Constraints from packageRules don't override global constraints

[eliashaeussler]

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Please tell us more about your question or problem

Problem

I have two constraints in my renovate.json:

{
    "constraints": {
        "php": "8.1.*"
    },
    "packageRules": [
        {
            "matchFileNames": [
                "foo/**"
            ],
            "constraints": {
                "php": "8.3.*"
            }
        }
    ]
}

My expectation is that (at least since #29533) package updates for the foo/composer.json and foo/composer.lock files use PHP 8.3 whereas all other files like composer.json and composer.lock use PHP 8.1.

However, it seems like Renovate uses the global constraints object for all package updates.

Minimal reproduction repo

Repo: https://github.com/eliashaeussler/renovate-repro-constraints

Example: eliashaeussler/renovate-repro-constraints#3 is a great example where Renovate downgrades packages in foo/composer.lock to PHPUnit ^10 because PHPUnit ^11 is not compatible with PHP 8.1, which is obviously used instead of the configured 8.3.*.

Logs (if relevant)

Logs

DEBUG: Repository config
{
  "fileName": "renovate.json"
  "config": {
    "$schema": "https://docs.renovatebot.com/renovate-schema.json",
    "extends": [
      "config:recommended"
    ],
    "constraints": {
      "php": "8.1.*"
    },
    "lockFileMaintenance": {
      "enabled": true
    },
    "packageRules": [
      {
        "matchFileNames": [
          "foo/**"
        ],
        "constraints": {
          "php": "8.3.*"
        }
      }
    ]
  }
}

// ...

DEBUG: updateArtifacts for updatedPackageFiles (branch="renovate/phpunit-phpunit-12.x")
DEBUG: composer.updateArtifacts(composer.json) (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using php constraint from config (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using GitHub Server-to-Server token (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Setting CONTAINERBASE_CACHE_DIR to /tmp/renovate/cache/containerbase (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using containerbase dynamic installs (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Resolved stable matching version (branch="renovate/phpunit-phpunit-12.x")
{
  "toolName": "php"
  "constraint": "8.1.*"
  "resolvedVersion": "8.1.31"
}

DEBUG: Resolved stable matching version (branch="renovate/phpunit-phpunit-12.x")
{
  "toolName": "composer"
  "constraint": "^2.6"
  "resolvedVersion": "2.8.5"
}

DEBUG: Executing command (branch="renovate/phpunit-phpunit-12.x")
{
  "command": "install-tool php 8.1.31"
}

// ...

DEBUG: composer.updateArtifacts(foo/composer.json) (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using php constraint from config (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using GitHub Server-to-Server token (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Setting CONTAINERBASE_CACHE_DIR to /tmp/renovate/cache/containerbase (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Using containerbase dynamic installs (branch="renovate/phpunit-phpunit-12.x")
DEBUG: Resolved stable matching version (branch="renovate/phpunit-phpunit-12.x")
{
  "toolName": "php"
  "constraint": "8.1.*"
  "resolvedVersion": "8.1.31"
}

DEBUG: Resolved stable matching version (branch="renovate/phpunit-phpunit-12.x")
{
  "toolName": "composer"
  "constraint": "^2.6"
  "resolvedVersion": "2.8.5"
}

DEBUG: Executing command (branch="renovate/phpunit-phpunit-12.x")
{
  "command": "install-tool php 8.1.31"
}