Python's built-in unicodedata library includes the is_normalized()
function starting with Python 3.8. This utility function allows us
to do the same thing with earlier Python versions.
See: https://docs.python.org/3/library/unicodedata.html
This happens in names very often, for example in the contributor
and citation fields. I will limit this to those fields for now and
hide this fix behind the "unsafe fixes" option until I test it more.
Add a check for soft hyphens (U+00AD). In one sample CSV I have a
normal hyphen followed by a soft hyphen in an ISBN. This causes the
ISBN validation to fail.
This was tricky because of the nature of newlines. In actuality we
are removing Unix line feeds here (U+000A) because Windows carriage
returns are actually already removed by the string stripping in the
whitespace fix.
Creating the test case in Vim was difficult because I couldn't fig-
ure out how to manually enter a line feed character. In the end I
used a search and replace on a known pattern like "ALAN", replacing
it with \r. Neither entering the Unicode code point (U+000A) direc-
tly or typing an "Enter" character after ^V worked. Grrr.
These are things like non-breaking spaces, "replacement" characters,
etc that add nothing to the metadata and often cause errors during
parsing or displaying in a UI.
In this case it fixes occurences of invalid multi-value separators.
DSpace uses "||" to separate multiple values in one field, but our
editors sometimes give us files with mistakes like "|". We can fix
these to be correct multi-value separators if we are sure that the
metadata is not actually using "|" for some legitimate purpose.