feat: add autodie compatibility (#44)

[Koan-Bot]

Summary

Fixes #44. Makes Test::MockFile compatible with autodie — both modules can now coexist regardless of load order.

Root Cause

autodie installs per-package wrappers (e.g., main::open) that call CORE::open directly, bypassing CORE::GLOBAL::open where Test::MockFile installs its overrides. Perl's builtin resolution order is:

1. Package namespace (main::open) — autodie wins here
2. CORE::GLOBAL::open — T::MF installs here, but never reached
3. CORE::open — the C-level builtin

Solution

• Per-package overrides: import() now installs goto-transparent wrappers into the caller's namespace, ensuring T::MF's overrides take precedence over autodie's
• CHECK block: Re-installs overrides after all compilation, handling the case where use autodie appears after use Test::MockFile
• _autodie_croak(): When autodie is lexically active (checked via %^H hints) and a mocked operation fails, throws an autodie::exception (or formatted die fallback)
• goto optimization: Disabled when autodie/Fatal is loaded, so return values can be checked for die-on-failure

Changes

• _install_package_overrides(): installs goto wrappers for all 14 overridden builtins
• _autodie_croak(): detects autodie scope via caller hints, throws compatible exception
• __open / __sysopen: modified fallback paths to check results when autodie is active
• POD: autodie compatibility documented in CAVEATS section

Test plan

• t/autodie_compat.t — autodie loaded before T::MF: read, write, append, die-on-failure, exception type
• t/autodie_compat_reverse.t — T::MF loaded before autodie: read, write, die-on-failure (tests CHECK block)
• Existing test suite passes (no regressions from per-package override installation)
• Both use autodie; use Test::MockFile and use Test::MockFile; use autodie work correctly

Example (from issue #44)

# Previously: "Can't open '/log' for reading: 'No such file or directory'"
# Now: works correctly
use autodie;
use Test::MockFile qw(nostrict);
my $mock = Test::MockFile->file('/log', "one\ntwo\n");
open(my $fh, '<', '/log');
say <$fh>;  # prints "one\n"

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🤖 Generated with Claude Code

[Koan-Bot]

CI Fix: $@ clobbering in autodie exception test

Root cause: In t/autodie_compat.t, the test at line 102 used eval { require autodie::exception; 1 } to check if the exception class is loadable. A successful eval {} always clears $@ to '' — this destroyed the exception captured from the first eval block.

Fix: Save $@ to $err immediately after the first eval, before the second eval clobbers it.

+    my $err = $@;    # Save before next eval clobbers it
     if ( eval { require autodie::exception; 1 } ) {
-        isa_ok( $@, 'autodie::exception', ... );
+        isa_ok( $err, 'autodie::exception', ... );

• Root cause identified
• Fix committed and pushed (5b055b4)
• Waiting for CI to confirm green

---

🤖 Kōan

[atoomic]

view issue from smokers, for example on Perl 5.10

# Perl 5.010001, /usr/local/bin/perl
t/00-load.t ......................... ok

    #   Failed test 'autodie dies when opening non-existent mocked file'
    #   at t/autodie_compat.t line 90.
    # Looks like you failed 1 test of 1.

#   Failed test 'autodie dies on non-existent mocked file'
#   at t/autodie_compat.t line 92.

    #   Failed test ''exception is autodie::exception object' isa 'autodie::exception''
    #   at t/autodie_compat.t line 103.
    #     'exception is autodie::exception object' isn't a 'autodie::exception'
    # Looks like you failed 1 test of 1.

#   Failed test 'autodie exception is autodie::exception when possible'
#   at t/autodie_compat.t line 109.

    #   Failed test 'autodie dies on +< open of non-existent mocked file'
    #   at t/autodie_compat.t line 120.
    # Looks like you failed 1 test of 1.

#   Failed test '+< mode on non-existent mocked file dies with autodie'
#   at t/autodie_compat.t line 121.
# Looks like you failed 3 tests of 7.
t/autodie_compat.t .................. 
Dubious, test returned 3 (wstat 768, 0x300)
Failed 3/7 subtests 
t/autodie_compat_reverse.t .......... ok
t/chmod-chown-passthrough.t ......... ok
t/chmod-filetemp.t .................. skipped: Skip for now < 5.28
t/chmod.t ........................... ok
t/chown-chmod-nostrict.t ............ ok
t/chown.t ........................... ok
t/detect-common-mistakes.t .......... ok
t/dir_interface.t ................... ok
t/file_access_hooks.t ............... ok
t/file_from_disk.t .................. ok
t/fileno.t .......................... ok
t/flock.t ........................... ok
t/globbing.t ........................ ok
t/goto_is_available.t ............... ok
t/handle-corruption.t ............... ok

# Failed test 'Unexpected warning: Too late to run CHECK block at (eval 33) line 1.'
# [No trace info available]
# Seeded srand with seed '20260225' from local date.
t/import.t .......................... 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/8 subtests 
t/manifest.t ........................ skipped: Test::CheckManifest is broken - https://github.com/reneeb/Test-CheckManifest/issues/20
t/mkdir.t ........................... ok
t/mock_stat.t ....................... ok
t/new_dir_interface.t ............... ok
t/open-noclose.t .................... ok
t/open.t ............................ ok
t/open_strict.t ..................... ok
t/opendir.t ......................... ok
t/path.t ............................ ok
t/plugin-filetemp.t ................. skipped: Skip for now < 5.28

# Failed test 'Unexpected warning: Too late to run CHECK block at (eval 33) line 1.'
# [No trace info available]
# Seeded srand with seed '20260225' from local date.
t/plugin.t .......................... 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/7 subtests 
t/pod-coverage.t .................... skipped: Author tests not required for installation
t/pod.t ............................. skipped: Author tests not required for installation
t/readline.t ........................ ok
t/readlink.t ........................ ok
t/rmdir.t ........................... ok
t/runtime-bareword-filehandles.t .... ok
t/seek.t ............................ ok
t/stat-x.t .......................... ok
t/strict-rules.t .................... ok
t/strict-rules_file-temp-example.t .. ok
t/strict-rules_scalar.t ............. ok
t/symlink.t ......................... ok
t/sysopen.t ......................... ok
t/sysopen_strict.t .................. skipped: Needs FileTemp plugin
t/Test-MockFile_file.t .............. ok
t/touch.t ........................... ok
t/unlink.t .......................... ok
t/utime.t ........................... ok
t/utime_strict.t .................... ok
t/writeline.t ....................... ok

Test Summary Report
-------------------
t/autodie_compat.t                (Wstat: 768 (exited 3) Tests: 7 Failed: 3)
  Failed tests:  4-6
  Non-zero exit status: 3
t/import.t                        (Wstat: 256 (exited 1) Tests: 8 Failed: 1)
  Failed test:  1
  Non-zero exit status: 1
t/plugin.t                        (Wstat: 256 (exited 1) Tests: 7 Failed: 1)
  Failed test:  1
  Non-zero exit status: 1
Files=49, Tests=525,  4 wallclock secs ( 0.12 usr  0.06 sys +  3.60 cusr  1.23 csys =  5.01 CPU)
Result: FAIL
Failed 3/49 test programs. 5/525 subtests failed.
make: *** [Makefile:882: test_dynamic] Error 255
Error: Process completed with exit code 2.