Re: patch: do not emit trailing blanks in context header

[Paul Eggert]

Jim Meyering <address@hidden> writes:

> Do you mean that you *can* fix it for diff -u ?

I proposed a spec for diff -u requiring a trailing space to the POSIX
folks and it was accepted for draft 2 of the next version (see XCU ERN 103 in
<http://www.opengroup.org/austin/aardvark/latest/xcubug2.txt>)

We could try to get the spec updated.  I guess this wording:

    Each unaffected line shall be written in the following
    format:

    "^%s", <unaffected_line>

    where the contents of the unaffected line shall be taken from
    file1.

would be replaced by:

    Each nonempty unaffected line shall be written in the following
    format:

    "^%s", <unaffected_line>

    where the contents of the unaffected line shall be taken from
    file1.  Each empty unaffected line shall be written as either
    an empty line, or a line containing a single space character.

Do you think this change is worth pursuing?

All programs reading patches that I know of treat empty lines the same
as lines containing a single space, due to the usual problems of
stripping trailing white space, so I don't think this will pose much
of a hardship in real life.