diff fixed for emptied/filled subhashes

README.md

@@ -8,7 +8,7 @@ Struct::Diff - Recursive diff for nested perl structures
 
 # VERSION
 
-Version 0.91
+Version 0.92
 
 # SYNOPSIS
 

lib/Struct/Diff.pm

@@ -31,11 +31,11 @@ Struct::Diff - Recursive diff for nested perl structures
 
 =head1 VERSION
 
-Version 0.91
+Version 0.92
 
 =cut
 
-our $VERSION = '0.91';
+our $VERSION = '0.92';
 
 =head1 SYNOPSIS
 
@@ -171,12 +171,13 @@ sub diff($$;@) {
         my @keys = keys %{{ %{$a}, %{$b} }}; # uniq keys for both hashes
         return $opts{noU} ? {} : { U => {} } unless (@keys);
 
-        my ($alt, $sd);
+        my ($alt, $sd, $same);
         for my $key (@keys) {
             if (exists $a->{$key} and exists $b->{$key}) {
                 if (freeze(\$a->{$key}) eq freeze(\$b->{$key})) {
                     $d->{U}->{$key} = $alt->{D}->{$key}->{U} = $a->{$key}
                         unless ($opts{noU});
+                    $same++;
                 } else {
                     $sd = diff($a->{$key}, $b->{$key}, %opts);
                     if (exists $sd->{D}) {
@@ -197,8 +198,7 @@ sub diff($$;@) {
             }
         }
 
-        $d = $alt # return 'D' version of diff
-            if (keys %{$d} > 1 or ($sd) = values %{$d} and keys %{$sd} != @keys);
+        return $alt if ($alt and ($sd or $same and $same != @keys)); # 'D' version of diff
     } elsif (ref $a eq 'Regexp' and $a != $b) {
         if ($a eq $b) {
             $d->{U} = $a unless ($opts{noU});

t/diff-structures.t

@@ -4,7 +4,7 @@ use strict;
 use warnings;
 use Storable qw(freeze);
 use Struct::Diff qw(diff);
-use Test::More tests => 39;
+use Test::More tests => 42;
 
 local $Storable::canonical = 1; # to have equal snapshots for equal by data hashes
 
@@ -137,6 +137,37 @@ is_deeply($d, {R => {a => 'va'}}, "{a => 'va'} vs {}");
 $d = diff({ 'a' => 'va' }, {}, 'noR' => 1);
 is_deeply($d, {}, "{a => 'va'} vs {}, noR => 1");
 
+$d = diff(
+    {one => {two => 2}},
+    {one => {}},
+);
+is_deeply(
+    $d,
+    {D => {one => {R => {two => 2}}}},
+    "Subhash emptied"
+);
+
+$d = diff(
+    {one => {}},
+    {one => {two => 2}},
+);
+is_deeply(
+    $d,
+    {D => {one => {A => {two => 2}}}},
+    "Subhash filled"
+);
+
+$d = diff(
+    {one => {}},
+    {one => {two => 2}},
+    noA => 1
+);
+is_deeply(
+    $d,
+    {},
+    "Subhash filled, but noA used"
+);
+
 $d = diff(
     {a =>{aa => {aaa => 'aaav'}}},
     {a =>{aa => {aaa => 'aaan'}}},
@@ -169,10 +200,10 @@ is_deeply(
 );
 
 $d = diff({ 'a' => 'va' }, { 'a' => 'vb' }, 'noO' => 1);
-is_deeply($d, {N => {a => 'vb'}}, "{a => 'va'} vs {a => 'vb'}, noO => 1");
+is_deeply($d, {D => {a => {N=> 'vb'}}}, "{a => 'va'} vs {a => 'vb'}, noO => 1");
 
 $d = diff({ 'a' => 'va' }, { 'a' => 'vb' }, 'noN' => 1);
-is_deeply($d, {O => {a => 'va'}}, "{a => 'va'} vs {a => 'vb'}, noN => 1");
+is_deeply($d, {D => {a => {O=>'va'}}}, "{a => 'va'} vs {a => 'vb'}, noN => 1");
 
 $a = { 'a' => 'a1', 'b' => { 'ba' => 'ba1', 'bb' => 'bb1' }, 'c' => 'c1' };
 $b = { 'a' => 'a1', 'b' => { 'ba' => 'ba2', 'bb' => 'bb1' }, 'd' => 'd1' };