Tested on https://github.com/composer/composer, build and devShell both work as expected.

• Add php examples (need the builder merged first)

That should not be necessary. You can add the example flake under /examples/php/flake.nix, and then execute from the repo root: nix run .#tests-examples php

Alternatively navigate to /examples/php, then run:
nix flake lock --override-input dream2nix ../../
and
nix run .#resolveImpre / nix build ..etc.

I just added an example via e77c129. Working fine.

It seems like the composer example adds significant overhead to the test execution.
https://github.com/nix-community/dream2nix/runs/8303370789?check_suite_focus=true#step:5:3143
That is probably because of the slow nix git fetching. Maybe we can replace the example with a project, that doesn't have many dependencies.

@DavHau
I've disabled checks on the composer example, which speeds it up a little.
Running the tests locally I get:

Execution times:
1 sec: _d2n-indexer
37 sec: php_composer        <<--
44 sec: nodejs_workspace
52 sec: _d2n-extended-new-subsystem
56 sec: _d2n-init-pkgs
56 sec: rust_ripgrep
83 sec: nodejs_prettier
85 sec: _d2n-extended
131 sec: nodejs_eslint
143 sec: debian-binary
144 sec: rust_set-rust-toolchain
155 sec: rust_no-cargo-lock
163 sec: nodejs_mattermost-webapp
175 sec: python_aiohttp
209 sec: haskell_stack-lock
210 sec: nodejs_eslint-aggreagted
281 sec: haskell_cabal-plan

But does not seem to have any effect on the CI time.

Thanks for this, I recently tried this builder on one of the projects but got this error:

error: Constraint "as" could not be parsed

The project composer.json uses aliases as described here:
https://getcomposer.org/doc/articles/aliases.md#aliases

@aszenz
Thank you for noticing and reporting this.
The builder does not handle some less-common composer features at the moment (like composer plugins, php version constraints, composer api, aliases, update/install script hooks, ...).
Could you link to the project or if it's a private, make a small example of the composer.json that produces this error?

@aszenz Thank you for noticing and reporting this. The builder does not handle some less-common composer features at the moment (like composer plugins, php version constraints, composer api, aliases, update/install script hooks, ...). Could you link to the project or if it's a private, make a small example of the composer.json that produces this error?

Sure here's a sample project on which running nix build .#packages.x86_64-linux.app/php fails with:
error: Constraint "as" could not be parsed

https://github.com/aszenz/php-app-nix

If i remove the as then i get an error about missing extensions, seems like the php extensions mentioned in composer.json are not available when the build runs

@aszenz
#296 fixes both issues (inline version alias, extra php extenstions)