From 747a3526a4b6327b81d8acf8b564e6fc06bdc114 Mon Sep 17 00:00:00 2001
From: Geoffroy Couprie <apollo@geoffroycouprie.com>
Date: Thu, 10 Aug 2023 09:40:39 +0200
Subject: [PATCH] self is immutable in the Plugin trait's methods (#3555)

Fix #3539
---
 .changesets/docs_geal_plugin_doc_fix.md |  4 ++++
 docs/source/customizations/native.mdx   | 10 +++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)
 create mode 100644 .changesets/docs_geal_plugin_doc_fix.md

diff --git a/.changesets/docs_geal_plugin_doc_fix.md b/.changesets/docs_geal_plugin_doc_fix.md
new file mode 100644
index 0000000000..46552bb5b6
--- /dev/null
+++ b/.changesets/docs_geal_plugin_doc_fix.md
@@ -0,0 +1,4 @@
+### self is immutable in the Plugin trait's methods ([Issue #3539](https://github.com/apollographql/router/issues/3539))
+
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/3555
\ No newline at end of file
diff --git a/docs/source/customizations/native.mdx b/docs/source/customizations/native.mdx
index 8b2ffacf0e..3ad95c7cb9 100644
--- a/docs/source/customizations/native.mdx
+++ b/docs/source/customizations/native.mdx
@@ -96,21 +96,21 @@ impl Plugin for HelloWorld {
     // Only define the hooks you need to modify. Each default hook
     // implementation returns its associated service with no changes.
     fn router_service(
-        &mut self,
+        &self,
         service: router::BoxService,
     ) -> router::BoxService {
         service
     }
 
     fn supergraph_service(
-        &mut self,
+        &self,
         service: router::BoxService,
     ) -> router::BoxService {
         service
     }
 
     fn execution_service(
-        &mut self,
+        &self,
         service: execution::BoxService,
     ) -> execution::BoxService {
         service
@@ -120,7 +120,7 @@ impl Plugin for HelloWorld {
     // being invoked. That's because this service might invoke *multiple*
     // subgraphs for a single request, and this is called once for each.
     fn subgraph_service(
-        &mut self,
+        &self,
         name: &str,
         service: subgraph::BoxService,
     ) -> subgraph::BoxService {
@@ -141,7 +141,7 @@ use tower::ServiceBuilderExt;
 use apollo_router::ServiceBuilderExt as ApolloServiceBuilderExt;
 
 fn supergraph_service(
-    &mut self,
+    &self,
     service: router::BoxService,
 ) -> router::BoxService {
     // Always use service builder to compose your plugins.