Here is another patch that was pending.
Bash Version: 5.2
Commit 87a6e89edc7cb1af057e2c15666df189595d305b (the current devel)
Description:
When `shopt -s patsub_replacement' is turned on and the pattern
string `pat' of ${var/$pat/"&"} is just an anchoring character `#'
or `%', the internal escape of `&' (i.e., `\&') remains in the
result of the parameter expansion. Also, with the same condition,
the unquoted & in ${var/$pat/&} remains a literal & where we expect
it to be expanded to an empty string.
Repeat-By:
When `pat' contains non-anchoring characters, the expected result of
the expansions is obtained as
$ bash-dev --norc
$ shopt -s patsub_replacement
$ v=1234 pat=2; echo "${v/$pat/<&>}, ${v/$pat/<\&>}, ${v/$pat/"<&>"}"
1<2>34, 1<&>34, 1<&>34
$ v=1234 pat=#1; echo "${v/$pat/<&>}, ${v/$pat/<\&>}, ${v/$pat/"<&>"}"
<1>234, <&>234, <&>234
Here, unquoted & in the replacement is expanded to the matched
string as expected while quoted &'s are expanded to the literal `&'.
However, only when pat=# or pat=%, the result becomes
$ v=1234 pat=#; echo "${v/$pat/<&>}, ${v/$pat/<\&>}, ${v/$pat/"<&>"}"
<&>1234, <\&>1234, <\&>1234
where unquoted & does not become an empty string, and quoted &'s
become \&. In particular, with ${v/$pat/"<&>"}, a backslash
originally not present is inserted in the expanded result. I
instead expect the following result for consistency with the other
cases:
<>1234, <&>1234, <&>1234
Fix:
I attach a patch `r0031-fix-patsub.patch.txt'.
I guess the original intent of the related code has been to disable
patsub_replacement for ${var/#/...} and ${var/%/...} where the
pattern `# + <empty string>' or `% + <empty string>' is explicitly
specified (not through a parameter expansion $pat), but I would
still think we should keep the special treatment of unquoted & for
these cases as well when patsub_replacement is turned on for
consistency with other cases.
--
Koichi
From 3ff6e8b3fcb131676a7c7542b25d48b5768c8ea7 Mon Sep 17 00:00:00 2001
From: Koichi Murase <[email protected]>
Date: Mon, 24 Jan 2022 22:31:51 +0900
Subject: [PATCH 1/3] fix ${v/#PAT/"REP"}: process patsub_replacement also for
the special cases
---
subst.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/subst.c b/subst.c
index 163f42c1..666127c8 100644
--- a/subst.c
+++ b/subst.c
@@ -8930,36 +8930,38 @@ pat_subst (string, pat, rep, mflags)
* STRING and return the result.
* 3. A null STRING with a matching pattern means to append REP to
* STRING and return the result.
- * These don't understand or process `&' in the replacement string.
*/
if ((pat == 0 || *pat == 0) && (mtype == MATCH_BEG || mtype == MATCH_END))
{
- replen = STRLEN (rep);
+ if (mflags & MATCH_EXPREP)
+ rstr = strcreplace (rep, '&', "", 2);
+ else
+ rstr = rep;
+ rslen = STRLEN (rstr);
l = STRLEN (string);
- ret = (char *)xmalloc (replen + l + 2);
- if (replen == 0)
+ ret = (char *)xmalloc (rslen + l + 2);
+ if (rslen == 0)
strcpy (ret, string);
else if (mtype == MATCH_BEG)
{
- strcpy (ret, rep);
- strcpy (ret + replen, string);
+ strcpy (ret, rstr);
+ strcpy (ret + rslen, string);
}
else
{
strcpy (ret, string);
- strcpy (ret + l, rep);
+ strcpy (ret + l, rstr);
}
+ if (rstr != rep)
+ free (rstr);
return (ret);
}
else if (*string == 0 && (match_pattern (string, pat, mtype, &s, &e) != 0))
{
- replen = STRLEN (rep);
- ret = (char *)xmalloc (replen + 1);
- if (replen == 0)
- ret[0] = '\0';
+ if (mflags & MATCH_EXPREP)
+ return strcreplace (rep, '&', "", 2);
else
- strcpy (ret, rep);
- return (ret);
+ return savestring (rep);
}
ret = (char *)xmalloc (rsize = 64);
--
2.36.1
