From 32dadefb537979ef7e981eff40dbb7756ee22049 Mon Sep 17 00:00:00 2001
From: Zoltan Kochan <z@kochan.io>
Date: Thu, 22 May 2025 15:26:51 +0200
Subject: [PATCH] fix: install exiting with 1 exit code and no error message
 (#9567)

close #9559
---
 .changeset/empty-files-laugh.md               |  6 ++++
 cli/default-reporter/src/reportError.ts       |  7 +++-
 .../src/install/reportPeerDependencyIssues.ts |  2 +-
 .../test/filterPeerDependencyIssues.test.ts   | 33 +++++++++++++++++++
 4 files changed, 46 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/empty-files-laugh.md

diff --git a/.changeset/empty-files-laugh.md b/.changeset/empty-files-laugh.md
new file mode 100644
index 0000000000..e3dccf00ac
--- /dev/null
+++ b/.changeset/empty-files-laugh.md
@@ -0,0 +1,6 @@
+---
+"@pnpm/core": patch
+"pnpm": patch
+---
+
+Installation should not exit with an error if `strictPeerDependencies` is `true` but all issues are ignored by `peerDependencyRules` [#9505](https://github.com/pnpm/pnpm/pull/9505).
diff --git a/cli/default-reporter/src/reportError.ts b/cli/default-reporter/src/reportError.ts
index 1714c5b95e..dd5c625a3c 100644
--- a/cli/default-reporter/src/reportError.ts
+++ b/cli/default-reporter/src/reportError.ts
@@ -444,7 +444,12 @@ function reportPeerDependencyIssuesError (
   strictPeerDependencies: false
 `)
   const rendered = renderPeerIssues(msg.issuesByProjects)
-  if (!rendered) return null
+  if (!rendered) {
+    // This should never happen.
+    return {
+      title: err.message,
+    }
+  }
   return {
     title: err.message,
     body: `${rendered}
diff --git a/pkg-manager/core/src/install/reportPeerDependencyIssues.ts b/pkg-manager/core/src/install/reportPeerDependencyIssues.ts
index 865fed0291..a8313fc67e 100644
--- a/pkg-manager/core/src/install/reportPeerDependencyIssues.ts
+++ b/pkg-manager/core/src/install/reportPeerDependencyIssues.ts
@@ -45,7 +45,7 @@ export function filterPeerDependencyIssues (
     newPeerDependencyIssuesByProjects[projectId] = { bad: {}, missing: {}, conflicts, intersections }
     for (const [peerName, issues] of Object.entries(missing)) {
       if (
-        ignoreMissingMatcher(peerName)
+        ignoreMissingMatcher(peerName) || issues.every(({ optional }) => optional)
       ) {
         continue
       }
diff --git a/pkg-manager/core/test/filterPeerDependencyIssues.test.ts b/pkg-manager/core/test/filterPeerDependencyIssues.test.ts
index 57c4eb55d9..ff711640f7 100644
--- a/pkg-manager/core/test/filterPeerDependencyIssues.test.ts
+++ b/pkg-manager/core/test/filterPeerDependencyIssues.test.ts
@@ -207,3 +207,36 @@ test('filterPeerDependencyIssues() allowed versions', () => {
     },
   })
 })
+
+test('filterPeerDependencyIssues() ignores missing optional dependency issues', () => {
+  expect(filterPeerDependencyIssues({
+    '.': {
+      missing: {
+        aaa: [
+          {
+            parents: [
+              {
+                name: 'xxx',
+                version: '1.0.0',
+              }],
+
+            optional: true,
+            wantedRange: '>=1.0.0 <3.0.0',
+          },
+        ],
+      },
+      bad: {},
+      conflicts: [],
+      intersections: {},
+    },
+  }, {
+    allowAny: [],
+  })).toStrictEqual({
+    '.': {
+      bad: {},
+      conflicts: [],
+      intersections: {},
+      missing: {},
+    },
+  })
+})