Perl produces silly and repetitive warnings for nonexistent packages in @ISA #11259
Comments
From @demerphqCreated by @demerphqThis is a bug report for perl from demerphq@gmail.com, ----------------------------------------------------------------- $ ./perl -Ilib -wle'@Y::ISA=qw( Z ); @X::ISA=qw( Y ); print On one older perl (5.8.9) this throws a different set of warnings, $ perl -wle'@Y::ISA=qw( Z ); @X::ISA=qw( Y ); print Can't locate package Z for @Y::ISA. On blead we get the warnings, but at least the correct result. I don't think this should warn at all. Perl Info |
From @demerphq0001-Improve-warnings-for-undefined-class-in-ISA.patchFrom f1e6479007985219e728573b9a294934f683b47b Mon Sep 17 00:00:00 2001
From: Yves Orton <demerphq@gmail.com>
Date: Sun, 17 Apr 2011 16:46:29 +0200
Subject: [PATCH] Improve warnings for undefined class in @ISA
And silence some silly examples.
---
gv.c | 19 +++++++++++-
pod/perldiag.pod | 12 ++++++++
t/lib/warnings/gv | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 109 insertions(+), 3 deletions(-)
diff --git a/gv.c b/gv.c
index d22a439..2b29531 100644
--- a/gv.c
+++ b/gv.c
@@ -486,8 +486,23 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
cstash = gv_stashsv(linear_sv, 0);
if (!cstash) {
- Perl_ck_warner(aTHX_ packWARN(WARN_SYNTAX), "Can't locate package %"SVf" for @%s::ISA",
- SVfARG(linear_sv), hvname);
+ if ( Perl_ckwarn(aTHX_ packWARN(WARN_SYNTAX)) &&
+ !( /* these are loaded from Perl_Gv_AMupdate() one way or another */
+ ( len && name[0] == '(' ) /* overload.pm related, in particular "()" */
+ || ( len==7 && strEQ( name, "DESTROY") )
+ || ( len==8 && strEQ( name, "AUTOLOAD") )
+ )
+ ) {
+ Perl_ck_warner(aTHX_ packWARN(WARN_SYNTAX),
+ "While trying to resolve method call %.*s->%.*s()"
+ " can not locate package \"%"SVf"\" yet it is mentioned in @%.*s::ISA"
+ " (perhaps you forgot to load \"%"SVf"\"?)",
+ packlen, hvname,
+ len, name,
+ SVfARG(linear_sv),
+ packlen, hvname,
+ SVfARG(linear_sv));
+ }
continue;
}
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 88c55a8..3b73f34 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -5487,6 +5487,18 @@ C<TEMPLATE> always matches the same amount of packed bytes that can be
determined from the template alone. This is not possible if it contains any
of the codes @, /, U, u, w or a *-length. Redesign the template.
+=item While trying to resolve method call %s->%s() can not locate package "%s" yet it is mentioned in @%s::ISA (perhaps you forgot to load "%s"?)
+
+(W) It is possible that the @ISA contains a misspelled or never loaded
+package name, which can result in perl choosing an unexpected parent
+classes method to resolve the method call. If this is deliberate you
+can do something like
+
+ @Missing::Package::ISA = ();
+
+to silence the warnings, otherwise you should correct the package name, or
+ensure that the package is loaded prior to the method call.
+
=item write() on closed filehandle %s
(W closed) The filehandle you're writing to got itself closed sometime
diff --git a/t/lib/warnings/gv b/t/lib/warnings/gv
index 42565f2..ea2f932 100644
--- a/t/lib/warnings/gv
+++ b/t/lib/warnings/gv
@@ -25,7 +25,6 @@ __END__
use warnings 'syntax' ;
@ISA = qw(Fred); joe()
EXPECT
-Can't locate package Fred for @main::ISA at - line 3.
Undefined subroutine &main::joe called at - line 3.
########
# gv.c
@@ -35,6 +34,86 @@ EXPECT
Undefined subroutine &main::joe called at - line 3.
########
# gv.c
+use warnings 'syntax' ;
+@ISA = qw(Fred); __PACKAGE__->joe()
+EXPECT
+While trying to resolve method call main->joe() can not locate package "Fred" yet it is mentioned in @main::ISA (perhaps you forgot to load "Fred"?) at - line 3.
+Can't locate object method "joe" via package "main" at - line 3.
+########
+# gv.c
+no warnings 'syntax' ;
+@ISA = qw(Fred); __PACKAGE__->joe()
+EXPECT
+Can't locate object method "joe" via package "main" at - line 3.
+########
+# gv.c
+use warnings 'syntax' ;
+{
+ package AA; # this is a deliberate error
+# package A; # should be this
+ sub foo {
+ print STDERR "I'm in A's foo\n";
+ }
+}
+{
+ package B;
+ sub foo {
+ print STDERR "I'm in B's foo\n";
+ }
+}
+@C::ISA = qw(A B);
+$a = bless [], 'C';
+$a->foo();
+__END__
+EXPECT
+While trying to resolve method call C->foo() can not locate package "A" yet it is mentioned in @C::ISA (perhaps you forgot to load "A"?) at - line 18.
+I'm in B's foo
+########
+# gv.c
+no warnings 'syntax' ;
+{
+ package AA; # this is a deliberate error
+# package A; # should be this
+ sub foo {
+ print STDERR "I'm in A's foo\n";
+ }
+}
+{
+ package B;
+ sub foo {
+ print STDERR "I'm in B's foo\n";
+ }
+}
+@C::ISA = qw(A B);
+$a = bless [], 'C';
+$a->foo();
+__END__
+EXPECT
+I'm in B's foo
+########
+# gv.c
+use warnings 'syntax' ;
+{
+# package AA; # this would be an error
+ package A; # the right thing
+ sub foo {
+ print STDERR "I'm in A's foo\n";
+ }
+}
+{
+ package B;
+ sub foo {
+ print STDERR "I'm in B's foo\n";
+ }
+}
+@C::ISA = qw(A B);
+$a = bless [], 'C';
+$a->foo();
+__END__
+EXPECT
+I'm in A's foo
+########
+# gv.c
sub Other::AUTOLOAD { 1 } sub Other::fred {}
@ISA = qw(Other) ;
use warnings 'deprecated' ;
--
1.7.0.4
|
From @jkeenanOn Sun Apr 17 08:24:41 2011, demerphq wrote:
What should be the desired behavior? Thank you very much. |
|
The RT System itself - Status changed from 'new' to 'open' |
From @demerphqOn 26 September 2012 05:13, James E Keenan via RT
Thanks for reviving this, I think it either should not warn, or it As I recall I have a fix for this somewhere. Yves -- |
From @jkeenanOn Wed Sep 26 05:54:22 2012, demerphq wrote:
Have you had a chance to track down that fix? :-) |
From @demerphqOn 15 January 2013 03:55, James E Keenan via RT
Yeah, but some other patches conflicted and it got lost after a -- |
And silence some silly examples. From RT88754 Adapted to the current Perl by Max Maischein This patch deviates from the original author and makes the warning of category S (always) instead of the original warning category W (only with warnings). Please consider whether this should be changed. Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein This patch deviates from the original author and makes the warning of category S (always) instead of the original warning category W (only with warnings). Please consider whether this should be changed. Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein This patch deviates from the original author and makes the warning of category S (always) instead of the original warning category W (only with warnings). Please consider whether this should be changed. Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein Created from #11259
From RT88754 Adapted to the current Perl by Max Maischein Created from #11259
Migrated from rt.perl.org#88754 (status was 'open')
Searchable as RT88754$
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