Re: diff --check is stupid about blank lines

Jeff King [off-list ref] writes:

... The problem seems to be the conditional at
diff.c:1622:

        if ((data.ws_rule & WS_TRAILING_SPACE) &&
            data.trailing_blanks_start) {
                fprintf(o->file, "%s:%d: ends with blank lines.\n",
                        data.filename, data.trailing_blanks_start);
                data.status = 1; /* report errors */
        }

that should probably be "if we care about trailing space, and the last
thing we saw was a trailing blank, _and_ the last hunk adds to
end-of-file, then...".

Instead, data.trailing_blanks_start is supposed to be reset to 0 every
time we see non-blank newline, a copied context line, or new hunk.

So if this triggers with -U0 I'd understand, but otherwise I do not see
how.