Relabel + clarify getPackageForModule, getClosestPackage, etc

Summary:
This is a simple relabelling to make clear when resolution-related methods expect *absolute* paths, as opposed to origin-relative, package-relative or bare specifiers that are present under the name `modulePath`. It should make the next diffs a little easier to reason about.

Changelog: Internal

Reviewed By: huntie

Differential Revision: D56788884

fbshipit-source-id: 5c6a3d5c2d7f11519325756a26529c4fa9238013

Author: robhogan

packages/metro-resolver/src/resolve.js

@@ -138,6 +138,8 @@ function resolve(
       return {type: 'empty'};
     }
 
+    // candidate should be absolute here - we assume that redirectModulePath
+    // always returns an absolute path when given an absolute path.
     const result = resolvePackage(context, candidate, platform);
     if (result.type === 'resolved') {
       return result.resolution;
@@ -252,11 +254,11 @@ function resolvePackage(
    * The absolute path to a file or directory that may be contained within an
    * npm package, e.g. from being joined with `context.extraNodeModules`.
    */
-  modulePath: string,
+  absoluteCandidatePath: string,
   platform: string | null,
 ): Result<Resolution, FileAndDirCandidates> {
   if (context.unstable_enablePackageExports) {
-    const pkg = context.getPackageForModule(modulePath);
+    const pkg = context.getPackageForModule(absoluteCandidatePath);
     const exportsField = pkg?.packageJson.exports;
 
     if (pkg != null && exportsField != null) {
@@ -276,7 +278,7 @@ function resolvePackage(
         const packageExportsResult = resolvePackageTargetFromExports(
           {...context, unstable_conditionNames: conditionNamesOverride},
           pkg.rootPath,
-          modulePath,
+          absoluteCandidatePath,
           exportsField,
           platform,
         );
@@ -302,7 +304,7 @@ function resolvePackage(
     }
   }
 
-  return resolveModulePath(context, modulePath, platform);
+  return resolveModulePath(context, absoluteCandidatePath, platform);
 }
 
 /**

packages/metro-resolver/src/types.js

@@ -121,12 +121,13 @@ export type ResolutionContext = $ReadOnly<{
   getPackage: (packageJsonPath: string) => ?PackageJson,
 
   /**
-   * Get the package information and parsed `package.json` file for for a given
-   * module path, if it is contained within an npm package.
+   * Get the closest package scope and parsed `package.json` for a given
+   * absolute candidate path (which need not exist), or null if there is no
+   * package.json closer than the nearest node_modules directory.
    *
    * @deprecated See https://github.com/facebook/metro/commit/29c77bff31e2475a086bc3f04073f485da8f9ff0
    */
-  getPackageForModule: (modulePath: string) => ?PackageInfo,
+  getPackageForModule: (absoluteModulePath: string) => ?PackageInfo,
 
   /**
    * The dependency descriptor, within the origin module, corresponding to the

packages/metro-resolver/types/types.d.ts

@@ -97,12 +97,15 @@ export interface ResolutionContext {
   readonly getPackage: (packageJsonPath: string) => PackageJson | null;
 
   /**
-   * Get the package information and parsed `package.json` file for for a given
-   * module path, if it is contained within an npm package.
+   * Get the closest package scope and parsed `package.json` for a given
+   * absolute candidate path (which need not exist), or null if there is no
+   * package.json closer than the nearest node_modules directory.
    *
-   * @deprecated
+   * @deprecated See https://github.com/facebook/metro/commit/29c77bff31e2475a086bc3f04073f485da8f9ff0
    */
-  readonly getPackageForModule: (modulePath: string) => PackageInfo | null;
+  readonly getPackageForModule: (
+    absoluteModulePath: string,
+  ) => PackageInfo | null;
 
   /**
    * The dependency descriptor, within the origin module, corresponding to the

packages/metro/src/node-haste/DependencyGraph.js

@@ -152,8 +152,8 @@ class DependencyGraph extends EventEmitter {
     return self;
   }
 
-  _getClosestPackage(filePath: string): ?string {
-    const parsedPath = path.parse(filePath);
+  _getClosestPackage(absoluteModulePath: string): ?string {
+    const parsedPath = path.parse(absoluteModulePath);
     const root = parsedPath.root;
     let dir = path.join(parsedPath.dir, parsedPath.base);
 
@@ -242,7 +242,8 @@ class DependencyGraph extends EventEmitter {
 
   _createModuleCache(): ModuleCache {
     return new ModuleCache({
-      getClosestPackage: filePath => this._getClosestPackage(filePath),
+      getClosestPackage: absoluteModulePath =>
+        this._getClosestPackage(absoluteModulePath),
     });
   }
 

packages/metro/src/node-haste/DependencyGraph/ModuleResolution.js

@@ -53,7 +53,7 @@ export type ModuleishCache<TPackage> = interface {
     platform?: string,
     supportsNativePlatform?: boolean,
   ): TPackage,
-  getPackageOf(modulePath: string): ?TPackage,
+  getPackageOf(absolutePath: string): ?TPackage,
 };
 
 type Options<TPackage> = $ReadOnly<{
@@ -179,8 +179,8 @@ class ModuleResolver<TPackage: Packageish> {
             resolveHastePackage: (name: string) =>
               this._options.getHastePackagePath(name, platform),
             getPackage: this._getPackage,
-            getPackageForModule: (modulePath: string) =>
-              this._getPackageForModule(fromModule, modulePath),
+            getPackageForModule: (absoluteModulePath: string) =>
+              this._getPackageForModule(absoluteModulePath),
           },
           dependency,
         ),
@@ -249,14 +249,11 @@ class ModuleResolver<TPackage: Packageish> {
     return null;
   };
 
-  _getPackageForModule = (
-    fromModule: Moduleish,
-    modulePath: string,
-  ): ?PackageInfo => {
+  _getPackageForModule = (absolutePath: string): ?PackageInfo => {
     let pkg;
 
     try {
-      pkg = this._options.moduleCache.getPackageOf(modulePath);
+      pkg = this._options.moduleCache.getPackageOf(absolutePath);
     } catch (e) {
       // Do nothing. The standard module cache does not trigger any error, but
       // the ModuleGraph one does, if the module does not exist.

packages/metro/src/node-haste/ModuleCache.js

@@ -14,7 +14,7 @@
 const Module = require('./Module');
 const Package = require('./Package');
 
-type GetClosestPackageFn = (filePath: string) => ?string;
+type GetClosestPackageFn = (absoluteFilePath: string) => ?string;
 
 class ModuleCache {
   _getClosestPackage: GetClosestPackageFn;
@@ -69,21 +69,22 @@ class ModuleCache {
     return this.getPackageOf(module.path);
   }
 
-  getPackageOf(modulePath: string): ?Package {
-    let packagePath: ?string = this._packagePathByModulePath[modulePath];
+  getPackageOf(absoluteModulePath: string): ?Package {
+    let packagePath: ?string =
+      this._packagePathByModulePath[absoluteModulePath];
     if (packagePath && this._packageCache[packagePath]) {
       return this._packageCache[packagePath];
     }
 
-    packagePath = this._getClosestPackage(modulePath);
+    packagePath = this._getClosestPackage(absoluteModulePath);
     if (!packagePath) {
       return null;
     }
 
-    this._packagePathByModulePath[modulePath] = packagePath;
+    this._packagePathByModulePath[absoluteModulePath] = packagePath;
     const modulePaths =
       this._modulePathsByPackagePath[packagePath] ?? new Set();
-    modulePaths.add(modulePath);
+    modulePaths.add(absoluteModulePath);
     this._modulePathsByPackagePath[packagePath] = modulePaths;
 
     return this.getPackage(packagePath);