[Config] Fix array shape generation for backed enums #62563

OskarStark · 2025-11-29T10:31:43Z

Q	A
Branch?	7.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Issues	--
License	MIT

Spotted in symfony/ai#1013 ➡️ https://github.com/symfony/ai/actions/runs/19780810683/job/56680686767?pr=1013

It works for redis, but not for postgres, because redis is using ->values(Distance::cases()) and postgres is using ->enumFqcn(PostgresDistance::class):

Redis

Enum

enum Distance: string
{
    use Comparable;

    case Cosine = 'COSINE';
    case L2 = 'L2';
    case Ip = 'IP';
}

Config

->enumNode('distance')
    ->info('Distance metric to use for vector similarity search')
    ->values(Distance::cases())
    ->defaultValue(Distance::Cosine)
->end()

RESULT

 *         redis?: array<string, array{ // Default: []
 *             connection_parameters?: mixed, // see https://github.com/phpredis/phpredis?tab=readme-ov-file#example-1
 *             client?: string, // a service id of a Redis client
 *             index_name: string,
 *             key_prefix?: string, // Default: "vector:"
 *             distance?: \Symfony\AI\Store\Bridge\Redis\Distance::Cosine|\Symfony\AI\Store\Bridge\Redis\Distance::L2|\Symfony\AI\Store\Bridge\Redis\Distance::Ip, // Distance metric to use for vector similarity search // Default: "COSINE"
 *         }>,

Postgres

Enum

enum Distance: string
{
    use Comparable;

    case Cosine = 'cosine';
    case InnerProduct = 'inner_product';
    case L1 = 'l1';
    case L2 = 'l2';

    public function getComparisonSign(): string
    {
        return match ($this) {
            self::Cosine => '<=>',
            self::InnerProduct => '<#>',
            self::L1 => '<+>',
            self::L2 => '<->',
        };
    }
}

Config

->enumNode('distance')
    ->info('Distance metric to use for vector similarity search')
    ->enumFqcn(PostgresDistance::class)
    ->defaultValue(PostgresDistance::L2)
->end()

RESULT

 *         postgres?: array<string, array{ // Default: []
 *             dsn?: string,
 *             username?: string,
 *             password?: string,
 *             table_name: string,
 *             vector_field?: string,
 *             distance?: cosine|inner_product|l1|l2, // Distance metric to use for vector similarity search // Default: "l2"
 *             dbal_connection?: string,
 *         }>,

you can see, that the result is different:
FQCN:
distance?: \Symfony\AI\Store\Bridge\Redis\Distance::Cosine|\Symfony\AI\Store\Bridge\Redis\Distance::L2|\Symfony\AI\Store\Bridge\Redis\Distance::Ip,
vs. strings:
distance?: cosine|inner_product|l1|l2,

Why?

src/Symfony/Component/Config/Definition/ArrayShapeGenerator.php

src/Symfony/Component/Config/Tests/Fixtures/StringBackedTestEnum.php

alexandre-daubois · 2025-12-01T08:08:40Z

you can see, that the result is different

The reason is that EnumNode exists for quite some time now and it was used before enum were introduced to only accept a set of scalar values (but no native enum support). Providing ->values(Enum::cases()) set the enum cases as permissible values. Using enumFqcn is actually quite different as it converts each enum case to their scalar value:

    public function getPermissibleValues(string $separator, bool $trim = true): string
    {
        if (is_subclass_of($this->enumFqcn, \BackedEnum::class)) {
            return implode($separator, array_column($this->enumFqcn::cases(), 'value'));
        }

        // ...
    }

I think it is better because when dealing with configuration, you don't necessarily want to expose the whole underlying enum FQCN and deal with long class names. Hope this helps!

stof · 2025-12-01T13:43:26Z

When using enumFqcn, the config actually accepts both the backing values or an enum instance. So the generated type should combine the set of backing values and the enum FQCN (or it should even generated it as value-of<EnumFqcn>|EnumFqcn, relying on the value-of<> type supported by all SA tools, instead of resolving the list of backing values manually).

OskarStark · 2025-12-01T15:57:20Z

So my fix is correct, when I interpret your comment @alexandre-daubois, right?

While @stof your comment is an improvement I can implement if wanted

src/Symfony/Component/Config/Definition/EnumNode.php

OskarStark · 2025-12-04T06:49:12Z

When using enumFqcn, the config actually accepts both the backing values or an enum instance. So the generated type should combine the set of backing values and the enum FQCN (or it should even generated it as value-of|EnumFqcn, relying on the value-of<> type supported by all SA tools, instead of resolving the list of backing values manually).

Like this @stof ?

alexandre-daubois

Looks good! 🙂

src/Symfony/Component/Config/Definition/EnumNode.php

nicolas-grekas

Minor suggestion. Also: tests are failing.

--- a/src/Symfony/Component/Config/Definition/EnumNode.php
+++ b/src/Symfony/Component/Config/Definition/EnumNode.php
@@ -85,14 +85,12 @@ class EnumNode extends ScalarNode

             $values = array_column($this->enumFqcn::cases(), 'value');

-            return implode($separator, array_map(static function ($value) {
-                return json_encode($value, \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE);
-            }, $values));
+            return implode($separator, array_map(static fn ($value) => json_encode($value, \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE), $values));
         }

         return implode($separator, array_unique(array_map(static function ($value) use ($trim) {
             if (!$value instanceof \UnitEnum) {
-                return json_encode($value);
+                return json_encode($value, \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE | \JSON_PRESERVE_ZERO_FRACTION);
             }

             return $trim ? ltrim(var_export($value, true), '\\') : var_export($value, true);

OskarStark · 2025-12-04T18:49:10Z

Failures unrelated

nicolas-grekas · 2025-12-05T07:52:12Z

Thank you @OskarStark.

…karStark) This PR was merged into the main branch. Discussion ---------- Use Symfony 7.4 for demo, examples and ai.symfony.com | Q | A | ------------- | --- | Bug fix? | no | New feature? | no | Docs? | no | Issues | -- | License | MIT ### Needs - [x] symfony/symfony#62563 Commits ------- ab840cc minor: Require Symfony 7.4 as minimum version

carsonbot added Status: Needs Review Bug Config labels Nov 29, 2025

carsonbot added this to the 7.4 milestone Nov 29, 2025

OskarStark requested review from alexandre-daubois and chr-hertel November 29, 2025 10:31

OskarStark mentioned this pull request Nov 29, 2025

Use Symfony 7.4 for demo, examples and ai.symfony.com symfony/ai#1013

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OskarStark requested review from alexandre-daubois and stof December 4, 2025 18:44

[Config] Fix array shape generation for backed enums

62422c4

nicolas-grekas force-pushed the fix/backend-enums branch from b7ee321 to 62422c4 Compare December 5, 2025 07:52

nicolas-grekas merged commit 3ad9f69 into symfony:7.4 Dec 5, 2025
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This was referenced Dec 7, 2025

Release v7.4.1 #62679

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Release v8.0.1 #62680

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[Config] Fix array shape generation for backed enums #62563

[Config] Fix array shape generation for backed enums #62563

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OskarStark commented Nov 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Redis

Enum

Config

RESULT

Postgres

Enum

Config

RESULT

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alexandre-daubois commented Dec 1, 2025

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OskarStark commented Nov 29, 2025 •

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