feat(unstable): ability to `npm install` then `deno run main.ts` (#20967)

This PR adds a new unstable "bring your own node_modules" (BYONM)
functionality currently behind a `--unstable-byonm` flag (`"unstable":
["byonm"]` in a deno.json).

This enables users to run a separate install command (ex. `npm install`,
`pnpm install`) then run `deno run main.ts` and Deno will respect the
layout of the node_modules directory as setup by the separate install
command. It also works with npm/yarn/pnpm workspaces.

For this PR, the behaviour is opted into by specifying
`--unstable-byonm`/`"unstable": ["byonm"]`, but in the future we may
make this the default behaviour as outlined in
https://github.com/denoland/deno/issues/18967#issuecomment-1761248941

This is an extremely rough initial implementation. Errors are
terrible in this and the LSP requires frequent restarts. Improvements
will be done in follow up PRs.

1 files changed, 6 insertions, 17 deletions

diff --git a/cli/npm/managed/resolvers/local.rs b/cli/npm/managed/resolvers/local.rs
index 2d774518a..a4a8550f1 100644
--- a/cli/npm/managed/resolvers/local.rs
+++ b/cli/npm/managed/resolvers/local.rs
@@ -36,7 +36,6 @@ use deno_runtime::deno_core::futures;
 use deno_runtime::deno_fs;
 use deno_runtime::deno_node::NodePermissions;
 use deno_runtime::deno_node::NodeResolutionMode;
-use deno_runtime::deno_node::PackageJson;
 use deno_semver::package::PackageNv;
 use serde::Deserialize;
 use serde::Serialize;
@@ -181,23 +180,8 @@ impl NpmPackageFsResolver for LocalNpmPackageResolver {
       } else {
         Cow::Owned(current_folder.join("node_modules"))
       };
-      let sub_dir = join_package_name(&node_modules_folder, name);
-      if self.fs.is_dir_sync(&sub_dir) {
-        // if doing types resolution, only resolve the package if it specifies a types property
-        if mode.is_types() && !name.starts_with("@types/") {
-          let package_json = PackageJson::load_skip_read_permission(
-            &*self.fs,
-            sub_dir.join("package.json"),
-          )?;
-          if package_json.types.is_some() {
-            return Ok(sub_dir);
-          }
-        } else {
-          return Ok(sub_dir);
-        }
-      }
 
-      // if doing type resolution, check for the existence of a @types package
+      // attempt to resolve the types package first, then fallback to the regular package
       if mode.is_types() && !name.starts_with("@types/") {
         let sub_dir =
           join_package_name(&node_modules_folder, &types_package_name(name));
@@ -206,6 +190,11 @@ impl NpmPackageFsResolver for LocalNpmPackageResolver {
         }
       }
 
+      let sub_dir = join_package_name(&node_modules_folder, name);
+      if self.fs.is_dir_sync(&sub_dir) {
+        return Ok(sub_dir);
+      }
+
       if current_folder == self.root_node_modules_path {
         bail!(
           "could not find package '{}' from referrer '{}'.",