bug: rename() breaks open file handles — reads return EOF, writes warn

[toddr-bot]

Summary

After rename('/old', '/new'), any filehandle opened on /old loses access to the file data. Reads return EOF (0 bytes), writes produce uninitialized-value warnings, and eof() triggers warnings.

Reproduction

use Test::MockFile qw(nostrict);

my $old = Test::MockFile->file('/tmp/old.txt', 'Hello World');
my $new = Test::MockFile->file('/tmp/new.txt', '');

open my $fh, '<', '/tmp/old.txt' or die;
read($fh, my $buf, 5);  # "Hello" — works fine

rename('/tmp/old.txt', '/tmp/new.txt');

read($fh, $buf, 6);     # Should be " World", gets EOF (0)
# Warning: Use of uninitialized value $contents_len in numeric ge (>=)

Expected behavior

Open file descriptors follow the inode (Unix semantics). After rename, the handle should continue reading/writing the data at its new location.

Root cause

The tied FileHandle object stores a weak data ref to $files_being_mocked{'/tmp/old.txt'}. When __rename transfers contents to the new mock, it sets $mock_old->{'contents'} = undef — but the handle's data still points to the old mock.

Fix

PR #346

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🤖 Created by Kōan from autonomous session