Hi Junio,

On Mon, 29 Aug 2022, Junio C Hamano wrote:

Johannes Schindelin [off-list ref] writes:

quoted

Here is why: in the _regular_ case, i.e. when we have a colored hunk
header like `@@ -936 +936 @@ wow()`, we manage to parse the line range,
and then record the offset of the extra part that starts afterwards.

This extra part is non-empty, therefore we add an extra space.

But that part already starts with a space, so now we end up with two
spaces.

In other words, this breaks because the original code depended on
having the extra whitespace before the "funcname" part.

Yes.

Stepping back a bit, if the final goal for the UI generation out of
this string is to append the material with a whitespace before it
for better visual separation, then the original should probably have
(at least conceptually) lstrip'ed the leading whitespaces from the
string it found after " @@" and then appended the result to where it
is showing, with its own single whitespace as a prefix.

Yes, with one twist: ANSI escape sequences can make lstrip'ing non-trivial
(granted, the line range parser totally ignores the fact that `@@<RESET> `
is a totally legitimate end of a colored line range).

It would have prevented this bug from happening by future-proofing, and
made the final output nicer, as any excess whitespaces between the " @@"
and "funcname" would have been turned into a single SP.

The "prepend one iff it does not already begin with a whitespace" is
a (at least mentally to the developer) less expensive approach that
is fine, too.

Yes, it is definitely less expensive.

Ciao,
Dscho