Adopt pnpm overrides from root package manifest (#62)

src/isolate.ts

@@ -156,11 +156,12 @@ export async function isolate(
    * Copy the target manifest file to the isolate location and adapt its
    * workspace dependencies to point to the isolated packages.
    */
-  await adaptTargetPackageManifest(
-    targetPackageManifest,
+  await adaptTargetPackageManifest({
+    manifest: targetPackageManifest,
     packagesRegistry,
-    isolateDir
-  );
+    isolateDir,
+    workspaceRootDir,
+  });
 
   /** Generate an isolated lockfile based on the original one */
   const usedFallbackToNpm = await processLockfile({

src/lib/manifest/adapt-target-package-manifest.ts

@@ -3,6 +3,7 @@ import { useConfig } from "../config";
 import { usePackageManager } from "../package-manager";
 import type { PackageManifest, PackagesRegistry } from "../types";
 import { adaptManifestInternalDeps } from "./helpers";
+import { adoptPnpmFieldsFromRoot } from "./helpers/adopt-pnpm-fields-from-root";
 import { writeManifest } from "./io";
 
 /**
@@ -12,11 +13,17 @@ import { writeManifest } from "./io";
  * - The devDependencies are possibly removed
  * - Scripts are picked or omitted and otherwise removed
  */
-export async function adaptTargetPackageManifest(
-  manifest: PackageManifest,
-  packagesRegistry: PackagesRegistry,
-  isolateDir: string
-) {
+export async function adaptTargetPackageManifest({
+  manifest,
+  packagesRegistry,
+  isolateDir,
+  workspaceRootDir,
+}: {
+  manifest: PackageManifest;
+  packagesRegistry: PackagesRegistry;
+  isolateDir: string;
+  workspaceRootDir: string;
+}) {
   const packageManager = usePackageManager();
   const { includeDevDependencies, forceNpm, pickFromScripts, omitFromScripts } =
     useConfig();
@@ -30,9 +37,10 @@ export async function adaptTargetPackageManifest(
     packageManager.name === "pnpm" && !forceNpm
       ? /**
          * For PNPM the output itself is a workspace so we can preserve the specifiers
-         * with "workspace:*" in the output manifest.
+         * with "workspace:*" in the output manifest, but we do want to adopt the
+         * pnpm.overrides field from the root package.json.
          */
-        inputManifest
+        await adoptPnpmFieldsFromRoot(inputManifest, workspaceRootDir)
       : /** For other package managers we replace the links to internal dependencies */
         adaptManifestInternalDeps({
           manifest: inputManifest,

src/lib/manifest/helpers/adopt-pnpm-fields-from-root.ts

@@ -0,0 +1,31 @@
+import type { ProjectManifest } from "@pnpm/types";
+import path from "path";
+import type { PackageManifest } from "~/lib/types";
+import { readTypedJson } from "~/lib/utils";
+
+/**
+ * Adopts the `pnpm` fields from the root package manifest. Currently it only
+ * takes overrides, because I don't know if any of the others are useful or
+ * desired.
+ */
+export async function adoptPnpmFieldsFromRoot(
+  targetPackageManifest: PackageManifest,
+  workspaceRootDir: string
+) {
+  const rootPackageManifest = await readTypedJson<ProjectManifest>(
+    path.join(workspaceRootDir, "package.json")
+  );
+
+  const overrides = rootPackageManifest.pnpm?.overrides;
+
+  if (!overrides) {
+    return targetPackageManifest;
+  }
+
+  return {
+    ...targetPackageManifest,
+    pnpm: {
+      overrides,
+    },
+  };
+}