Make behavior of $Carp::MaxArgNums match docs

$Carp::MaxArgNums is supposed to be the number of arguments to display.
For a long time, Carp has instead shown $Carp::MaxArgNums + 1 arguments.
Correct the behavior by making it match the documentation.  Also update
tests to make what's being tested more obvious.

4 files changed, 24 insertions, 10 deletions

diff --git a/AUTHORS b/AUTHORS
index 3ef849917b..b5ef9120f9 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -63,6 +63,7 @@ Alex Solovey			<a.solovey@gmail.com>
 Alex Vandiver			<alexmv@mit.edu>
 Alex Waugh			<alex@alexwaugh.com>
 Alexander Bluhm			<alexander_bluhm@genua.de>
+Alexander D'Archangel   <darksuji@gmail.com>
 Alexander Gernler		<alexander_gernler@genua.de>
 Alexander Gough			<alex-p5p@earth.li>
 Alexander Klimov		<ask@wisdom.weizmann.ac.il>
diff --git a/dist/Carp/lib/Carp.pm b/dist/Carp/lib/Carp.pm
index 5b191ebfe2..61192b8579 100644
--- a/dist/Carp/lib/Carp.pm
+++ b/dist/Carp/lib/Carp.pm
@@ -87,7 +87,7 @@ BEGIN {
     }
 }
 
-our $VERSION = '1.36';
+our $VERSION = '1.37';
 
 our $MaxEvalLen = 0;
 our $Verbose    = 0;
@@ -229,7 +229,7 @@ sub caller_info {
             my $overflow;
             if ( $MaxArgNums and @args > $MaxArgNums )
             {    # More than we want to show?
-                $#args = $MaxArgNums;
+                $#args = $MaxArgNums - 1;
                 $overflow = 1;
             }
 
@@ -783,7 +783,8 @@ Defaults to C<64>.
 =head2 $Carp::MaxArgNums
 
 This variable determines how many arguments to each function to show.
-Use a value of C<0> to show all arguments to a function call.
+Use a false value to show all arguments to a function call.  To suppress all
+arguments, use C<-1> or C<'0 but true'>.
 
 Defaults to C<8>.
 
diff --git a/dist/Carp/lib/Carp/Heavy.pm b/dist/Carp/lib/Carp/Heavy.pm
index a602297ed0..ed446c506c 100644
--- a/dist/Carp/lib/Carp/Heavy.pm
+++ b/dist/Carp/lib/Carp/Heavy.pm
@@ -2,7 +2,7 @@ package Carp::Heavy;
 
 use Carp ();
 
-our $VERSION = '1.36';
+our $VERSION = '1.37';
 
 # Carp::Heavy was merged into Carp in version 1.12.  Any mismatched versions
 # after this point are not significant and can be ignored.
diff --git a/dist/Carp/t/Carp.t b/dist/Carp/t/Carp.t
index 3d707a13b1..c86f5ffb1e 100644
--- a/dist/Carp/t/Carp.t
+++ b/dist/Carp/t/Carp.t
@@ -3,7 +3,7 @@ no warnings "once";
 use Config;
 
 use IPC::Open3 1.0103 qw(open3);
-use Test::More tests => 60;
+use Test::More tests => 65;
 
 sub runperl {
     my(%args) = @_;
@@ -237,16 +237,28 @@ sub w { cluck @_ }
 
 # $Carp::MaxArgNums
 {
-    my $i    = 0;
     my $aref = [
-        qr/1234 at \S*(?i:carp.t) line \d+\.\n\s*main::w\(1, 2, 3, 4\) called at \S*(?i:carp.t) line \d+/,
-        qr/1234 at \S*(?i:carp.t) line \d+\.\n\s*main::w\(1, 2, \.\.\.\) called at \S*(?i:carp.t) line \d+/,
+        [ -1            => '(...)' ],
+        [ 0             => '(1, 2, 3, 4)' ],
+        [ '0 but true'  => '(...)' ],
+        [ 1             => '(1, ...)' ],
+        [ 3             => '(1, 2, 3, ...)' ],
+        [ 4             => '(1, 2, 3, 4)' ],
+        [ 5             => '(1, 2, 3, 4)' ],
     ];
 
     for (@$aref) {
-        local $Carp::MaxArgNums = $i++;
+        my ($arg_count, $expected_signature) = @$_;
+
+        my $expected = join('',
+            '1234 at \S*(?i:carp.t) line \d+\.\n\s*main::w',
+            quotemeta $expected_signature,
+            ' called at \S*(?i:carp.t) line \d+'
+        );
+
+        local $Carp::MaxArgNums = $arg_count;
         local $SIG{__WARN__} = sub {
-            like "@_", $_, 'MaxArgNums';
+            like "@_", qr/$expected/, "MaxArgNums=$arg_count";
         };
 
         package Z;