viv

Using viv as composer

make install-shim installs a composer binary next to viv. Plain make install installs viv only, and refreshes the shim only if one is already there, so it never replaces your real Composer. Put it on PATH ahead of the real Composer, or symlink it as composer in CI: everyday install, dump-autoload, normalize and create-project run through viv; every other command falls through to your real Composer install.1

This is also the cheapest way to check whether a project migrates cleanly: alias composer to the shim and run your existing scripts unedited.

In GitHub Actions, one step installs viv and puts the shim first on PATH, so an existing composer install step runs through viv unedited:

- uses: svandragt/vivace/action@v0
- run: composer install --no-dev

The action downloads the release tarball for the runner's OS and architecture, checks it against the release's SHA256SUMS, and installs nothing else. Pin a release with with: { version: v0.21.0 }; set shim: false to get viv on PATH without the composer shim. Cache viv's store with actions/cache on ~/.cache/vivace, keyed on composer.lock.

A command or flag the shim doesn't understand falls back to the real Composer with a note on stderr naming what wasn't understood, so a migration that quietly stopped using viv is visible instead of just slower. Set VIV_SHIM_STRICT=1 to make that fallback a hard error instead, for a CI job that wants a red build rather than a silent return to Composer.

You can also point a script straight at viv. The CI idiom --prefer-dist --no-interaction --no-progress already describes what viv does, so viv install and viv dump-autoload accept those flags and ignore them instead of failing.

  1. The shim maps install, dump-autoload, normalize, create-project, update, require and remove with their supported flags (update's partial-update package arguments and -w/-W included) to viv; everything else, search, an unrecognised flag, it hands through to the real Composer binary unchanged. Point VIV_COMPOSER_PATH at the real binary if it isn't first on PATH. The shim only has something to hand through to if a real Composer is on PATH in the first place: if there isn't one, those commands fail rather than silently falling back to viv. composer --version is the exception: it prints viv <version> (composer shim), then the real Composer's own version if one is on PATH, and exits 0 either way. ↩

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