fixes yarnpkg#3506

__tests__/commands/add.js

@@ -819,3 +819,15 @@ test.concurrent('should retain build artifacts after add', (): Promise<void> =>
     'retain-build-artifacts-after-add',
   );
 });
+
+test.concurrent('installing with --pure-lockfile and then adding should keep build artifacts', (): Promise<void> => {
+  const fixture = 'integrity-pure-lockfile';
+
+  return runInstall({pureLockfile: true}, path.join('..', 'add', fixture), async (config, reporter): Promise<void> => {
+    expect(await fs.exists(path.join(config.cwd, 'node_modules', '.yarn-integrity'))).toBe(true);
+    expect(await fs.exists(path.join(config.cwd, 'node_modules', 'package-a', 'temp.txt'))).toBe(true);
+    const add = new Add(['[email protected]'], {}, config, reporter, (await Lockfile.fromDirectory(config.cwd)));
+    await add.init();
+    expect(await fs.exists(path.join(config.cwd, 'node_modules', 'package-a', 'temp.txt'))).toBe(true);
+  });
+});

__tests__/fixtures/add/integrity-pure-lockfile/package-a/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "package-a",
+  "version": "1.0.0",
+  "scripts": {
+    "install": "node script.js"
+  }
+}

__tests__/fixtures/add/integrity-pure-lockfile/package-a/script.js

@@ -0,0 +1,3 @@
+var fs = require('fs');
+
+fs.writeFileSync('temp.txt', 'TEST');

__tests__/fixtures/add/integrity-pure-lockfile/package.json

@@ -0,0 +1,6 @@
+{
+  "private": true,
+  "dependencies": {
+    "package-a": "file:./package-a"
+  }
+}

__tests__/fixtures/add/integrity-pure-lockfile/yarn.lock

@@ -0,0 +1,6 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"package-a@file:./package-a":
+  version "1.0.0"

src/cli/commands/install.js

@@ -637,11 +637,6 @@ export class Install {
    */
 
   async saveLockfileAndIntegrity(patterns: Array<string>, workspaceLayout: ?WorkspaceLayout): Promise<void> {
-    // --no-lockfile or --pure-lockfile flag
-    if (this.flags.lockfile === false || this.flags.pureLockfile) {
-      return;
-    }
-
     const resolvedPatterns: {[packagePattern: string]: Manifest} = {};
     Object.keys(this.resolver.patterns).forEach(pattern => {
       if (!workspaceLayout || !workspaceLayout.getManifestByPattern(pattern)) {
@@ -667,6 +662,11 @@ export class Install {
       this.scripts.getArtifacts(),
     );
 
+    // --no-lockfile or --pure-lockfile flag
+    if (this.flags.lockfile === false || this.flags.pureLockfile) {
+      return;
+    }
+
     const lockFileHasAllPatterns = patterns.every(p => this.lockfile.getLocked(p));
     const resolverPatternsAreSameAsInLockfile = Object.keys(lockfileBasedOnResolver).every(pattern => {
       const manifest = this.lockfile.getLocked(pattern);

yarn.lock

@@ -2712,14 +2712,10 @@ istanbul-api@^1.1.0-alpha.1:
     mkdirp "^0.5.1"
     once "^1.4.0"
 
-istanbul-lib-coverage@^1.0.0, istanbul-lib-coverage@^1.1.1:
+istanbul-lib-coverage@^1.0.0, istanbul-lib-coverage@^1.1.0, istanbul-lib-coverage@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/istanbul-lib-coverage/-/istanbul-lib-coverage-1.1.1.tgz#73bfb998885299415c93d38a3e9adf784a77a9da"
 
-istanbul-lib-coverage@^1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/istanbul-lib-coverage/-/istanbul-lib-coverage-1.1.0.tgz#caca19decaef3525b5d6331d701f3f3b7ad48528"
-
 istanbul-lib-hook@^1.0.7:
   version "1.0.7"
   resolved "https://registry.yarnpkg.com/istanbul-lib-hook/-/istanbul-lib-hook-1.0.7.tgz#dd6607f03076578fe7d6f2a630cf143b49bacddc"