Re: [PATCH v2] ws: add new tab-between-non-ws check

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 7, 2026, 02:12 UTC
Message-ID: <xmqqsecii327.fsf@gitster.g>
In-Reply-To: <20260107013051.312291-1-adrian.ratiu@collabora.com>

Adrian Ratiu <adrian.ratiu@collabora.com> writes:

Show 7 quoted lines

> The check is a bit complex because we want to detect places where
> a SP was intended (HT can expand to more than one display column),
> so we need to count both the display columns (col) and the string
> character columns (i) to determine if a HT looks identical to a SP
> or can cause confusion.
>
> +/....adoc text eol=lf whitespace=trail,space,incomplete,tab-between-non-ws

The name of the whitespace rule does not quite match what we want to catch. Can somebody find a phrasing than "between non-ws" that conveys our intent better? We want to catch a tab that is used by mistsake when the writer would have used a space, and "between non-ws" is one of the heuristics (another is "it is at the 7th column to make it indistinguishable from a space") the code uses to tell if a tab is such a mistaken tab. "tab-instead-of-space"? "tab-in-place-of-space"? "tab-that-should-have-been-a-space"?

The last one is horrible and not a serious suggestion, of course.

> +test_expect_success 'check tab between non-whitespace (tab-between-non-ws: off)' '
> +	git config core.whitespace "-tab-between-non-ws" &&
> +
> +	printf "1234567\tb" >x &&

I notice all these printf create incomplete lines. It is true that the detection of a tab that is used when it should have been a space should work even on an incomplete line, but using an incomplete line, which is of course rather unusual, for these tests gives a false impression that somehow this requires an incomplete line to trigger, which is not what we want to give.

	printf "1234567\tb\n" > x &&

or something, perhaps?  I dunno.