2011/5/11 Chet Ramey <chet.ra...@case.edu>: > On 5/9/11 8:06 PM, Mårten Wikström wrote: > >> There are two problems/solutions here. The comment in the code above >> seems to indicate that the quotes should actually be thrown away as is >> done in 4.1. But on the other hand, word_list_remove_quoted_nulls() >> seems to indicate it should remove all nulls, not just the first. >> If I fix word_list_remove_quoted_nulls() to actually remove all >> consecutive nulls, the problem is >> solved. (At least my simple test-case works). If I revert the line >> above to the 4.1 version it also >> solves my problem. > > Unfortunately, that will not work. You can't throw away the empty strings > unless you're sure that you won't be performing word splitting. The best > example is > > f=" val" e= > echo "$e"$f > > which should result in two fields, the first of which is the empty string. > Bash-4.1 got that wrong.
Oh, I see. Thanks for pointing it out and for the illuminating example. >> >> Alas, my understanding of the bash code is fairly limited so my fixes >> will likely break something. Perhaps someone with a little more >> insight could tell the right(tm) solution. >> >> Anyway, here are the patches. >> Solution 1, fixing remove_quoted_nulls(): >> >> *** subst.c 2011-05-10 01:48:54.816322136 +0200 >> --- ../bash-4.2-patched/subst.c 2011-05-10 01:53:31.350806960 +0200 >> *************** remove_quoted_nulls (string) >> *** 3706,3712 **** >> break; >> } >> else if (string[i] == CTLNUL) >> ! i++; >> >> prev_i = i; >> ADVANCE_CHAR (string, slen, i); >> --- 3706,3713 ---- >> break; >> } >> else if (string[i] == CTLNUL) >> ! while (string[i] == CTLNUL) >> ! i++; >> >> prev_i = i; >> ADVANCE_CHAR (string, slen, i); > > It's the right place, but the wrong fix. The code as it reads in bash-4.2 > skips over each character immediately following a CTLNUL. If a sequence > of CTLNULs appear, it skips every other one. I attached a patch that does > the right thing. Ah, you are absolutely right. Thank you for the correction and the patch. Regards, Mårten
