1516352 - Avoid the need to re-run `yarn` when modifying a library

Status: RESOLVED FIXED

(Taskcluster :: Services, enhancement)

Description

[Dustin J. Mitchell [:dustin] (he/him)]

With the current monorepo arrangement, if service X has

  "taskcluster-lib-foo": "file:../libraries/foo"

in its package.json, then `yarn` helpfully *copies* foo into services/X/node_modules/taskcluster-lib-foo.  It will re-copy it when running `yarn`, but without a `yarn` run changes to tc-lib-foo won't be reflected in service X.

Let's find a way to fix that, such that a change to something under libraries/ has immediate effect under services/.

Note that this is not blocking the monorepo deployment.. it's something we can solve afterward.

Comment 2

[Dustin J. Mitchell [:dustin] (he/him)]

It doesn't seem to re-copy automatically.  You need to run `yarn clean` then `yarn` again.

Comment 3

[Hassan Ali (:hassan)]

(In reply to Dustin J. Mitchell [:dustin] pronoun: he from comment #0)
> With the current monorepo arrangement, if service X has
> 
>   "taskcluster-lib-foo": "file:../libraries/foo"
> 
> in its package.json, then `yarn` helpfully *copies* foo into
> services/X/node_modules/taskcluster-lib-foo.  It will re-copy it when
> running `yarn`, but without a `yarn` run changes to tc-lib-foo won't be
> reflected in service X.

I think what we want is the folder to be symlinked. npm seem to use the `file:` protocol whereas yarn uses `link:` to identify which packages to symlink. I see two options:

1. Switch `file:` to `link:`. I don't think the link protocol works with npm so something like `npm install` would fail, but that's okay since we use yarn.
2. Write a script[1]

[1] https://github.com/milesj/beemo/blob/master/scripts/link-packages.sh

Comment 4

[Brian Stack [:bstack]]

https://github.com/taskcluster/taskcluster/pull/52