Reset isa on stash manipulation

This only applies to glob-to-glob assignments and deletions of stash
elements. Other types of stash manipulation are dealt with by subse-
quent patches.

It adds mro_package_moved, a private function that iterates through
subpackages, calling mro_isa_changed_in on each.

This is related to [perl #75176], but is not the same bug. It simply
got in the way of fixing [perl #75176].

1 files changed, 76 insertions, 1 deletions

diff --git a/t/mro/package_aliases.t b/t/mro/package_aliases.t
index b8d03160ae..611ebf51f7 100644
--- a/t/mro/package_aliases.t
+++ b/t/mro/package_aliases.t
@@ -5,11 +5,12 @@ BEGIN {
         chdir 't' if -d 't';
         @INC = '../lib';
     }
+    require q(./test.pl);
 }
 
 use strict;
 use warnings;
-require q(./test.pl); plan(tests => 4);
+require q(./test.pl); plan(tests => 10);
 
 {
     package New;
@@ -31,3 +32,77 @@ ok (New->isa (Old::), 'New inherits from Old');
 
 isa_ok (bless ({}, Old::), New::, 'Old object');
 isa_ok (bless ({}, New::), Old::, 'New object');
+
+
+no warnings; # temporary, until bug #77358 is fixed
+
+# Test that replacing a package by assigning to an existing glob
+# invalidates the isa caches
+{
+ @Subclass::ISA = "Left";
+ @Left::ISA = "TopLeft";
+
+ sub TopLeft::speak { "Woof!" }
+ sub TopRight::speak { "Bow-wow!" }
+
+ my $thing = bless [], "Subclass";
+
+ # mro_package_moved needs to know to skip non-globs
+ $Right::{"gleck::"} = 3;
+
+ @Right::ISA = 'TopRight';
+ my $life_raft = $::{'Left::'};
+ *Left:: = $::{'Right::'};
+
+ is $thing->speak, 'Bow-wow!',
+  'rearranging packages by assigning to a stash elem updates isa caches';
+
+ undef $life_raft;
+ is $thing->speak, 'Bow-wow!',
+  'isa caches are up to date after the replaced stash is freed';
+}
+
+# Similar test, but with nested packages
+{
+ @Subclass::ISA = "Left::Side";
+ @Left::Side::ISA = "TopLeft";
+
+ sub TopLeft::speak { "Woof!" }
+ sub TopRight::speak { "Bow-wow!" }
+
+ my $thing = bless [], "Subclass";
+
+ @Right::Side::ISA = 'TopRight';
+ my $life_raft = $::{'Left::'};
+ *Left:: = $::{'Right::'};
+
+ is $thing->speak, 'Bow-wow!',
+  'moving nested packages by assigning to a stash elem updates isa caches';
+
+ undef $life_raft;
+ is $thing->speak, 'Bow-wow!',
+  'isa caches are up to date after the replaced nested stash is freed';
+}
+
+# Test that deleting stash elements containing
+# subpackages also invalidates the isa cache.
+# Maybe this does not belong in package_aliases.t, but it is closely
+# related to the tests immediately preceding.
+{
+ @Pet::ISA = ("Cur", "Hound");
+ @Cur::ISA = "Hylactete";
+
+ sub Hylactete::speak { "Arff!" }
+ sub Hound::speak { "Woof!" }
+
+ my $pet = bless [], "Pet";
+
+ my $life_raft = delete $::{'Cur::'};
+
+ is $pet->speak, 'Woof!',
+  'deleting a stash from its parent stash invalidates the isa caches';
+
+ undef $life_raft;
+ is $pet->speak, 'Woof!',
+  'the deleted stash is gone completely when freed';
+}