install package with file: protocol as default if it exists in the filesystem

__tests__/commands/install/integration.js

@@ -272,6 +272,15 @@ test.concurrent('install file: protocol', (): Promise<void> => {
   });
 });
 
+test.concurrent('install with file: protocol as default', (): Promise<void> => {
+  return runInstall({noLockfile: true}, 'install-file-as-default', async (config) => {
+    assert.equal(
+      await fs.readFile(path.join(config.cwd, 'node_modules', 'foo', 'index.js')),
+      'foobar\n',
+    );
+  });
+});
+
 test.concurrent('install everything when flat is enabled', (): Promise<void> => {
   return runInstall({noLockfile: true, flat: true}, 'install-file', async (config) => {
     assert.equal(

__tests__/fixtures/install/install-file-as-default/bar/index.js

@@ -0,0 +1 @@
+foobar

__tests__/fixtures/install/install-file-as-default/bar/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "bar",
+  "version": "0.0.0",
+  "main": "index.js"
+}

__tests__/fixtures/install/install-file-as-default/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "foo": "bar"
+  }
+}

__tests__/fixtures/install/install-file-as-default/yarn.lock

@@ -0,0 +1,4 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+"foo@file:bar":
+  version "0.0.0"

src/package-request.js

@@ -14,7 +14,9 @@ import {entries} from './util/misc.js';
 import * as constants from './constants.js';
 import * as versionUtil from './util/version.js';
 import * as resolvers from './resolvers/index.js';
+import * as fs from './util/fs.js';
 
+const path = require('path');
 const invariant = require('invariant');
 const semver = require('semver');
 
@@ -98,7 +100,7 @@ export default class PackageRequest {
    */
 
   async findVersionOnRegistry(pattern: string): Promise<Manifest> {
-    const {range, name} = PackageRequest.normalizePattern(pattern);
+    const {range, name} = this.normalize(pattern);
 
     const exoticResolver = PackageRequest.getExoticResolver(range);
     if (exoticResolver) {
@@ -135,6 +137,30 @@ export default class PackageRequest {
     }
   }
 
+  /**
+   * If pattern:
+   * - contains : it will return because is something like '<protocol>:<something else' or an url
+   * - is a file it will prepend file:
+   * otherwise it will return
+   */
+  normalizeRange(pattern: string): string {
+    if (pattern.includes(':')) {
+      return pattern;
+    }
+
+    if (fs.existsSync(path.join(this.config.cwd, pattern))) {
+      return `file:${pattern}`;
+    }
+
+    return pattern;
+  }
+
+  normalize(pattern: string): any {
+    const {name, range, hasVersion} = PackageRequest.normalizePattern(pattern);
+    const new_range = this.normalizeRange(range);
+    return {name, range: new_range, hasVersion};
+  }
+
   /**
    * Explode and normalize a pattern into it's name and range.
    */
@@ -219,7 +245,7 @@ export default class PackageRequest {
 
     // check if while we were resolving this dep we've already resolved one that satisfies
     // the same range
-    const {range, name} = PackageRequest.normalizePattern(this.pattern);
+    const {range, name} = this.normalize(this.pattern);
     const resolved: ?Manifest = this.resolver.getHighestRangeVersionMatch(name, range);
     if (resolved) {
       this.reportResolvedRangeMatch(info, resolved);

src/util/fs.js

@@ -22,10 +22,11 @@ export const access: (path: string, mode?: number) => Promise<void> = promisify(
 export const stat: (path: string) => Promise<fs.Stats> = promisify(fs.stat);
 export const unlink: (path: string) => Promise<void> = promisify(require('rimraf'));
 export const mkdirp: (path: string) => Promise<void> = promisify(require('mkdirp'));
-export const exists: (path: string) => Promise<boolean>  = promisify(fs.exists, true);
+export const exists: (path: string) => Promise<boolean> = promisify(fs.exists, true);
 export const lstat: (path: string) => Promise<fs.Stats> = promisify(fs.lstat);
 export const chmod: (path: string, mode: number | string) => Promise<void> = promisify(fs.chmod);
 export const link: (path: string) => Promise<fs.Stats> = promisify(fs.link);
+export const existsSync: (path: string) => boolean = fs.existsSync;
 
 const CONCURRENT_QUEUE_ITEMS = 4;