Ignore non-resolvable keys in locally satisfiable key checking

.changeset/rich-tips-study.md

@@ -0,0 +1,6 @@
+---
+"@apollo/query-planner": patch
+"@apollo/query-graphs": patch
+---
+
+Ignore non-resolvable keys when adding a subgraph jump for `@requires`/`@fromContext`. 

query-graphs-js/src/graphPath.ts

@@ -1930,6 +1930,9 @@ export function getLocallySatisfiableKey(graph: QueryGraph, typeVertex: Vertex):
   assert(metadata, () => `Could not find federation metadata for source ${typeVertex.source}`);
   const keyDirective = metadata.keyDirective();
   for (const key of type.appliedDirectivesOf(keyDirective)) {
+    if (!(key.arguments().resolvable ?? true)) {
+      continue;
+    }
     const selection = parseFieldSetArgument({ parentType: type, directive: key });
     if (!metadata.selectionSelectsAnyExternalField(selection)) {
       return selection;

query-planner-js/src/__tests__/buildPlan.test.ts

@@ -2986,6 +2986,97 @@ describe('@requires', () => {
       }
     `);
   });
+
+  it('ignores non-resolvable keys when inserting self jump for @requires', () => {
+    const subgraph1 = {
+      name: 'A',
+      typeDefs: gql`
+        type Query {
+          t: T
+        }
+
+        type T @key(fields: "id1", resolvable: false) @key(fields: "id2 id3") {
+          id1: ID!
+          id2: ID!
+          id3: ID!
+          req: Int @external
+          v: Int @requires(fields: "req")
+        }
+      `,
+    };
+
+    const subgraph2 = {
+      name: 'B',
+      typeDefs: gql`
+        type T @key(fields: "id1") {
+          id1: ID!
+          req: Int
+        }
+      `,
+    };
+
+    const [api, queryPlanner] = composeAndCreatePlanner(subgraph1, subgraph2);
+    const operation = operationFromDocument(
+      api,
+      gql`
+        {
+          t {
+            v
+          }
+        }
+      `,
+    );
+
+    const plan = queryPlanner.buildQueryPlan(operation);
+    expect(plan).toMatchInlineSnapshot(`
+      QueryPlan {
+        Sequence {
+          Fetch(service: "A") {
+            {
+              t {
+                __typename
+                id1
+                id2
+                id3
+              }
+            }
+          },
+          Flatten(path: "t") {
+            Fetch(service: "B") {
+              {
+                ... on T {
+                  __typename
+                  id1
+                }
+              } =>
+              {
+                ... on T {
+                  req
+                }
+              }
+            },
+          },
+          Flatten(path: "t") {
+            Fetch(service: "A") {
+              {
+                ... on T {
+                  __typename
+                  req
+                  id2
+                  id3
+                }
+              } =>
+              {
+                ... on T {
+                  v
+                }
+              }
+            },
+          },
+        },
+      }
+    `);
+  });
 });
 
 describe('fetch operation names', () => {