Fix an invariance type error in the MockedResponse type. (#12920)

Author: phryneas

.api-reports/api-report-testing.api.md

@@ -43,7 +43,9 @@ export namespace MockLink {
         variables?: TVariables | VariableMatcher<TVariables>;
     }
     // (undocumented)
-    export interface MockedResponse<out TData = Record<string, any>, out TVariables extends OperationVariables = Record<string, any>> {
+    export interface MockedResponse<
+    /** @ts-ignore */
+    out TData = Record<string, any>, out TVariables extends OperationVariables = Record<string, any>> {
         // (undocumented)
         delay?: number | MockLink.DelayFunction;
         // (undocumented)

.changeset/chilled-pillows-pull.md

@@ -0,0 +1,5 @@
+---
+"@apollo/client": patch
+---
+
+Fix an invariance type error in the `MockedResponse` type.

config/build.ts

@@ -5,13 +5,14 @@ import { $ } from "zx";
 
 import { babelTransform } from "./babel.ts";
 import { compileTs } from "./compileTs.ts";
-import { reactCompiler } from "./react-compiler.ts";
 import { deprecateInternals } from "./deprecateInternals.ts";
 import { addExports } from "./exports.ts";
 import { distDir } from "./helpers.ts";
 import { inlineInheritDoc } from "./inlineInheritDoc.ts";
 import { prepareDist } from "./prepareDist.ts";
+import { preserveTsIgnore } from "./preserveTsIgnore.ts";
 import { processInvariants } from "./processInvariants.ts";
+import { reactCompiler } from "./react-compiler.ts";
 import { verifySourceMaps } from "./verifySourceMaps.ts";
 import { updateVersion, verifyVersion } from "./version.ts";
 
@@ -42,6 +43,7 @@ const buildSteps = {
   updateVersion,
   inlineInheritDoc,
   deprecateInternals,
+  preserveTsIgnore,
   processInvariants,
   reactCompiler,
   verifyVersion,

config/preserveTsIgnore.ts

@@ -0,0 +1,50 @@
+/**
+ * TypeScript removes normal comments when it creates declaration files.
+ *
+ * That means that `// @ts-ignore` comments are removed, which can lead to
+ * unwanted errors in the generated declaration files, if those comments
+ * are still necessary in the generated `.d.ts` files.
+ *
+ * As a workaround, it's possible to use `/** @ts-ignore ...` instead,
+ * as these are preserved in the generated declaration files.
+ * The downside to this is that these comments then also might end up in
+ * IDE inline documentation, which we want to avoid.
+ *
+ * This build step post-processes all `.d.ts` files if a block-comment
+ * starts with `* @ts-ignore`, it removes the leading `*`, effectively
+ * turning them into non-docBlock comments for shipping.
+ */
+
+import { visit } from "recast";
+
+import type { BuildStep } from "./build.ts";
+import { applyRecast, frameComment } from "./helpers.ts";
+
+export const preserveTsIgnore: BuildStep = async (options) =>
+  applyRecast({
+    glob: `**/*.{${options.jsExt},d.${options.tsExt}}`,
+    cwd: options.targetDir,
+    transformStep({ ast }) {
+      return {
+        ast: visit(ast, {
+          visitNode(path) {
+            this.traverse(path);
+            const node = path.node;
+
+            if (!node.comments) {
+              return;
+            }
+
+            for (const comment of node.comments) {
+              if (
+                comment.type === "CommentBlock" &&
+                comment.value.match(/^\*\s*@ts-ignore/)
+              ) {
+                comment.value = comment.value.substring(1);
+              }
+            }
+          },
+        }),
+      };
+    },
+  });

src/testing/core/mocking/mockLink.ts

@@ -54,7 +54,7 @@ export declare namespace MockLink {
   }
 
   export interface MockedResponse<
-    // @ts-ignore
+    /** @ts-ignore */
     out TData = Record<string, any>,
     out TVariables extends OperationVariables = Record<string, any>,
   > {