K,      mods: Command,         action: ClearHistory     }
  #- { key: K,      mods: Command,         chars: "\x0c"            }
  #- { key: V,      mods: Command,         action: Paste            }
  #- { key: C,      mods: Command,         action: Copy             }
  #- { key: H,      mods: Command,         action: Hide             }
  #- { key: Q,      mods: Command,         action: Quit             }
  #- { key: W,      mods: Command,         action: Quit             }
  #- { key: F,      mods: Command|Control, action: ToggleFullscreen }

  - { key: Paste,                   action: Paste                            }
  - { key: Copy,                    action: Copy                             }
  - { key: L,        mods: Control, action: ClearLogNotice                   }
  - { key: L,        mods: Control, chars: "\x0c"                            }

Command to run:

yq w -i ~/.config/alacritty/alacritty.yml background_opacity 1

Expected: only modify background_opacity property.

Actual: It deleted comments unexpectedly:

background_opacity: 1
key_bindings:
  # (macOS only)
  #- { key: Key0,   mods: Command,         action: ResetFontSize    }
  #- { key: Equals, mods: Command,         action: IncreaseFontSize }
  #- { key: Add,    mods: Command,         action: IncreaseFontSize }
  #- { key: Minus,  mods: Command,         action: DecreaseFontSize }
  #- { key: K,      mods: Command,         action: ClearHistory     }
  #- { key: K,      mods: Command,         chars: "\x0c"            }
  #- { key: V,      mods: Command,         action: Paste            }
  #- { key: C,      mods: Command,         action: Copy             }
  #- { key: H,      mods: Command,         action: Hide             }
  #- { key: Q,      mods: Command,         action: Quit             }
  #- { key: W,      mods: Command,         action: Quit             }
  #- { key: F,      mods: Command|Control, action: ToggleFullscreen }
  - {key: Paste, action: Paste}
  - {key: Copy, action: Copy}
  - {key: L, mods: Control, action: ClearLogNotice}
  - {key: L, mods: Control, chars: "\f"}

[mikefarah]

Played around with this, looks likes its an issue with the underlying yaml parser:

go-yaml/yaml#686

[mikefarah]

Note - as a (hacky) workaround if you remove or replace the empty line before key_binding, or the the empty line before the macOS comment - it seems to work. You could replace the empty line with an empty comment instead.

[miguelmota]

@mikefarah thanks for the tip, removing empty lines prevented them from being removed

[mikefarah]

Fixed in 4.3.0