From 0c4b52504029a91e22fa607a31dc2f9bf747a2e4 Mon Sep 17 00:00:00 2001
From: Banou <me@banou.dev>
Date: Tue, 8 Jun 2021 19:03:49 +0200
Subject: [PATCH 1/5] =?UTF-8?q?test:=20=E2=9C=85add=20`addTypePolicies`=20?=
 =?UTF-8?q?case?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/cache/inmemory/__tests__/policies.ts | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/cache/inmemory/__tests__/policies.ts b/src/cache/inmemory/__tests__/policies.ts
index beb5976d58a..4aef2a66b21 100644
--- a/src/cache/inmemory/__tests__/policies.ts
+++ b/src/cache/inmemory/__tests__/policies.ts
@@ -318,6 +318,29 @@ describe("type policies", function () {
     })).toBe("MotionPicture::3993d4118143");
   });
 
+  it.only("does not remove previous typePolicies", function () {
+    const cache = new InMemoryCache({
+      typePolicies: {
+        Query: {
+          fields: {
+            foo: () => 'foo'
+          }
+        },
+      },
+    });
+
+    cache.policies.addTypePolicies({
+      Query: {
+        fields: {
+          bar: () => 'bar'
+        }
+      },
+    });
+
+    expect(cache.readQuery({ query: gql` { foo } ` })).toEqual({foo: "foo"});
+    expect(cache.readQuery({ query: gql` { bar } ` })).toEqual({bar: "bar"});
+  });
+
   it("support inheritance", function () {
     const cache = new InMemoryCache({
       possibleTypes: {

From 2049e2e040f00dc063a5be8401276b299c2b7373 Mon Sep 17 00:00:00 2001
From: Banou <me@banou.dev>
Date: Tue, 8 Jun 2021 20:11:16 +0200
Subject: [PATCH 2/5] =?UTF-8?q?fix(cache):=20=F0=9F=90=9Bmerge=20policies?=
 =?UTF-8?q?=20instead=20of=20compacting=20them=20inside=20of=20getTypePoli?=
 =?UTF-8?q?cy?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/cache/inmemory/policies.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cache/inmemory/policies.ts b/src/cache/inmemory/policies.ts
index 76ffa0597cc..b9acff37dc9 100644
--- a/src/cache/inmemory/policies.ts
+++ b/src/cache/inmemory/policies.ts
@@ -21,7 +21,7 @@ import {
   isReference,
   getStoreKeyName,
   canUseWeakMap,
-  compact,
+  mergeDeep,
 } from '../../utilities';
 import { IdGetter, ReadMergeModifyContext, MergeInfo } from "./types";
 import {
@@ -545,7 +545,7 @@ export class Policies {
 
     const inbox = this.toBeAdded[typename];
     if (inbox && inbox.length) {
-      this.updateTypePolicy(typename, compact(...inbox.splice(0)));
+      this.updateTypePolicy(typename, mergeDeep(...inbox.splice(0)));
     }
 
     return this.typePolicies[typename];

From efbaf99c96caaecbe81d14b56d147dc0af56af3e Mon Sep 17 00:00:00 2001
From: Banou <me@banou.dev>
Date: Tue, 8 Jun 2021 20:12:09 +0200
Subject: [PATCH 3/5] =?UTF-8?q?test:=20=E2=9C=85remove=20`only`=20test=20f?=
 =?UTF-8?q?or=20the=20policies?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/cache/inmemory/__tests__/policies.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cache/inmemory/__tests__/policies.ts b/src/cache/inmemory/__tests__/policies.ts
index 4aef2a66b21..7787beee225 100644
--- a/src/cache/inmemory/__tests__/policies.ts
+++ b/src/cache/inmemory/__tests__/policies.ts
@@ -318,7 +318,7 @@ describe("type policies", function () {
     })).toBe("MotionPicture::3993d4118143");
   });
 
-  it.only("does not remove previous typePolicies", function () {
+  it("does not remove previous typePolicies", function () {
     const cache = new InMemoryCache({
       typePolicies: {
         Query: {

From 44367288269c01185fc2187e60ac3868163a112b Mon Sep 17 00:00:00 2001
From: Ben Newman <ben@apollographql.com>
Date: Tue, 8 Jun 2021 15:15:03 -0400
Subject: [PATCH 4/5] Call updateTypePolicy iteratively, rather than compacting
 policies.

---
 src/cache/inmemory/policies.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/cache/inmemory/policies.ts b/src/cache/inmemory/policies.ts
index b9acff37dc9..a7aca3a2f9d 100644
--- a/src/cache/inmemory/policies.ts
+++ b/src/cache/inmemory/policies.ts
@@ -21,7 +21,6 @@ import {
   isReference,
   getStoreKeyName,
   canUseWeakMap,
-  mergeDeep,
 } from '../../utilities';
 import { IdGetter, ReadMergeModifyContext, MergeInfo } from "./types";
 import {
@@ -545,7 +544,11 @@ export class Policies {
 
     const inbox = this.toBeAdded[typename];
     if (inbox && inbox.length) {
-      this.updateTypePolicy(typename, mergeDeep(...inbox.splice(0)));
+      // Merge the pending policies into this.typePolicies, in the order they
+      // were originally passed to addTypePolicy.
+      inbox.splice(0).forEach(policy => {
+        this.updateTypePolicy(typename, policy);
+      });
     }
 
     return this.typePolicies[typename];

From a009de18b7b7364d2493b37a6687394bfcb71e68 Mon Sep 17 00:00:00 2001
From: Ben Newman <ben@apollographql.com>
Date: Tue, 8 Jun 2021 15:21:31 -0400
Subject: [PATCH 5/5] Mention PR #8361 in CHANGELOG.md.

---
 CHANGELOG.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c7ae9f3bb10..319ae46c739 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## Apollo Client 3.3.20 (not yet released)
+
+### Bug fixes
+
+- Fix policy merging bug when calling `cache.policies.addTypePolicies` multiple times for the same type policy. <br/>
+  [@Banou26](https://github.com/Banou26) in [#8361](https://github.com/apollographql/apollo-client/pull/8361)
+
 ## Apollo Client 3.3.19
 
 ### Bug fixes