From ae1b596e9b5dba2a448b53e38b3e70916a7fde95 Mon Sep 17 00:00:00 2001
From: zazido <franzhang@zhiwen.me>
Date: Tue, 1 Jan 2019 21:24:54 +0800
Subject: [PATCH] perf(core): do not deeply resolve an input type more than
 once (#373)

Relates to #310
---
 packages/graphqlgen/src/generators/common.spec.ts |  1 -
 packages/graphqlgen/src/generators/common.ts      | 15 ++++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/packages/graphqlgen/src/generators/common.spec.ts b/packages/graphqlgen/src/generators/common.spec.ts
index 27b3c2bd..50c76520 100644
--- a/packages/graphqlgen/src/generators/common.spec.ts
+++ b/packages/graphqlgen/src/generators/common.spec.ts
@@ -141,7 +141,6 @@ Array [
   "B",
   "D",
   "C",
-  "D",
 ]
 `)
 })
diff --git a/packages/graphqlgen/src/generators/common.ts b/packages/graphqlgen/src/generators/common.ts
index 7f11148e..ff81c94d 100644
--- a/packages/graphqlgen/src/generators/common.ts
+++ b/packages/graphqlgen/src/generators/common.ts
@@ -239,9 +239,18 @@ export function deepResolveInputTypes(
     const childTypes = type.fields
       .filter(t => t.type.isInput && !seen[t.type.name])
       .map(t => t.type.name)
-      .map(name =>
-        deepResolveInputTypes(inputTypesMap, name, { ...seen, [name]: true }),
-      )
+      .map(name => {
+        /**
+         * Mutate so that we track state across tree branches.
+         *
+         * Example, only visit "C" once:
+         *     A
+         *     ├── B ── C
+         *     └── D ── C
+         */
+        seen[name] = true
+        return deepResolveInputTypes(inputTypesMap, name, seen)
+      })
       .reduce(concat, [])
     return [typeName, ...childTypes]
   } else {