Eval: Add sync-storybook-version harness + --skip-automigrations upgrade flag

code/lib/cli-storybook/src/bin/run.ts

@@ -171,6 +171,10 @@ command('upgrade')
   .option('-f --force', 'force the upgrade, skipping autoblockers')
   .option('-n --dry-run', 'Only check for upgrades, do not install')
   .option('-s --skip-check', 'Skip postinstall version and automigration checks')
+  .option(
+    '--skip-automigrations',
+    'Skip running automigrations entirely (only update package versions and install)'
+  )
   .option(
     '-c, --config-dir <dir-name...>',
     'Directory(ies) where to load Storybook configurations from'

code/lib/cli-storybook/src/upgrade.ts

@@ -116,6 +116,7 @@ export const checkVersionConsistency = () => {
 
 export type UpgradeOptions = {
   skipCheck: boolean;
+  skipAutomigrations?: boolean;
   packageManager?: PackageManagerName;
   dryRun: boolean;
   yes: boolean;
@@ -413,11 +414,17 @@ export async function upgrade(options: UpgradeOptions): Promise<void> {
       }
     }
 
-    // Run automigrations for all projects
-    const { automigrationResults, detectedAutomigrations } = await runAutomigrations(
-      storybookProjects,
-      options
-    );
+    // Run automigrations for all projects (unless explicitly skipped)
+    let automigrationResults: Record<string, AutomigrationResult> = {};
+    let detectedAutomigrations: AutomigrationCheckResult[] = [];
+    if (options.skipAutomigrations) {
+      logger.log('Skipping automigrations (--skip-automigrations).');
+    } else {
+      ({ automigrationResults, detectedAutomigrations } = await runAutomigrations(
+        storybookProjects,
+        options
+      ));
+    }
 
     // Install dependencies
     const rootPackageManager =

scripts/eval/README.md

@@ -111,6 +111,33 @@ node scripts/eval/sync-baselines.ts --skip-push
 
 The script ensures each repo is on its default branch with no local changes, fetches the latest from origin, replaces the `.storybook` directory with the canonical baseline, and commits/pushes if anything changed.
 
+## Syncing the Storybook version
+
+`sync-storybook-version.ts` bumps every benchmark repo to a specific Storybook version. It mirrors the shape of `sync-baselines.ts`: for each project it ensures the source clone is present and clean, checks out and fast-forwards the default branch, runs `npx storybook@<version> upgrade --yes --force --skip-check --skip-automigrations -c <projectDir>/.storybook` from the **repo root**, then commits and pushes any resulting changes. Running from the repo root (with `-c` pointing at the project's `.storybook` dir) lets the Storybook CLI discover the correct workspace `package.json` in pnpm/yarn monorepos where the Storybook deps live at the workspace root and the config lives in a sub-package.
+
+```sh
+# Upgrade every benchmark repo to a stable version
+node scripts/eval/sync-storybook-version.ts --version 9.1.0
+
+# Upgrade to a canary published from a Storybook PR
+node scripts/eval/sync-storybook-version.ts --version 0.0.0-pr-34297-sha-abcdef12
+
+# Upgrade a subset of projects
+node scripts/eval/sync-storybook-version.ts --version latest --project mealdrop --project edgy
+
+# Commit locally without pushing yet
+node scripts/eval/sync-storybook-version.ts --version 9.1.0 --skip-push
+```
+
+The upgrade passes the following flags:
+
+- `--yes` — auto-accepts prompts.
+- `--force` — skips the autoblocker gate (useful for canary or major-version bumps).
+- `--skip-check` — skips the postinstall self-check.
+- `--skip-automigrations` — prevents the CLI from rewriting source files (e.g. the `wrap-getAbsolutePath` migration).
+
+The commit message defaults to `Eval: upgrade Storybook to <version>`. If you review a `--skip-push` run first, rerun the same command without `--skip-push` to push the existing local upgrade commits. Run `sync-baselines.ts` afterwards if you also need to refresh the canonical `.storybook` config in every repo.
+
 ## Collecting results
 
 After running trials, `collect-pr-data.ts` scrapes the published draft PRs and loads the data into a local SQLite database.

scripts/eval/lib/utils.ts

@@ -20,6 +20,8 @@ export const EXAMPLE_PROMPT_BASENAME = 'pattern-copy-play';
 export const NODE_EVAL_TRIAL_SCRIPT = 'scripts/eval/eval.ts' as const;
 export const NODE_EVAL_RUN_BATCH_SCRIPT = 'scripts/eval/run-batch.ts' as const;
 export const NODE_EVAL_SYNC_BASELINES_SCRIPT = 'scripts/eval/sync-baselines.ts' as const;
+export const NODE_EVAL_SYNC_STORYBOOK_VERSION_SCRIPT =
+  'scripts/eval/sync-storybook-version.ts' as const;
 export const NODE_EVAL_COLLECT_PR_DATA_SCRIPT = 'scripts/eval/collect-pr-data.ts' as const;
 export const STORYBOOK_DIRNAME = '.storybook';
 export const EVAL_RESULTS_DIRNAME = 'eval-results';