I implemented an option in the standalone Info browser to search the subdirectory containing the current Info file when following a cross-reference to another manual, before searching through the Info file search path. Emacs Info could have a similar option.
The variable is called "follow-strategy": in Emacs the variable could be "Info-follow-strategy". The two possible values at the moment are "remain" and "path". "remain" is the default: it means to try to remain in the current subdirectory. The other is "path" which means search through the search path, which was the previous default behaviour. If you can think of better names please email. The intention behind this change is to improve support for installation of multiple versions of manuals at once. For example, with a dir entry of * Emacs-23: (emacs-23/emacs)Top. and with files emacs-23/emacs.info, emacs-23/calc.info doing "info Emacs-23" gives the emacs-23/emacs.info file. Then following a cross-reference "*Note (calc)Top::." will find emacs-23/calc.info, instead of whatever calc.info file was earlier in the search path. Likewise there can be other subdirectories under the main Info subdirectory for other versions, like "emacs-24" or "emacs-25", containing the corresponding Info files. This should be useful for projects like Emacs with many manuals that all reference each other, and when finding the manual for the same version is desirable. This appears to provide the functionality that some users wanted, for example the Debian maintainers. However, let me point out what this doesn't accomplish: * References to the "emacs" manual from outwith the "emacs-23" subdirectory will not be capable of finding "emacs-23/emacs.info", unless "emacs-23" is in the search path. * Such dir entries cannot at present be automatically generated by appropriately invoking install-info (the program to update dir files), or by Automake-generated build systems that install Info files. So there still isn't a convenient way to install and access multiple versions of Info manuals at once. * References to subdirectories in node specifications aren't treated the way they need to be for this to work by the Info browser from the Texinfo 6.0 release; this has been changed since then in the development sources. Please email bug-texinfo@gnu.org with any suggestions that could be useful for the Texinfo project. Eli Zaretskii asked me to file this bug report. I emailed bug-gnu-emacs because M-x report-emacs-bug isn't set up to send emails for me.
