Improvements to new resolver

packages/core/core/src/Dependency.js

@@ -10,7 +10,12 @@ import type {
 } from '@parcel/types';
 import type {Dependency, Environment, Target} from './types';
 import {hashString} from '@parcel/hash';
-import {SpecifierType, Priority, BundleBehavior} from './types';
+import {
+  SpecifierType,
+  Priority,
+  BundleBehavior,
+  ExportsCondition,
+} from './types';
 
 import {toInternalSourceLocation} from './utils';
 import {toProjectPath} from './projectPath';
@@ -28,6 +33,7 @@ type DependencyOpts = {|
   isOptional?: boolean,
   loc?: SourceLocation,
   env: Environment,
+  packageConditions?: Array<string>,
   meta?: Meta,
   resolveFrom?: FilePath,
   range?: SemverRange,
@@ -53,15 +59,13 @@ export function createDependency(
         (opts.pipeline ?? '') +
         opts.specifierType +
         (opts.bundleBehavior ?? '') +
-        (opts.priority ?? 'sync'),
+        (opts.priority ?? 'sync') +
+        (opts.packageConditions ? JSON.stringify(opts.packageConditions) : ''),
     );
 
-  return {
-    ...opts,
-    resolveFrom: toProjectPath(projectRoot, opts.resolveFrom),
-    sourcePath: toProjectPath(projectRoot, opts.sourcePath),
+  let dep: Dependency = {
     id,
-    loc: toInternalSourceLocation(projectRoot, opts.loc),
+    specifier: opts.specifier,
     specifierType: SpecifierType[opts.specifierType],
     priority: Priority[opts.priority ?? 'sync'],
     needsStableName: opts.needsStableName ?? false,
@@ -70,7 +74,13 @@ export function createDependency(
       : null,
     isEntry: opts.isEntry ?? false,
     isOptional: opts.isOptional ?? false,
+    loc: toInternalSourceLocation(projectRoot, opts.loc),
+    env: opts.env,
     meta: opts.meta || {},
+    target: opts.target,
+    sourceAssetId: opts.sourceAssetId,
+    sourcePath: toProjectPath(projectRoot, opts.sourcePath),
+    resolveFrom: toProjectPath(projectRoot, opts.resolveFrom),
     range: opts.range,
     symbols:
       opts.symbols &&
@@ -85,7 +95,14 @@ export function createDependency(
           },
         ]),
       ),
+    pipeline: opts.pipeline,
   };
+
+  if (opts.packageConditions) {
+    convertConditions(opts.packageConditions, dep);
+  }
+
+  return dep;
 }
 
 export function mergeDependencies(a: Dependency, b: Dependency): void {
@@ -101,3 +118,25 @@ export function mergeDependencies(a: Dependency, b: Dependency): void {
   if (isEntry) a.isEntry = true;
   if (!isOptional) a.isOptional = false;
 }
+
+function convertConditions(conditions: Array<string>, dep: Dependency) {
+  // Store common package conditions as bit flags to reduce size.
+  // Custom conditions are stored as strings.
+  let packageConditions = 0;
+  let customConditions = [];
+  for (let condition of conditions) {
+    if (ExportsCondition[condition]) {
+      packageConditions |= ExportsCondition[condition];
+    } else {
+      customConditions.push(condition);
+    }
+  }
+
+  if (packageConditions) {
+    dep.packageConditions = packageConditions;
+  }
+
+  if (customConditions.length) {
+    dep.customPackageConditions = customConditions;
+  }
+}

packages/core/core/src/Transformation.js

@@ -6,6 +6,7 @@ import type {
   Transformer,
   TransformerResult,
   PackageName,
+  ResolveOptions,
   SemverRange,
 } from '@parcel/types';
 import type {WorkerApi} from '@parcel/workers';
@@ -734,12 +735,17 @@ export default class Transformation {
   ): Promise<$ReadOnlyArray<TransformerResult | UncommittedAsset>> {
     const logger = new PluginLogger({origin: transformerName});
 
-    const resolve = async (from: FilePath, to: string): Promise<FilePath> => {
+    const resolve = async (
+      from: FilePath,
+      to: string,
+      options?: ResolveOptions,
+    ): Promise<FilePath> => {
       let result = await pipeline.resolverRunner.resolve(
         createDependency(this.options.projectRoot, {
           env: asset.value.env,
           specifier: to,
-          specifierType: 'esm', // ???
+          specifierType: options?.specifierType || 'esm',
+          packageConditions: options?.packageConditions,
           sourcePath: from,
         }),
       );

packages/core/core/src/public/Dependency.js

@@ -17,7 +17,11 @@ import nullthrows from 'nullthrows';
 import Environment from './Environment';
 import Target from './Target';
 import {MutableDependencySymbols} from './Symbols';
-import {SpecifierType as SpecifierTypeMap, Priority} from '../types';
+import {
+  SpecifierType as SpecifierTypeMap,
+  Priority,
+  ExportsCondition,
+} from '../types';
 import {fromProjectPath} from '../projectPath';
 import {fromInternalSourceLocation} from '../utils';
 
@@ -101,6 +105,23 @@ export default class Dependency implements IDependency {
     return new Environment(this.#dep.env, this.#options);
   }
 
+  get packageConditions(): ?Array<string> {
+    // Merge custom conditions with conditions stored as bitflags.
+    // Order is not important because exports conditions are resolved
+    // in the order they are declared in the package.json.
+    let conditions = this.#dep.customPackageConditions;
+    if (this.#dep.packageConditions) {
+      conditions = conditions ? [...conditions] : [];
+      for (let key in ExportsCondition) {
+        if (this.#dep.packageConditions & ExportsCondition[key]) {
+          conditions.push(key);
+        }
+      }
+    }
+
+    return conditions;
+  }
+
   get meta(): Meta {
     return this.#dep.meta;
   }

packages/core/core/src/types.js

@@ -113,6 +113,17 @@ export const Priority = {
   lazy: 2,
 };
 
+// Must match package_json.rs in node-resolver-rs.
+export const ExportsCondition = {
+  import: 1 << 0,
+  require: 1 << 1,
+  module: 1 << 2,
+  style: 1 << 12,
+  sass: 1 << 13,
+  less: 1 << 14,
+  stylus: 1 << 15,
+};
+
 export type Dependency = {|
   id: string,
   specifier: DependencySpecifier,
@@ -124,6 +135,8 @@ export type Dependency = {|
   isOptional: boolean,
   loc: ?InternalSourceLocation,
   env: Environment,
+  packageConditions?: number,
+  customPackageConditions?: Array<string>,
   meta: Meta,
   resolverMeta?: ?Meta,
   target: ?Target,

packages/core/integration-tests/test/css.js

@@ -459,6 +459,19 @@ describe('css', () => {
     ]);
   });
 
+  it('should support the style package exports condition', async () => {
+    let b = await bundle(
+      path.join(__dirname, '/integration/css-exports/index.css'),
+    );
+
+    assertBundles(b, [
+      {
+        name: 'index.css',
+        assets: ['index.css', 'foo.css'],
+      },
+    ]);
+  });
+
   it('should support external CSS imports', async () => {
     let b = await bundle(
       path.join(__dirname, '/integration/css-external/a.css'),

packages/core/integration-tests/test/integration/css-exports/index.css

@@ -0,0 +1 @@
+@import 'npm:foo';

packages/core/integration-tests/test/integration/less-exports/index.less

@@ -0,0 +1 @@
+@import "foo";

packages/core/integration-tests/test/integration/sass-exports/index.sass

@@ -0,0 +1 @@
+@import "library"

packages/core/integration-tests/test/integration/sass-exports/package.json

@@ -0,0 +1,3 @@
+{
+  "private": true
+}

packages/core/integration-tests/test/integration/stylus-exports/index.styl

@@ -0,0 +1 @@
+@import "foo";

packages/core/integration-tests/test/less.js

@@ -285,4 +285,11 @@ describe('less', function () {
       ),
     );
   });
+
+  it('should support the less package exports condition', async function () {
+    await bundle(path.join(__dirname, '/integration/less-exports/index.less'));
+
+    let css = await outputFS.readFile(path.join(distDir, 'index.css'), 'utf8');
+    assert(css.includes('.a'));
+  });
 });

packages/core/integration-tests/test/sass.js

@@ -269,4 +269,20 @@ describe('sass', function () {
     let css = await outputFS.readFile(path.join(distDir, 'index.css'), 'utf8');
     assert(css.includes('.included'));
   });
+
+  it('should support package.json exports', async function () {
+    let b = await bundle(
+      path.join(__dirname, '/integration/sass-exports/index.sass'),
+    );
+
+    assertBundles(b, [
+      {
+        name: 'index.css',
+        assets: ['index.sass'],
+      },
+    ]);
+
+    let css = await outputFS.readFile(path.join(distDir, 'index.css'), 'utf8');
+    assert(css.includes('.external'));
+  });
 });

packages/core/integration-tests/test/stylus.js

@@ -172,4 +172,13 @@ describe('stylus', function () {
     assert(css.includes('.foo'));
     assert(css.includes('.bar'));
   });
+
+  it('should support the stylus package exports condition', async function () {
+    await bundle(
+      path.join(__dirname, '/integration/stylus-exports/index.styl'),
+    );
+
+    let css = await outputFS.readFile(path.join(distDir, 'index.css'), 'utf8');
+    assert(css.includes('.a'));
+  });
 });

packages/core/types/index.js

@@ -517,6 +517,13 @@ export type DependencyOptions = {|
   +loc?: SourceLocation,
   /** The environment of the dependency. */
   +env?: EnvironmentOptions,
+  /**
+   * A list of custom conditions to use when resolving package.json "exports" and "imports".
+   * This is combined with the conditions from the environment. However, it overrides the
+   * default "import" and "require" conditions inferred from the specifierType. To include those
+   * in addition to custom conditions, explicitly add them to this list.
+   */
+  +packageConditions?: Array<string>,
   /** Plugin-specific metadata for the dependency. */
   +meta?: Meta,
   /** The pipeline defined in .parcelrc that the dependency should be processed with. */
@@ -589,6 +596,13 @@ export interface Dependency {
   +loc: ?SourceLocation;
   /** The environment of the dependency. */
   +env: Environment;
+  /**
+   * A list of custom conditions to use when resolving package.json "exports" and "imports".
+   * This is combined with the conditions from the environment. However, it overrides the
+   * default "import" and "require" conditions inferred from the specifierType. To include those
+   * in addition to custom conditions, explicitly add them to this list.
+   */
+  +packageConditions: ?Array<string>;
   /** Plugin-specific metadata for the dependency. */
   +meta: Meta;
   /** If this is an entry, this is the target that is associated with that entry. */
@@ -959,7 +973,27 @@ export interface PluginLogger {
 /**
  * @section transformer
  */
-export type ResolveFn = (from: FilePath, to: string) => Promise<FilePath>;
+export type ResolveOptions = {|
+  /**
+   * How the specifier should be interpreted.
+   *   - esm: An ES module specifier. It is parsed as a URL, but bare specifiers are treated as node_modules.
+   *   - commonjs: A CommonJS specifier. It is not parsed as a URL.
+   *   - url: A URL that works as in a browser. Bare specifiers are treated as relative URLs.
+   *   - custom: A custom specifier. Must be handled by a custom resolver plugin.
+   */
+  +specifierType?: SpecifierType,
+  /** A list of custom conditions to use when resolving package.json "exports" and "imports". */
+  +packageConditions?: Array<string>,
+|};
+
+/**
+ * @section transformer
+ */
+export type ResolveFn = (
+  from: FilePath,
+  to: string,
+  options?: ResolveOptions,
+) => Promise<FilePath>;
 
 /**
  * @section validator

packages/resolvers/default/src/DefaultResolver.js

@@ -31,6 +31,7 @@ export default (new Resolver({
       env: dependency.env,
       sourcePath: dependency.sourcePath,
       loc: dependency.loc,
+      packageConditions: dependency.packageConditions,
     });
   },
 }): Resolver);