nickson@comp.vuw.ac.nz (Ray Nickson) (09/04/89)
The following bug which I reported in version 1.02 does not seem to have
gone away in 1.03.
From: Ray Nickson <nickson@COMP.VUW.AC.NZ>
Date: Tue, 08 Aug 89 16:20:36 +1200
There is a bug in glob.c (bash version 1.02, gcc-compiled, on an hp300
running more/bsd) which causes the following behaviour. Switch to a
directory containing only the files A and BC, then do echo *[^C]
I (usually) get both files listed. (my understanding is that BC
shouldn't be listed).
The problem is (not surprisingly) in the glob_match function in
glob.c; when matching against *<something>, we try to see how much of
our text <something> matches, and make * match enough to make this
work. So, we first attempt to match [^C] to BC; this fails because
[^C] must match exactly one character. Matching [^C] to C fails,
because it cannot match a C. But then, we try to match [^C] against
the null string; the code as written will test the first character of
the null string ('\0') against each element of the set (i.e. C); it
won't match, so we claim that "" matches [^C].
The easiest solution is probably to special-case the null string in
text being matched against a set, as we do when matching against ?.
-rgn
--
Ray Nickson, Dept. Comp. Sci., Victoria University of Wellington, New Zealand.
nickson@comp.vuw.ac.nz ...!uunet!vuwcomp!nickson + 64 4 721000x8593srg@quick.COM (Spencer Garrett) (09/08/89)
In article <8909040114.AA21411@comp.vuw.ac.nz>, nickson@comp.vuw.ac.nz (Ray Nickson) writes:
-> The problem is (not surprisingly) in the glob_match function in
-> glob.c; when matching against *<something>, we try to see how much of
-> our text <something> matches, and make * match enough to make this
-> work. So, we first attempt to match [^C] to BC; this fails because
-> [^C] must match exactly one character. Matching [^C] to C fails,
-> because it cannot match a C. But then, we try to match [^C] against
-> the null string; the code as written will test the first character of
-> the null string ('\0') against each element of the set (i.e. C); it
-> won't match, so we claim that "" matches [^C].
->
-> The easiest solution is probably to special-case the null string in
-> text being matched against a set, as we do when matching against ?.
Argh! The code should remember where the end of the string is, and
not try to special case some magic character. The comparison should
always fail if you're at the end of the string, but not at the end of
the pattern.