Steps to reproduce:
1. Run svn info --show-item=revision >out.txt
The file out.txt contains just the revision number and a newline.
The file out.txt contains the revision number, followed by some whitespaces and a newline.
The issue was passed on to the dev list here: http://mail-archives.apache.org/mod_mbox/subversion-dev/201610.mbox/%3C20161028184002.GA25363%40fujitsu.shahaf.local2%3E
Rational for this being a bug/unintended behavior:
1. One (if not the) main use-case for the newly introduced --show-item option is to make it easier to be used in scripts. For revisions, I used that to generate a revision range as in: -rXXX:YYY. XXX was retrieved using --show-item=revision. Since that produced unexpected trailing whitespaces the script command resulted in [...] -rXXX :YYY [...] which obviously caused an error message which was hard to debug since I didn't immediately get the idea that the trailing whitespaces might cause the script error I saw.
2. It's not what the documentation in the release notes state:
where it's explicitly shown that the reported revision number does not have any trailing whitespace:
Note: The issue was not present in SVN < 1.9, since the --show-item-option was added in SVN 1.9.0. Also I only tested it explicitly with SVN 1.9.4 but since the code change was introduced in 1.9.0 I'm quite certain the behavior exists in SVN 1.9.0-1.9.3 as well.