Index::$accessMethod uninitialized property

[mirko-pagliai]

Description

I updated CakePHP to 5.4.0.
The Migrations plugin is the latest version.

Now, using BakeMigrationDiffCommand I get this:

$ bin/cake bake migration_diff --generate-only -v SimpleTest
2026-07-21 21:04:02 error: [Error] Typed property Cake\Database\Schema\Index::$accessMethod must not be accessed before initialization in /home/mirko/PhpstormProjects/climat/vendor/cakephp/cakephp/src/Database/Schema/Index.php on line 312
Stack Trace:                                                                                                                                                                                                                                                                                          
- CORE/src/Database/Schema/TableSchema.php:638                                                                                                                                                                                                                                                        
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:470                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:223                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:205                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php:185                                                                                                                                                                                                                       
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:143                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php:143                                                                                                                                                                                                                       
- CORE/src/Console/BaseCommand.php:261                                                                                                                                                                                                                                                                
- CORE/src/Console/CommandRunner.php:451                                                                                                                                                                                                                                                              
- CORE/src/Console/CommandRunner.php:205                                                                                                                                                                                                                                                              
- ROOT/bin/cake.php:12                                                                                                                                                                                                                                                                                
- [main]:                                                                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                                                      
[Error] Typed property Cake\Database\Schema\Index::$accessMethod must not be accessed before initialization in /home/mirko/PhpstormProjects/climat/vendor/cakephp/cakephp/src/Database/Schema/Index.php on line 312

Stack Trace:

Cake\Database\Schema\Index->toArray() - CORE/src/Database/Schema/TableSchema.php, line 638
Cake\Database\Schema\TableSchema->getIndex() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 470
Migrations\Command\BakeMigrationDiffCommand->getIndexes() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 223
Migrations\Command\BakeMigrationDiffCommand->calculateDiff() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 205
Migrations\Command\BakeMigrationDiffCommand->templateData() - ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php, line 185
Migrations\Command\BakeSimpleMigrationCommand->bake() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 143
Migrations\Command\BakeMigrationDiffCommand->bake() - ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php, line 143
Migrations\Command\BakeSimpleMigrationCommand->execute() - CORE/src/Console/BaseCommand.php, line 261
Cake\Console\BaseCommand->run() - CORE/src/Console/CommandRunner.php, line 451
Cake\Console\CommandRunner->runCommand() - CORE/src/Console/CommandRunner.php, line 205
Cake\Console\CommandRunner->run() - ROOT/bin/cake.php, line 12
[main] - [main], line 0

It seems to me that the problem is here:
https://github.com/cakephp/migrations/blob/5.x/src/Command/BakeMigrationDiffCommand.php#L470

$index !== $this->dumpSchema[$table]->getIndex($indexName)

Index is retrieved and, doing an array comparison, its toArray() method is called.

https://github.com/cakephp/cakephp/compare/5.3.7...5.4.0?diff=unified&w#diff-7168039bb639937121b38cff5babc9801bd771c697b0dda0bbb0f8dfe88c91a2R300

I'll point out that I'm on MariaDB, just in case. I think the problem is with Cake and not Migrations, but I could be wrong.

CakePHP Version

5.4

PHP Version

No response

[dereuromark]

These kind of issues usally are stale cache or session.
Make sure you ran bin/cake cache clear_all etc after the upgrade.

[runzinger]

I had a similar problem after updating to 5.4.0 when just calling a URL that was working fine under 5.3.7 showed me this all of a sudden:

2026-07-20 09:34:23 error: [Error] Typed property Cake\Database\Schema\Column::
$geometryType must not be accessed before initialization in
/[redacted]/[redacted]/[redacted]/vendor/cakephp/cakephp/src/Database/Schema/Column.php on line 530
Stack Trace:
- CORE/src/Database/Schema/Column.php:661
- CORE/src/Database/Schema/TableSchema.php:441
- CORE/src/ORM/Table.php:621
- CORE/src/Datasource/Paging/NumericPaginator.php:801
- CORE/src/Datasource/Paging/NumericPaginator.php:729
- CORE/src/Datasource/Paging/NumericPaginator.php:361
- CORE/src/Datasource/Paging/NumericPaginator.php:247
- CORE/src/Controller/Controller.php:913
- APP/Controller/NewsController.php:93
- CORE/src/Controller/Controller.php:521
- CORE/src/Controller/ControllerFactory.php:168
- CORE/src/Controller/ControllerFactory.php:143
- CORE/src/Http/BaseApplication.php:384
- CORE/src/Http/Runner.php:86
- ROOT/vendor/muffin/footprint/src/Middleware/FootprintMiddleware.php:50
- CORE/src/Http/Runner.php:82
- ROOT/vendor/cakephp/authorization/src/Middleware/AuthorizationMiddleware.php:132
- CORE/src/Http/Runner.php:82
- ROOT/vendor/cakephp/authentication/src/Middleware/AuthenticationMiddleware.php:103
- CORE/src/Http/Runner.php:82
- CORE/src/Http/Middleware/BodyParserMiddleware.php:157
- CORE/src/Http/Runner.php:82
- CORE/src/Http/Runner.php:86
- CORE/src/Http/Middleware/CsrfProtectionMiddleware.php:159
- CORE/src/Http/Runner.php:82
- CORE/src/Http/Runner.php:60
- CORE/src/Routing/Middleware/RoutingMiddleware.php:127
- CORE/src/Http/Runner.php:82
- CORE/src/Routing/Middleware/AssetMiddleware.php:71
- CORE/src/Http/Runner.php:82
- ROOT/vendor/markstory/asset_compress/src/Middleware/AssetCompressMiddleware.php:58
- CORE/src/Http/Runner.php:82
- CORE/src/Error/Middleware/ErrorHandlerMiddleware.php:111
- CORE/src/Http/Runner.php:82
- CORE/src/Http/Runner.php:60
- CORE/src/Http/Server.php:93
- ROOT/webroot/index.php:40
- [main]:

Request URL: /news

I couldn't track the error properly, so I had to downgrade to 5.3.7 to get it up and running again. I am currently in the middle of debugging my code to see where it went sideways with the new version, but haven't found anything helpful besides an assumption that it has something to do with accessing the database.

If it helps: My productive system runs on Debian/MariaDB 10.5.29. Interestingly, my local system runs on Win11/MariaDB 10.4.32 and works just fine with CakePHP 5.4.0.

[ADmad]

@runzinger Yours is a caching issue. Simply clear your cache and the error will be gone.

[runzinger]

@ADmad Wow, that was easy. Can confirm: I deleted everything in /tmp/cache/models and it is working. Thank you!

[dereuromark]

We need to be more clear on the upgrade guides I guess.
The cache issue is going to happen to many on such a changed codebase.

[dereuromark]

This looks like a stale serialized schema dump from a pre-5.4.0 CakePHP, rather than a bug in the diff logic itself.

Index::$accessMethod is a new promoted property in 5.4.0 (PostgreSQL USING / access method support). A promoted default (= null) is only applied when the constructor actually runs.

migrations diff does not rebuild the Index objects through the constructor. It unserializes the migrations schema dump lock file (config/schema-dump-*.lock). PHP's unserialize() skips the constructor, and for typed properties that are absent from the serialized payload it does not apply the declared default either. So if the lock file was written by an older CakePHP (which had no accessMethod key), the unserialized Index ends up with the property in its uninitialized state, and the first read in toArray() throws:

Typed property Cake\Database\Schema\Index::$accessMethod must not be accessed before initialization

MariaDB vs PostgreSQL is not relevant here; the trigger is the outdated lock, not the driver.

Workaround for now: regenerate the dump after upgrading, e.g.

bin/cake migrations dump

(overwrite the stale config/schema-dump-*.lock, once per connection).

Framework-side, Index probably needs a __wakeup() / __unserialize() (or equivalent) that initializes accessMethod for objects unserialized from data that predates the property, since a promoted default cannot cover the unserialize path.

Note: this is my analysis from the source and error, I have not reproduced it. Easy to confirm by checking whether the reporter's lock file predates the 5.4.0 upgrade.

[mirko-pagliai]

As soon as I have this development environment available again (not now), I can confirm whether it was cache and/or try to debug it further.

(I've seen the pull request, and I can also try making a copy of the cache, and try again after applying the pull request to confirm everything)

We need to be more clear on the upgrade guides I guess.

I know it shouldn't be done here, but the rector rule is missing.

Here:
https://book.cakephp.org/5.x/appendices/5-4-migration-guide.html#upgrade-tool

But it's not there:
https://github.com/cakephp/upgrade/tree/5.x/config/rector

It should give errors to other users.

[dereuromark]

Good catch
cakephp/upgrade#408

[mirko-pagliai]

I confirm, unfortunately, that even clearing the entire cache, the problem persists.

$ bin/cake cache clear_all
Clearing default
Cleared default cache
Clearing _cake_translations_
Cleared _cake_translations_ cache
Clearing _cake_model_
Cleared _cake_model_ cache
Clearing _cake_routes_
Cleared _cake_routes_ cache
Clearing mailBoxes
Cleared mailBoxes cache
Clearing hourly
Cleared hourly cache
Clearing daily
Cleared daily cache
Clearing contacts
Cleared contacts cache
Clearing drugs
Cleared drugs cache
Clearing objectives
Cleared objectives cache
Clearing patients
Cleared patients cache
Clearing users
Cleared users cache
Clearing categories
Cleared categories cache
mirko@predator-debian:~/PhpstormProjects/climat$ bin/cake bake migration_diff --generate-only -v SimpleTest
2026-07-23 10:54:03 error: [Error] Typed property Cake\Database\Schema\Index::$accessMethod must not be accessed before initialization in /home/mirko/PhpstormProjects/climat/vendor/cakephp/cakephp/src/Database/Schema/Index.php on line 312
Stack Trace:                                                                                                                                                                                                                                                                                          
- CORE/src/Database/Schema/TableSchema.php:638                                                                                                                                                                                                                                                        
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:470                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:223                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:205                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php:185                                                                                                                                                                                                                       
- ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php:143                                                                                                                                                                                                                         
- ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php:143                                                                                                                                                                                                                       
- CORE/src/Console/BaseCommand.php:261                                                                                                                                                                                                                                                                
- CORE/src/Console/CommandRunner.php:451                                                                                                                                                                                                                                                              
- CORE/src/Console/CommandRunner.php:205                                                                                                                                                                                                                                                              
- ROOT/bin/cake.php:12                                                                                                                                                                                                                                                                                
- [main]:                                                                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                                                      
[Error] Typed property Cake\Database\Schema\Index::$accessMethod must not be accessed before initialization in /home/mirko/PhpstormProjects/climat/vendor/cakephp/cakephp/src/Database/Schema/Index.php on line 312

Stack Trace:

Cake\Database\Schema\Index->toArray() - CORE/src/Database/Schema/TableSchema.php, line 638
Cake\Database\Schema\TableSchema->getIndex() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 470
Migrations\Command\BakeMigrationDiffCommand->getIndexes() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 223
Migrations\Command\BakeMigrationDiffCommand->calculateDiff() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 205
Migrations\Command\BakeMigrationDiffCommand->templateData() - ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php, line 185
Migrations\Command\BakeSimpleMigrationCommand->bake() - ROOT/vendor/cakephp/migrations/src/Command/BakeMigrationDiffCommand.php, line 143
Migrations\Command\BakeMigrationDiffCommand->bake() - ROOT/vendor/cakephp/migrations/src/Command/BakeSimpleMigrationCommand.php, line 143
Migrations\Command\BakeSimpleMigrationCommand->execute() - CORE/src/Console/BaseCommand.php, line 261
Cake\Console\BaseCommand->run() - CORE/src/Console/CommandRunner.php, line 451
Cake\Console\CommandRunner->runCommand() - CORE/src/Console/CommandRunner.php, line 205
Cake\Console\CommandRunner->run() - ROOT/bin/cake.php, line 12
[main] - [main], line 0

I also tried manually deleting tmp/cache.

I confirm that by applying the PR, the problem is solved.

If I can do any more debugging without PR and if it would be helpful, please let me know.

[dereuromark]

Your problem is not the cache but the lock file.
See above for the correct command to run.