is your /usr/share/info/dir in perfect shape?
Gentlemen, the Info dir on my system is not in tip top shape, and may
not be also on yours. Try this simple test for duplicate entries:
$ sort /usr/share/info/dir|uniq -d|fgrep \*
* patch: (diff)Invoking patch. Apply a patch to a file.
* sdiff: (diff)Invoking sdiff. Merge 2 files
* testsuite: (autoconf)testsuite Invocation. Running an Autotest test
So some packages are using install-info imperfectly.
Maybe instead of relying on perfect use of install-info by each
package, perhaps just remaking /usr/share/info/dir from whatever info
files are on the system might be less error prone?
$ sed -n 's/:.*//p' dir|sort|uniq -d
for me reveals that I need to do
$ install-info --remove /usr/share/info/sh-utils.info
as apparently that wasn't done when those tools were moved to a
different package. Same with fileutils...