From 357f136fc714ad8d0a5237d0e059f86f71c3173e Mon Sep 17 00:00:00 2001
From: Chris Lenfest <clenfest@apollographql.com>
Date: Mon, 16 Sep 2024 10:53:26 -0500
Subject: [PATCH] Revert #3142

---
 .changeset/slow-cups-exist.md                 |  5 ---
 .../src/__tests__/compose.external.test.ts    | 34 +------------------
 composition-js/src/merging/merge.ts           |  4 +--
 3 files changed, 2 insertions(+), 41 deletions(-)
 delete mode 100644 .changeset/slow-cups-exist.md

diff --git a/.changeset/slow-cups-exist.md b/.changeset/slow-cups-exist.md
deleted file mode 100644
index 994f3caa0..000000000
--- a/.changeset/slow-cups-exist.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"@apollo/composition": patch
----
-
-Relax error for detecting whether `@external` field matches. If the external field has extra optional parameters, allow it to pass composition as being able to pass the parameter is not necessary for a required field.
diff --git a/composition-js/src/__tests__/compose.external.test.ts b/composition-js/src/__tests__/compose.external.test.ts
index 00a661e4d..a2b62795c 100644
--- a/composition-js/src/__tests__/compose.external.test.ts
+++ b/composition-js/src/__tests__/compose.external.test.ts
@@ -62,7 +62,7 @@ describe('tests related to @external', () => {
       typeDefs: gql`
         type T @key(fields: "id") {
           id: ID!
-          f(x: Int!): String @shareable
+          f(x: Int): String @shareable
         }
       `,
     };
@@ -73,38 +73,6 @@ describe('tests related to @external', () => {
       ['EXTERNAL_ARGUMENT_MISSING', 'Field "T.f" is missing argument "T.f(x:)" in some subgraphs where it is marked @external: argument "T.f(x:)" is declared in subgraph "subgraphB" but not in subgraph "subgraphA" (where "T.f" is @external).'],
     ]);
   });
-  
-  it('succeeds on @external definition where difference between definitions is an optional argument', () => {
-    const subgraphA = {
-      name: 'subgraphA',
-      typeDefs: gql`
-        type Query {
-          locations: [Location]
-        }
-
-        type Location @key(fields: "id") {
-            id: ID!
-            name: String!
-            photo(smallVersion: Boolean): String! # New optional arg shouldn't break existing clients
-        }
-      `,
-    };
-
-    const subgraphB = {
-      name: 'subgraphB',
-      typeDefs: gql`
-        type Location @key(fields: "id") {
-            id: ID!
-            photo: String! @external
-            banner: String @requires(fields: "photo")
-        }
-      `,
-    };
-
-    const result = composeAsFed2Subgraphs([subgraphA, subgraphB]);
-    assertCompositionSuccess(result);
-  });
-
 
   it('errors on incompatible argument types in @external declaration', () => {
     const subgraphA = {
diff --git a/composition-js/src/merging/merge.ts b/composition-js/src/merging/merge.ts
index 722e04075..01b3430dd 100644
--- a/composition-js/src/merging/merge.ts
+++ b/composition-js/src/merging/merge.ts
@@ -1864,9 +1864,7 @@ class Merger {
         const name = destArg.name;
         const arg = source.argument(name);
         if (!arg) {
-          if (!destArg.type || destArg.type.kind === 'NonNullType') {
-            invalidArgsPresence.add(name);
-          }
+          invalidArgsPresence.add(name);
           continue;
         }
         if (!sameType(destArg.type!, arg.type!) && !this.isStrictSubtype(arg.type!, destArg.type!)) {