Add undefined-subs option to Lint.pm.

p4raw-id: //depot/perlext/Compiler@65

diff --git a/B/Lint.pm b/B/Lint.pm
index 3b4ea7e..d9659f9 100644 (file)
--- a/B/Lint.pm
+++ b/B/Lint.pm
@@ -67,6 +67,15 @@ lives in a non-current package but begins with an underscore ("_").
 Warnings aren't issued for the special case of the single character
 name "_" by itself (e.g. $_ and @_).
 
+=item B<undefined-subs>
+
+This option warns whenever an undefined subroutine is invoked.
+This option will only catch explicitly invoked subroutines such
+as C<foo()> and not indirect invocations such as C<&$subref()>
+or C<$obj-E<gt>meth()>. Note that some programs or modules delay
+definition of subs until runtime by means of the AUTOLOAD
+mechanism.
+
 =item B<all>
 
 Turn all warnings on.
@@ -129,7 +138,7 @@ my %valid_check;
 BEGIN {
     map($valid_check{$_}++,
        qw(context implicit_read implicit_write dollar_underscore
-          private_names));
+          private_names undefined_subs));
 }
 
 # Debugging options
@@ -239,6 +248,17 @@ sub B::GVOP::lint {
            warning('Illegal reference to private name %s', $gv->NAME);
        }
     }
+    if ($check{undefined_subs}) {
+       if ($op->ppaddr eq "pp_gv" && $op->next->ppaddr eq "pp_entersub") {
+           my $gv = $op->gv;
+           my $subname = $gv->STASH->NAME . "::" . $gv->NAME;
+           no strict 'refs';
+           if (!defined(&$subname)) {
+               $subname =~ s/^main:://;
+               warning('Undefined subroutine %s called', $subname);
+           }
+       }
+    }
 }
 
 sub B::GV::lintcv {