From a3d4df1f902f476f9635b0a8379cfbfe913dee1f Mon Sep 17 00:00:00 2001
From: James Ide <ide@expo.dev>
Date: Fri, 11 Feb 2022 17:31:30 -0800
Subject: [PATCH] [types] Make Knex's default generic parameter types be
 assignable to knex's

The default generic parameters of `Knex` didn't match the generic parameter types of `knex`. This becomes relevant with TypeScript 4.6 for `k: Knex = knex()` to work.

We can't change `knex`'s declaration from `TResult = unknown[]` to `TResult = Record<string, any>[]` because other types like `DeferredKeySelection.ReplaceBase` specifically look for `unknown`. Instead, this commit changes `Knex` to use `TResult = any[]`.

This works with TypeScript 4.6. Added both tsd and dtslint tests (tsd doesn't support TS 4.6 yet). Also tested this change in a larger codebase and confirmed that nearly all TS 4.6 errors were addressed.
---
 test-tsd/types.test-d.ts | 12 ++++++++++++
 types/index.d.ts         |  2 +-
 types/test.ts            |  3 +++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/test-tsd/types.test-d.ts b/test-tsd/types.test-d.ts
index 0732e6ffbd..6e639c6d08 100644
--- a/test-tsd/types.test-d.ts
+++ b/test-tsd/types.test-d.ts
@@ -19,6 +19,18 @@ expectType<Knex<any, unknown[]>>(knexCjsImport.knex({}));
 expectType<KnexTimeoutError>(new knex.KnexTimeoutError());
 expectType<KnexTimeoutError>(new knex.KnexTimeoutError());
 
+// Knex instances need to be assigned first so their generic types aren't inferred
+const k1 = knex({});
+expectAssignable<Knex>(k1);
+const k2 = knexStar.default({});
+expectAssignable<Knex>(k2);
+const k3 = knexStar.knex({});
+expectAssignable<Knex>(k3);
+const k4 = knexCjsImport.default({});
+expectAssignable<Knex>(k4);
+const k5 = knexCjsImport.knex({});
+expectAssignable<Knex>(k5);
+
 // eslint-disable-next-line
 expectType<any>(knexCjs({}));
 // eslint-disable-next-line
diff --git a/types/index.d.ts b/types/index.d.ts
index daccda0ccf..c4a8d8e02a 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -328,7 +328,7 @@ interface DMLOptions {
   includeTriggerModifications?: boolean;
 }
 
-export interface Knex<TRecord extends {} = any, TResult = Record<string, any>[]>
+export interface Knex<TRecord extends {} = any, TResult = any[]>
   extends Knex.QueryInterface<TRecord, TResult>, events.EventEmitter {
   <TTable extends Knex.TableNames>(
     tableName: TTable,
diff --git a/types/test.ts b/types/test.ts
index 9b086b9e03..553c8589c8 100644
--- a/types/test.ts
+++ b/types/test.ts
@@ -82,6 +82,9 @@ type _T8 = ExtendsWitness<Knex.QueryBuilder<User, number[]>, Knex.QueryBuilder>;
 type _T9 = ExtendsWitness<Knex.QueryBuilder<any, any[]>, Knex.QueryBuilder>;
 type _T10 = ExtendsWitness<Knex.QueryBuilder<User, number>, Knex.QueryBuilder>;
 
+// Ensure the return type of knex() is compatible with Knex with default parameters
+type _T2_1 = ExtendsWitness<typeof knexInstance, Knex>;
+
 declare module './tables' {
   interface Tables {
     users_inferred: User;