From f4fb77a09ea02b5f0a2676dd2c66a57f569ab168 Mon Sep 17 00:00:00 2001
From: Zoltan Kochan <z@kochan.io>
Date: Sat, 14 Nov 2026 12:54:43 +0100
Subject: [PATCH] fix: write YAML config files in block style

#85 switched the generated config files to JSON, which is valid YAML but
leaves pnpm-workspace.yaml as a multi-line flow collection. pnpm 12 edits
that file in place (`--allow-build` records `allowBuilds` there) and
refuses to edit a flow collection, so bootstrapping the installer failed
with ERR_PNPM_WORKSPACE_MANIFEST_WRITER_UNSUPPORTED_INLINE_BLOCK.

yamlText now serializes with js-yaml's dump, which still quotes and
escapes every value but emits block style. `noRefs` keeps shared objects
from becoming aliases, which pnpm cannot edit either.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 benchmarkFixture.js | 15 +++++++++++----
 package.json        |  1 +
 pnpm-lock.yaml      |  3 +++
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/benchmarkFixture.js b/benchmarkFixture.js
index 3c434b9..c6381d2 100644
--- a/benchmarkFixture.js
+++ b/benchmarkFixture.js
@@ -5,6 +5,7 @@ import { fileURLToPath } from 'node:url'
 
 import spawn from 'cross-spawn'
 import getFolderSize from 'get-folder-size'
+import YAML from 'js-yaml'
 import pathKey from 'path-key'
 import rimraf from 'rimraf'
 import tempy from 'tempy'
@@ -247,12 +248,18 @@ export function pnpmWorkspaceYaml (opts = {}) {
 }
 
 /**
- * Serializes a config file that is read as YAML. JSON is valid YAML, and
- * `JSON.stringify` quotes and escapes every value correctly, which
- * hand-written YAML does only for values that happen not to need it.
+ * Serializes a config file that is read as YAML. A serializer quotes and
+ * escapes every value correctly, which hand-written YAML does only for values
+ * that happen not to need it.
+ *
+ * The output must be block-style YAML, not JSON: pnpm edits
+ * `pnpm-workspace.yaml` in place (`--allow-build` records `allowBuilds`
+ * there), and it refuses to edit a document that is a multi-line flow
+ * collection. `noRefs` keeps shared objects from being written as aliases,
+ * which pnpm cannot edit either.
  */
 export function yamlText (value) {
-  return `${JSON.stringify(value, null, 2)}\n`
+  return YAML.dump(value, { noRefs: true })
 }
 
 /**
diff --git a/package.json b/package.json
index 0e1d5de..7600c78 100644
--- a/package.json
+++ b/package.json
@@ -20,6 +20,7 @@
     "dependencies": {
         "cross-spawn": "^7.0.3",
         "get-folder-size": "^3.1.0",
+        "js-yaml": "^4.3.2",
         "load-yaml-file": "^1.0.0",
         "path-key": "^4.0.0",
         "rimraf": "^4.0.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 4862936..f0f9d2e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -172,6 +172,9 @@ importers:
       get-folder-size:
         specifier: ^3.1.0
         version: 3.1.0
+      js-yaml:
+        specifier: ^4.3.2
+        version: 4.3.2
       load-yaml-file:
         specifier: ^1.0.0
         version: 1.0.0