bug#21167: 24.5; tags-search should ignore buffer restriction

[phs <phs@lsv.ens-cachan.fr>]

Description: tags-search when going through all files listed in the 
current tags table, tags-search searches inside existing buffers for 
files that are currently visited (this is where the latest version can 
be found).

But when the visiting buffer has been restricted by a narrow-to-region, 
tags-search will not look outside the narrowed-to scope.

I call this a bug. E.g., it can cause a global renaming of variables 
miss some occurrences. It seems that a minimal fix is for tags-search to 
warn the user that the buffer has been narrowed and offer to widen for 
the search (and maybe reinstall the restriction after the search???).


I looked at the source code. It appears that the problem is located 
within function next-file (in progmodes/etags.el). When it is found that 
there already is a buffer visiting the file to be searched for tags, 
next-file just uses it without checking for restrictions.

BTW, I don't understand why next-file passes the novisit flag to find-file?

-- 
Philippe SCHNOEBELEN,       	                  www.lsv.ens-cachan.fr/~phs
LSV, CNRS UMR 8643 & ENS de Cachan   		  Tel: (+33/0) 147 407 530
"Algebraic symbols are used when you do not know what you are talking about"