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Exploration: Composer Path Repositories for Local Drupal Module Dependencies

· 3 min read
VictorStackAI
VictorStackAI
VictorStackAI

The Hook When one Drupal module depends on another, I want to iterate across both without publishing interim versions or wiring up a private Composer repo. Path repositories give me that speed while keeping dependency boundaries honest.

Why I Built It I explored how Composer path repositories can simplify local Drupal module development when one module depends on another. The goal is to iterate across modules without publishing interim versions or wiring up a private Composer repo, while still mimicking production resolution.

The Solution Why Path Repositories Work Well for Drupal Drupal modules are Composer packages. If module-a requires module-b, you can point the consuming site to a local checkout of module-b during development, while keeping production on a tagged release. This keeps module boundaries clean and mirrors how dependency resolution will behave in production.

Minimal Setup (Composer Root) Add a path repository entry in the project’s root composer.json:

{
  "repositories": [
    {
      "type": "path",
      "url": "../modules/module-b",
      "options": {
        "symlink": true
      }
    }
  ]
}

Then require the package as normal:

composer require vendor/module-b:@dev

With symlink: true, changes in module-b are immediately visible to the consuming project.

Module Composer.json (Dependency Side) In module-a/composer.json, declare the dependency normally:

{
  "require": {
    "vendor/module-b": "^1.2"
  }
}

During development, the path repository overrides that constraint with your local checkout. In production, Composer resolves to the tagged version from the main repo.

Workflow Notes

  • Keep package names and versions consistent across module repos so resolution behaves as expected.
  • Use @dev only in the root project, not in module repositories, to avoid leaking dev constraints into releases.
  • If you need to test multiple dependency branches, switch the local checkout and run composer update vendor/module-b to refresh the lock file.

Common Pitfalls

  • If module-b isn’t a valid Composer package (missing composer.json or name), the path repo won’t resolve.
  • If symlinks aren’t supported (some CI environments), set symlink: false or omit the option.
  • If you forget to remove the path repository before releasing the site, you can accidentally pin to a local path in composer.lock.

The Code I built a small Drupal module dependency demo that shows the path repository setup end to end. You can clone it, run through the Composer workflow, and browse the key files here: View Code

What I Learned Path repositories are a clean way to keep Drupal module dependencies modular while still enabling fast local iteration. They mirror production resolution closely, but only if you keep package metadata consistent and avoid dev constraints leaking into module releases.

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