feat: compose tree-shaking source maps

Author: radist2s

packages/tree-shaking-plugin/package.json

@@ -73,6 +73,7 @@
     }
   },
   "devDependencies": {
+    "@jridgewell/trace-mapping": "^0.3.31",
     "@openapi-qraft/eslint-config": "workspace:*",
     "@openapi-qraft/rollup-config": "workspace:*",
     "@qraft/test-utils": "workspace:*",

packages/tree-shaking-plugin/src/core.test.ts

@@ -2,6 +2,8 @@ import '@qraft/test-utils/vitestFsMock';
 import fs from 'node:fs/promises';
 import os from 'node:os';
 import path from 'node:path';
+import { TraceMap, originalPositionFor } from '@jridgewell/trace-mapping';
+import type { SourceMapInput } from '@jridgewell/trace-mapping';
 import { describe, expect, it } from 'vitest';
 import { transformQraftTreeShaking as transformQraftTreeShakingImpl } from './core.js';
 import { createTransformPlan } from './lib/transform/plan.js';
@@ -59,11 +61,29 @@ export const createAPIClientOptions = () => ({
 `;
 
 type TransformOptions = Parameters<typeof transformQraftTreeShakingImpl>[2];
+type TransformWithInputSourceMap = (
+  code: string,
+  id: string,
+  options: TransformOptions,
+  resolver: Parameters<typeof transformQraftTreeShakingImpl>[3],
+  inputSourceMap?: SourceMapInput
+) => ReturnType<typeof transformQraftTreeShakingImpl>;
+
+const transformQraftTreeShakingImplWithInputSourceMap = transformQraftTreeShakingImpl satisfies (
+  code: string,
+  id: string,
+  options: TransformOptions,
+  resolver: Parameters<typeof transformQraftTreeShakingImpl>[3]
+) => ReturnType<typeof transformQraftTreeShakingImpl>;
+
+const transformQraftTreeShakingWithInputSourceMap =
+  transformQraftTreeShakingImplWithInputSourceMap as unknown as TransformWithInputSourceMap;
 
 async function transformQraftTreeShaking(
   code: string,
   id: string,
-  options: TransformOptions
+  options: TransformOptions,
+  inputSourceMap?: SourceMapInput
 ) {
   const fixtureRoot = path.dirname(path.dirname(id));
   const fixtureResolver = createFixtureResolver(fixtureRoot);
@@ -80,7 +100,13 @@ async function transformQraftTreeShaking(
     return fixtureResolver(specifier, importer);
   };
 
-  return transformQraftTreeShakingImpl(code, id, options, resolver);
+  return transformQraftTreeShakingWithInputSourceMap(
+    code,
+    id,
+    options,
+    resolver,
+    inputSourceMap
+  );
 }
 
 describe('transformQraftTreeShaking', () => {
@@ -141,6 +167,62 @@ export function App() {
       `);
   });
 
+  it('keeps a rewritten user call site traceable through an incoming source map', async () => {
+    const fixture = await createFixture();
+    const generatedSourceFile = path.join(fixture, 'src/App.generated.tsx');
+    const originalSourceFile = path.join(fixture, 'src/App.tsx');
+    const code = [
+      "import { createAPIClient } from './api';",
+      '',
+      'const api = createAPIClient();',
+      '',
+      'export function App() {',
+      '  return api.pets.getPets.useQuery();',
+      '}',
+    ].join('\n');
+    const inputSourceMap = createIdentitySourceMap(
+      generatedSourceFile,
+      originalSourceFile,
+      code
+    );
+
+    const result = await transformQraftTreeShaking(
+      code,
+      generatedSourceFile,
+      { createAPIClientFn: [{ name: 'createAPIClient', module: './api' }] },
+      inputSourceMap
+    );
+
+    if (!result) {
+      throw new Error('Expected transform result');
+    }
+
+    const generatedLineIndex = result.code
+      .split('\n')
+      .findIndex((line) => line.includes('api_pets_getPets.useQuery()'));
+
+    if (generatedLineIndex === -1) {
+      throw new Error('Expected rewritten user call site in generated output');
+    }
+
+    const generatedLine = generatedLineIndex + 1;
+    const generatedColumn = result.code
+      .split('\n')
+      [generatedLineIndex].indexOf('api_pets_getPets');
+
+    const traceMapInput = result.map! as SourceMapInput;
+
+    const position = originalPositionFor(new TraceMap(traceMapInput), {
+      line: generatedLine,
+      column: generatedColumn,
+    });
+
+    expect(position).toMatchObject({
+      source: originalSourceFile,
+      line: 6,
+    });
+  });
+
   it('aliases an imported operation when a local binding uses the same name', async () => {
     const fixture = await createFixture();
     const sourceFile = path.join(fixture, 'src/App.tsx');
@@ -1582,6 +1664,26 @@ function createFixtureResolver(fixtureRoot: string) {
   };
 }
 
+function createIdentitySourceMap(
+  generatedSourceFile: string,
+  originalSourceFile: string,
+  source: string
+): SourceMapInput {
+  const lineCount = source.split('\n').length;
+  const mappings = Array.from({ length: lineCount }, (_, index) =>
+    index === 0 ? 'AAAA' : 'AACA'
+  ).join(';');
+
+  return {
+    version: 3,
+    file: generatedSourceFile,
+    names: [],
+    sources: [originalSourceFile],
+    sourcesContent: [source],
+    mappings,
+  };
+}
+
 async function resolveFixtureModule(baseDir: string, importPath: string) {
   const base = path.resolve(baseDir, importPath);
   const candidateBases = new Set([base]);

packages/tree-shaking-plugin/src/core.ts

@@ -1,3 +1,6 @@
+import type { GeneratorOptions as BabelGeneratorOptions } from '@babel/generator';
+// eslint-disable-next-line import-x/no-extraneous-dependencies
+import type { SourceMapInput } from '@jridgewell/trace-mapping';
 import type { QraftResolver } from './lib/resolvers/common.js';
 import * as generateModule from '@babel/generator';
 import { createAgnosticResolver } from './lib/resolvers/agnostic.js';
@@ -34,14 +37,18 @@ export type QraftTreeShakeOptions = {
 };
 
 type GenerateFn = (typeof import('@babel/generator'))['default'];
+type GeneratorOptions = Omit<BabelGeneratorOptions, 'inputSourceMap'> & {
+  inputSourceMap?: SourceMapInput;
+};
 
 const generate = resolveDefaultExport<GenerateFn>(generateModule);
 
 export async function transformQraftTreeShaking(
   code: string,
   id: string,
   options: QraftTreeShakeOptions,
-  resolver: QraftResolver = createAgnosticResolver(options.resolve)
+  resolver: QraftResolver = createAgnosticResolver(options.resolve),
+  inputSourceMap?: SourceMapInput
 ) {
   if (!shouldTransformId(id, options)) return null;
 
@@ -56,11 +63,14 @@ export async function transformQraftTreeShaking(
 
   applyTransformPlan(plan, plan.runtimeLocalNames);
 
-  const result = generate(plan.ast, {
+  const generatorOptions = {
     sourceMaps: true,
     sourceFileName: id,
     jsescOption: { minimal: true },
-  });
+    inputSourceMap,
+  } satisfies GeneratorOptions;
+
+  const result = generate(plan.ast, generatorOptions);
 
   return {
     code: result.code,

packages/tree-shaking-plugin/src/lib/plugin/create-qraft-tree-shake-plugin.ts

@@ -23,7 +23,13 @@ export function createQraftTreeShakePlugin<TRuntimeContext = unknown>(
       },
       handler(this: any, code, id) {
         const resolver = createResolver(this, options.resolve);
-        return transformQraftTreeShaking(code, id, options, resolver);
+        return transformQraftTreeShaking(
+          code,
+          id,
+          options,
+          resolver,
+          this.inputSourceMap
+        );
       },
     },
   });

yarn.lock

@@ -4484,6 +4484,7 @@ __metadata:
     "@babel/parser": "npm:^7.29.0"
     "@babel/traverse": "npm:^7.29.0"
     "@babel/types": "npm:^7.29.0"
+    "@jridgewell/trace-mapping": "npm:^0.3.31"
     "@openapi-qraft/eslint-config": "workspace:*"
     "@openapi-qraft/rollup-config": "workspace:*"
     "@rspack/resolver": "npm:^0.4.0"