Discarding changes is not possible with a diff context size

Error message

Discarding changes is not possible with a diff context size of 0. Increase the context using '%s'.

What it means

StagingController.DiscardSelection (pkg/gui/controllers/staging_controller.go) discards the selected lines of the unstaged/staged diff; like ToggleStaged it hard-fails when git.diffContextSize is 0 because hunk reconstruction is impossible, returning NotEnoughContextToDiscard with the increase-context key hint.

Source

Thrown at pkg/gui/controllers/staging_controller.go:215

	if self.otherContext.GetState() != nil {
		self.c.Context().Push(self.otherContext, types.OnFocusOpts{})
	}

	return nil
}

func (self *StagingController) ToggleStaged() error {
	if self.c.UserConfig().Git.DiffContextSize == 0 {
		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextToStage,
			self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView)
	}

	return self.applySelectionAndRefresh(self.staged)
}

func (self *StagingController) DiscardSelection() error {
	if self.c.UserConfig().Git.DiffContextSize == 0 {
		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextToDiscard,
			self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView)
	}

	return self.c.ConfirmIf(!self.staged && !self.c.UserConfig().Gui.SkipDiscardChangeWarning,
		types.ConfirmOpts{
			Title:         self.c.Tr.DiscardChangeTitle,
			Prompt:        self.c.Tr.DiscardChangePrompt,
			HandleConfirm: func() error { return self.applySelectionAndRefresh(true) },
		})
}

func (self *StagingController) applySelectionAndRefresh(reverse bool) error {
	if err := self.applySelection(reverse); err != nil {
		return err
	}

	// Block input until the refresh has landed: it rebuilds the staging panel
	// and moves the selection to the next stageable change, and a quick second

View on GitHub (pinned to c477a2959b)

Solutions

Increase the diff context with '}' (default) and retry the discard.
Or persist git.diffContextSize >= 1 in the user config.
If discarding the whole file is acceptable, use the files-panel discard instead.

Example fix

# before (user config.yml)
git:
  diffContextSize: 0

# after
git:
  diffContextSize: 3

Defensive patterns

Strategy: validation

Validate before calling

if cfg.Git.DiffContextSize == 0 {
	return errors.New("raise git.diffContextSize before discarding selected lines")
}

Prevention

Raise context with '}' before destructive line-level discards.
Keep a non-zero default in the config to avoid surprises.

When it happens

Trigger: diffContextSize == 0 in the staging panel and the user presses the discard-selection key (default 'd') on selected lines; the check runs before the discard confirmation dialog.

Common situations: Same root cause as 157: zero-context diff preference colliding with line-level operations; especially surprising because discard is destructive and users expect the confirm dialog, not a config error.

Related errors

AI-assisted analysis of jesseduffield/lazygit@c477a2959b (2026-08-15). Data as JSON: /api/errors/5637bd42890b61f8. Report an issue: GitHub.