fix(changeset-preview): match get-release-plan to the repo's changesets major

.github/changeset-preview/package.json

@@ -1,5 +1,6 @@
 {
   "dependencies": {
-    "@changesets/get-release-plan": "^4.0.16"
+    "get-release-plan-v4": "npm:@changesets/get-release-plan@^4.0.16",
+    "get-release-plan-v5": "npm:@changesets/get-release-plan@^5.0.2"
   }
 }

.github/changeset-preview/preview-changeset-versions.mjs

@@ -4,15 +4,56 @@
  * Uses `@changesets/get-release-plan` to get the version bumps and formats it as markdown.
  */
 
-import { writeFileSync } from 'node:fs'
-import { resolve } from 'node:path'
+import { readFileSync, writeFileSync } from 'node:fs'
+import { createRequire } from 'node:module'
+import { join, resolve } from 'node:path'
 import { parseArgs } from 'node:util'
-import getReleasePlan from '@changesets/get-release-plan'
 
 const GITHUB_WORKSPACE = resolve(process.env.GITHUB_WORKSPACE)
 
 console.log(`Using workspace: ${GITHUB_WORKSPACE}`)
 
+/**
+ * Release plan semantics differ between changesets majors (e.g. v2 bumps peer
+ * dependents to major unless `onlyUpdatePeerDependentsWhenOutOfRange` is set,
+ * v3 doesn't), so use the `get-release-plan` major that matches the
+ * `@changesets/cli` the workspace actually releases with.
+ */
+const RELEASE_PLAN_BY_CLI_MAJOR = {
+  2: 'get-release-plan-v4',
+  3: 'get-release-plan-v5',
+}
+const DEFAULT_CLI_MAJOR = 3
+
+function getChangesetsCliMajor() {
+  try {
+    const require = createRequire(join(GITHUB_WORKSPACE, 'package.json'))
+    const pkgPath = require.resolve('@changesets/cli/package.json')
+    const { version } = JSON.parse(readFileSync(pkgPath, 'utf8'))
+    console.log(`Found @changesets/cli@${version}`)
+    return Number(version.split('.')[0])
+  } catch {
+    console.warn(
+      `Could not resolve @changesets/cli from workspace, assuming v${DEFAULT_CLI_MAJOR}`,
+    )
+    return DEFAULT_CLI_MAJOR
+  }
+}
+
+async function loadGetReleasePlan() {
+  const cliMajor = getChangesetsCliMajor()
+  let pkg = RELEASE_PLAN_BY_CLI_MAJOR[cliMajor]
+  if (!pkg) {
+    console.warn(
+      `Unsupported @changesets/cli major v${cliMajor}, falling back to v${DEFAULT_CLI_MAJOR}`,
+    )
+    pkg = RELEASE_PLAN_BY_CLI_MAJOR[DEFAULT_CLI_MAJOR]
+  }
+  console.log(`Using ${pkg}`)
+  const { default: getReleasePlan } = await import(pkg)
+  return getReleasePlan
+}
+
 function reasonRank(reason) {
   return reason === 'Changeset' ? 2 : 1
 }
@@ -27,6 +68,7 @@ async function main() {
     allowPositionals: false,
   })
 
+  const getReleasePlan = await loadGetReleasePlan()
   const releasePlan = await getReleasePlan(GITHUB_WORKSPACE)
   const releases = releasePlan.releases