From c5ad309f4fdfc632a916ab11ecb243c2f855711d Mon Sep 17 00:00:00 2001
From: Michele Mancioppi <michele.mancioppi@dash0.com>
Date: Wed, 8 Jul 2026 13:36:42 +0200
Subject: [PATCH] fix: resolve pnpm version from action's package.json via
 node, not package_json_file

Same class of bug as #2 (Node version): `pnpm/action-setup`'s
`package_json_file` input is resolved relative to `$GITHUB_WORKSPACE`.
Passing an absolute path from `github.action_path` produces a
non-existent file; the action silently falls back to the caller's
package.json (which does not declare `packageManager`) and fails with:

  Error: No pnpm version is specified.
  Please specify it by one of the following ways:
    - in the GitHub Action config with the key "version"
    - in the package.json with the key "packageManager"
    - in the package.json with the key "devEngines.packageManager"

Caught by the second e2e run against dash0hq/sync-docs-e2e-source
(after PR #2 fixed the analogous node-version-file resolution).

Fix: read the version from the action's package.json in a preceding
bash step (Node is on PATH since setup-node just ran) and pass the
literal version string to setup-pnpm via `version`. Consistent with
the pattern PR #2 established for the Node version.

Local verification: pnpm lint, format:check, typecheck, and the 87
engine tests + docs-invariants scaffold test all green.
---
 action.yml | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/action.yml b/action.yml
index ee92cec..5615621 100644
--- a/action.yml
+++ b/action.yml
@@ -80,12 +80,23 @@ runs:
       with:
         node-version: ${{ steps.node-version.outputs.version }}
 
+    - name: Read required pnpm version from the action's package.json
+      id: pnpm-version
+      shell: bash
+      # `pnpm/action-setup`'s `package_json_file` input has the same resolution quirk as
+      # `actions/setup-node`'s `node-version-file`: absolute paths derived from `github.action_path`
+      # get concatenated with `$GITHUB_WORKSPACE` and the file is not found, at which point the
+      # action silently falls back to the caller's package.json (which does not declare a
+      # `packageManager` field) and fails with "No pnpm version is specified". Read the value here
+      # and pass it as a literal `version` instead. Node is on PATH because setup-node just ran.
+      run: |
+        version=$(node -p "require('${GITHUB_ACTION_PATH}/package.json').packageManager.replace('pnpm@', '')")
+        echo "version=$version" >> "$GITHUB_OUTPUT"
+
     - name: set up pnpm
       uses: pnpm/action-setup@8912a9102ac27614460f54aedde9e1e7f9aec20d # v6.0.5
       with:
-        # The action stores its own package manager version in package.json; use it here so pnpm and
-        # setup-node agree on the layout of node_modules.
-        package_json_file: ${{ github.action_path }}/package.json
+        version: ${{ steps.pnpm-version.outputs.version }}
         run_install: false
 
     - name: install action dependencies