formats: fix splitting on non-spaces

GH #19985

formats have a mode where they can repeatedly split a string to fill
within a fixed text width, splitting on (by default), spaces, newlines
and hyphens.

The splitting code was heavily rewritten by me in
v5.19.5-218-g9b4bdfd44e, but in that patch I introduced a couple of
off-by-one errors when splitting on non-white-space characters (i.e. the
hyphen by default).

It turns out that splitting on a hyphen is completely untested in core,
and further, no one noticed the problems in the wild until this ticket,
8 years later!

The first issue, and the one in the bug report, is that when splitting,
the calculation for how many spaces to pad to the end of the field was
off by one, so:

    $v1 = "AB-CDE";

    format STDOUT =
    [^<<<]~~
    $v1
    .

    write;

gives:

    [AB-  ]
    [CDE ]

but should have given:

    [AB- ]
    [CDE ]

The second issue was that it was detecting a hyphen one character
further along than the maximum field length and still splitting it there:
as above, but

    $v1 = "ABCD-E";

gives:

    [ABCD-]
    [E   ]

but should have given:

    [ABCD]
    [-E  ]

The latter was because the non-space split code was using the same logic
as the split-on-space code, which is allowed to split on a space which
is one character beyond the maximum length.

This commit fixes both issues, and adds some tests.

0 files changed, 0 insertions, 0 deletions