Add Pin Specific pnpm Version For Builds as a Vercel TIL

vercel/pin-specific-pnpm-version-for-builds.md

@@ -0,0 +1,35 @@
+# Pin Specific pnpm Version For Builds
+
+Vercel recognizes when [a project contain a `pnpm-lock.yaml`
+file](https://vercel.com/changelog/projects-using-pnpm-can-now-be-deployed-with-zero-configuration)
+and will automatically use [`pnpm`](https://pnpm.io/) for builds of that
+project.
+
+It looks for [the `lockfileVersion` in `pnpm-lock.yaml` to determine what major
+version of `pnpm` to
+install](https://vercel.com/docs/concepts/deployments/configure-a-build#install-command).
+If the `lockfileVersion` is `5.4`, then it will use the latest pnpm v7.
+Otherwise it will fallback to the latest pnpm v6.
+
+That's the extent of the control you have over the `pnpm` version. That is,
+unless you are to use [this experimental corepack
+feature](https://vercel.com/docs/concepts/deployments/configure-a-build#corepack).
+Set the `ENABLE_EXPERIMENTAL_COREPACK` environment variable to `1` in your
+project's _Environment Variables_ under _Settings_.
+
+Then specify the `pnpm` version with the `packageManager` key in your
+`package.json`.
+
+```json
+{
+  "packageManager": "pnpm@7.13.2"
+}
+```
+
+Even though the current latest is `7.13.5`, Vercel will see the Corepack
+environment variables and the `packageManager` version and use `7.13.2`
+instead.
+
+See [this PR](https://github.com/skillrecordings/products/pull/535) and [this
+issue](https://github.com/prisma/prisma/issues/12921#issuecomment-1284425847)
+for more details.