hv at crypt
Dec 4, 2009, 7:29 AM
Post #1 of 2
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[PATCH] Re: [perl #71000] Wrong variable name in warning
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Abigail <abigail [at] abigail> wrote:
:On Wed, Dec 02, 2009 at 06:50:42AM -0800, mauzo [at] osiris (via RT) wrote:
:> ~/src/perl/perl% ./perl -we'my $x = 1; my $y = sprintf "%d" . $x'
:> Use of uninitialized value $x in sprintf at -e line 1.
:>
:> Note the typo: dot for comma.
:
:
:It's triggered by sprintf looking for a value to interpolate.
:Here's another way to trigger this bug:
:
: my $format = "%d"; my $y = sprintf $format;
I suggest the right thing is to emit a more specific warning in this case,
as per the patch below. But I doubt this is [important + safe] enough
to warrant applying during the feature freeze. With the patch applied:
zen% ./perl -we'my $x = 1; my $y = sprintf "%d" . $x'
Missing argument in sprintf at -e line 1.
zen% ./perl -we 'my $format = "%d"; my $y = sprintf $format'
Missing argument in sprintf at -e line 1.
zen%
As per the comment, I'm not sure if we'd want a new category for the new
warning. As written, it won't suddenly start warning where it didn't
before (which may or may not be a good thing).
I'm also not sure if the first change to t/op/sprintf2.t below is the best
approach. Apart from anything else, it should probably be changed to test
that sv_no (as well as/instead of sv_undef) is not getting corrupted.
This patch requires the patch to t/test.pl I sent earlier today.
Hugo
--- sv.c.old 2009-11-24 10:05:09.000000000 +0000
+++ sv.c 2009-12-04 14:17:55.000000000 +0000
@@ -9161,6 +9161,22 @@
sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, maybe_tainted);
}
+
+/*
+ * Warn of missing argument to sprintf, and then return a defined value
+ * to avoid inappropriate "use of uninit" warnings [perl #71000].
+ */
+#define WARN_MISSING WARN_UNINITIALIZED /* Not sure we want a new category */
+STATIC SV*
+S_vcatpvfn_missing_argument(pTHX_) {
+ if (ckWARN(WARN_MISSING)) {
+ Perl_warner(aTHX_ packWARN(WARN_MISSING), "Missing argument in %s",
+ PL_op ? OP_DESC(PL_op) : "sv_vcatpvfn()");
+ }
+ return &PL_sv_no;
+}
+
+
STATIC I32
S_expect_number(pTHX_ char **const pattern)
{
@@ -9526,9 +9542,10 @@
vecsv = va_arg(*args, SV*);
else if (evix) {
vecsv = (evix > 0 && evix <= svmax)
- ? svargs[evix-1] : &PL_sv_undef;
+ ? svargs[evix-1] : S_vcatpvfn_missing_argument();
} else {
- vecsv = svix < svmax ? svargs[svix++] : &PL_sv_undef;
+ vecsv = svix < svmax
+ ? svargs[svix++] : S_vcatpvfn_missing_argument();
}
dotstr = SvPV_const(vecsv, dotstrlen);
/* Keep the DO_UTF8 test *after* the SvPV call, else things go
@@ -9675,10 +9692,11 @@
if (!vectorize && !args) {
if (efix) {
const I32 i = efix-1;
- argsv = (i >= 0 && i < svmax) ? svargs[i] : &PL_sv_undef;
+ argsv = (i >= 0 && i < svmax)
+ ? svargs[i] : S_vcatpvfn_missing_argument();
} else {
argsv = (svix >= 0 && svix < svmax)
- ? svargs[svix++] : &PL_sv_undef;
+ ? svargs[svix++] : S_vcatpvfn_missing_argument();
}
}
--- pod/perldiag.pod.old 2009-11-21 19:02:10.000000000 +0000
+++ pod/perldiag.pod 2009-12-04 14:20:46.000000000 +0000
@@ -2425,6 +2425,11 @@
(W syntax) An underscore (underbar) in a numeric constant did not
separate two digits.
+=item Missing argument in %s
+
+(W uninitialized) A printf-type format required more arguments than were
+supplied.
+
=item Missing argument to -%c
(F) The argument to the indicated command line switch must follow
--- t/op/sprintf.t.old 2009-11-19 16:51:40.000000000 +0000
+++ t/op/sprintf.t 2009-12-04 14:16:48.000000000 +0000
@@ -60,6 +60,8 @@
$w = ' INVALID';
} elsif ($_[0] =~ /^Use of uninitialized value/) {
$w = ' UNINIT';
+ } elsif ($_[0] =~ /^Missing argument/) {
+ $w = ' MISSING';
} else {
warn @_;
}
@@ -618,7 +620,7 @@
>%3$d %d %d< >[12, 34, 56]< >56 12 34<
>%2$*3$d %d< >[12, 34, 3]< > 34 12<
>%*3$2$d %d< >[12, 34, 3]< >%*3$2$d 12 INVALID<
->%2$d< >12< >0 UNINIT<
+>%2$d< >12< >0 MISSING<
>%0$d< >12< >%0$d INVALID<
>%1$$d< >12< >%1$$d INVALID<
>%1$1$d< >12< >%1$1$d INVALID<
@@ -685,4 +687,4 @@
>%#o< >0< >0<
>%#x< >0< >0<
>%2147483647$v2d< >''< ><
->%*2147483647$v2d< >''< > UNINIT<
+>%*2147483647$v2d< >''< > MISSING<
--- t/op/sprintf2.t.old 2009-11-19 16:51:40.000000000 +0000
+++ t/op/sprintf2.t 2009-12-04 14:48:38.000000000 +0000
@@ -41,9 +41,9 @@
}
# Used to mangle PL_sv_undef
-fresh_perl_is(
+fresh_perl_like(
'print sprintf "xxx%n\n"; print undef',
- 'Modification of a read-only value attempted at - line 1.',
+ 'Modification of a read-only value attempted at - line 1\.',
{ switches => [ '-w' ] },
q(%n should not be able to modify read-only constants),
);
@@ -60,7 +60,7 @@
{
my ($warn, $bad) = (0,0);
local $SIG{__WARN__} = sub {
- if ($_[0] =~ /uninitialized/) {
+ if ($_[0] =~ /missing argument/i) {
$warn++
}
else {
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