From 97ffd7ec18a737ac93a5765e6da42f71f4a87de4 Mon Sep 17 00:00:00 2001
From: MT Lewis <mtlewis@users.noreply.github.com>
Date: Tue, 16 Apr 2024 21:45:07 +0100
Subject: [PATCH] yarn-plugin: replace backstage:^ with ^ ranges when packing

Signed-off-by: MT Lewis <mtlewis@users.noreply.github.com>
---
 .../src/handlers/beforeWorkspacePacking.ts    | 25 ++++++---
 .../src/resolver/BackstageResolver.ts         |  6 +--
 packages/yarn-plugin/src/util.ts              | 51 ++++++++-----------
 3 files changed, 43 insertions(+), 39 deletions(-)

diff --git a/packages/yarn-plugin/src/handlers/beforeWorkspacePacking.ts b/packages/yarn-plugin/src/handlers/beforeWorkspacePacking.ts
index a98e8270a1..e9f46a6159 100644
--- a/packages/yarn-plugin/src/handlers/beforeWorkspacePacking.ts
+++ b/packages/yarn-plugin/src/handlers/beforeWorkspacePacking.ts
@@ -15,7 +15,7 @@
  */
 
 import { Descriptor, Workspace, structUtils } from '@yarnpkg/core';
-import { inferPackageVersion } from '../util';
+import { getCurrentBackstageVersion, getPackageVersion } from '../util';
 import { PROTOCOL } from '../constants';
 
 const getFinalDependencyType = (
@@ -43,21 +43,34 @@ export const beforeWorkspacePacking = async (
     'devDependencies',
     'peerDependencies',
   ] as const) {
+    const backstageVersion = getCurrentBackstageVersion();
+
     const entries = Array.from(
       workspace.manifest.getForScope(dependencyType).values(),
-    ).filter(descriptor => descriptor.range === `${PROTOCOL}^`);
+    ).filter(descriptor => descriptor.range.startsWith(PROTOCOL));
 
     for (const descriptor of entries) {
+      const ident = structUtils.stringifyIdent(descriptor);
+      const range = structUtils.parseRange(descriptor.range);
+
+      if (range.selector !== '^') {
+        throw new Error(
+          `Unexpected version range "${descriptor.range}" for dependency on "${ident}"`,
+        );
+      }
+
       const finalDependencyType = getFinalDependencyType(
         dependencyType,
         descriptor,
         workspace,
       );
-      const ident = structUtils.stringifyIdent(descriptor);
 
-      rawManifest[finalDependencyType][ident] = await inferPackageVersion(
-        descriptor,
-      );
+      rawManifest[finalDependencyType][ident] = `^${await getPackageVersion(
+        structUtils.makeDescriptor(
+          descriptor,
+          `${PROTOCOL}${backstageVersion}`,
+        ),
+      )}`;
     }
   }
 };
diff --git a/packages/yarn-plugin/src/resolver/BackstageResolver.ts b/packages/yarn-plugin/src/resolver/BackstageResolver.ts
index 61fbdab58e..fa51ceb880 100644
--- a/packages/yarn-plugin/src/resolver/BackstageResolver.ts
+++ b/packages/yarn-plugin/src/resolver/BackstageResolver.ts
@@ -22,7 +22,7 @@ import {
   Resolver,
 } from '@yarnpkg/core';
 import { PROTOCOL } from '../constants';
-import { inferBackstageVersion, inferPackageVersion } from '../util';
+import { getCurrentBackstageVersion, getPackageVersion } from '../util';
 
 export class BackstageResolver implements Resolver {
   static protocol = PROTOCOL;
@@ -35,7 +35,7 @@ export class BackstageResolver implements Resolver {
   bindDescriptor(descriptor: Descriptor): Descriptor {
     return structUtils.makeDescriptor(
       descriptor,
-      `${PROTOCOL}${inferBackstageVersion(descriptor)}`,
+      `${PROTOCOL}${getCurrentBackstageVersion()}`,
     );
   }
 
@@ -43,7 +43,7 @@ export class BackstageResolver implements Resolver {
     return [
       structUtils.makeLocator(
         descriptor,
-        `npm:${await inferPackageVersion(descriptor)}`,
+        `npm:${await getPackageVersion(descriptor)}`,
       ),
     ];
   }
diff --git a/packages/yarn-plugin/src/util.ts b/packages/yarn-plugin/src/util.ts
index ae11019c66..3e4e795c89 100644
--- a/packages/yarn-plugin/src/util.ts
+++ b/packages/yarn-plugin/src/util.ts
@@ -14,49 +14,40 @@
  * limitations under the License.
  */
 
-import { Descriptor, structUtils } from '@yarnpkg/core';
 import { npath, xfs } from '@yarnpkg/fslib';
 import { valid as semverValid } from 'semver';
 import { getManifestByVersion } from '@backstage/release-manifests';
+import { Descriptor, structUtils } from '@yarnpkg/core';
 import { PROTOCOL } from './constants';
 
-export const inferBackstageVersion = (descriptor: Descriptor) => {
+export const getCurrentBackstageVersion = () => {
+  const backstageJson = xfs.readJsonSync(
+    npath.toPortablePath('./backstage.json'),
+  );
+
+  const backstageVersion = semverValid(backstageJson.version);
+
+  if (backstageVersion === null) {
+    throw new Error('Valid version string not found in backstage.json');
+  }
+
+  return backstageVersion;
+};
+
+export const getPackageVersion = async (descriptor: Descriptor) => {
+  const ident = structUtils.stringifyIdent(descriptor);
   const range = structUtils.parseRange(descriptor.range);
 
   if (range.protocol !== PROTOCOL) {
-    throw new Error(
-      `inferBackstageVersion called with unexpected protocol ${range.protocol}`,
-    );
+    throw new Error(`Unexpected ${range.protocol} range when packing`);
   }
 
-  let selector = range.selector;
-
-  // For backstage:^ we look up the version from backstage.json
-  if (selector === `^`) {
-    const backstageJson = xfs.readJsonSync(
-      npath.toPortablePath('./backstage.json'),
-    );
-
-    selector = backstageJson.version;
+  if (!semverValid(range.selector)) {
+    throw new Error(`Missing backstage version in range ${descriptor.range}`);
   }
 
-  if (!semverValid(selector)) {
-    throw new Error(
-      `Invalid "backstage:" version string found for ${structUtils.stringifyIdent(
-        descriptor,
-      )}. Version must be either "backstage:*" or "backstage:<version>", where version is a single Backstage release version.`,
-    );
-  }
-
-  return selector;
-};
-
-export const inferPackageVersion = async (descriptor: Descriptor) => {
-  const ident = structUtils.stringifyIdent(descriptor);
-  const backstageVersion = inferBackstageVersion(descriptor);
-
   const manifest = await getManifestByVersion({
-    version: backstageVersion,
+    version: range.selector,
   });
 
   const manifestEntry = manifest.packages.find(