Subject: Re: [PATCH v2] diff: document -U without <n> as using default context

From: Oswald Buddenhagen <[email-masked]>
Date: Tue, 10 Mar 2026 10:15:58 +0100

On Tue, Mar 10, 2026 at 01:30:32PM +0800, Tian Yuchen wrote:
>The documentation for '-U<n>' implies that the numeric value '<n>' is
>mandatory. However, the command line parser has historically accepted
>'-U' without a number.
>
>Strictly requiring a number for '-U' would break existing tests
>(e.g., in 't4013') and likely disrupt user scripts relying on this
>undocumented behavior.

>Since we are retaining this fallback behavior for backward compatibility,
>update the documentation to explicitly state that '<n>' can be omitted
>for the short option '-U'.
>
i'd replace that with:

Hence we retain this fallback behavior for backward compatibility, but 
document it as such.

>+	(`-U` without `<n>` is accepted as a silent synonym for `-p` due
>+	to a historical accident).
> 
"silently accepted as a synonym" would be much more natural.