[Question] Shouldn't this also be listed inpeerDependencies? Even if listing it inpeerDependenciesMeta implicitly adds it there, it feels odd to me to make that implicit.

I just copied this fromtype-utils (which is where the missing dep for typescript comes from), which also does not list it as an explicit peerdep

Ha, nice, so this might be an existing issue in that package then? My vote is to fix in both packages.

Just came here to say that appearently at least both Yarn and pnpm have opted in the past to have "peerDependenciesMeta withoutpeerDependencies" imply a peer dependency on*. This was done due to some (legacy?) npm behavior regarding peer dependencies, making package authors hesistant to list them. Seepnpm/pnpm#2128.

But it's probably a better practice to explicitly list them; and given the age of the referenced issue probably safe enough as well.

The reason we usedpeerDependenciesMeta withoutpeerDependencies was because there were versions of npm that did not supportpeerDependenciesMeta. This meant that when we used an explicitpeerDependencies then users would be spammed with warnings saying they didn't have TS installed. This was a problem as some big packages included our plugins by default but only used them if the user opted in to TS which caused non-TS users to get spammed with missing peer dep errors.

A this point we could probably also include the explicitpeerDependencies on TS but also there's no harm in not including it and having it inferred to ensure that nobody gets spammed with logs.

Do you know ifnpm also shares this behavior ofpeerDependenciesMeta implyingpeerDependencies? From a cursory search of the npm sources it seems to me like it doesn't:https://github.com/npm/cli/blob/75a3f1228865f426d8790be27f1258e501f2c450/workspaces/arborist/lib/node.js#L859-L871

Anyways, what do we think of merging this PR first and moving the discussion about whether or not to list an explicit peerdep to a different issue? We don't need to block fixing users' warnings on figuring out the proper manifest declarations 😅

I'm 👍 on that. If nobody else weighs in with a contrary opinion by our weekly release midday Monday EST then we can just merge as-is.

Now that you mention it, I do like the idea of having one release just addingpeerDependenciesMeta, then a subsequent release addingpeerDependencies on top. Just in case there's some bizarre edge case bug with the latter.