fix: warn when no lockfile present (package-lock.json | npm-shrinkwrap.json) [#852]

src/nodejs/supply/supply.go

@@ -439,24 +439,25 @@ func (s *Supplier) ReadPackageJSON() error {
 }
 
 func (s *Supplier) NoPackageLockTip() error {
+	// Only consider npm lockfiles for this check.
 	lockFiles := []string{"package-lock.json", "npm-shrinkwrap.json"}
-	if s.UseYarn {
-		lockFiles = []string{"yarn.lock"}
-	}
 
+	// Determine whether any of the supported npm lock files exist.
+	anyExists := false
 	for _, lockFile := range lockFiles {
-		lockFileExists, err := libbuildpack.FileExists(filepath.Join(s.Stager.BuildDir(), lockFile))
+		exists, err := libbuildpack.FileExists(filepath.Join(s.Stager.BuildDir(), lockFile))
 		if err != nil {
 			return err
 		}
-
-		if lockFileExists {
-			return nil
+		if exists {
+			anyExists = true
+			break
 		}
+	}
 
-		if s.IsVendored {
-			s.Log.Protip("Warning: package-lock.json not found. The buildpack may reach out to the internet to download module updates, even if they are vendored.", "https://docs.cloudfoundry.org/buildpacks/node/index.html#offline_environments")
-		}
+	// Only warn if none of the npm lockfiles exist and the app has vendored deps.
+	if !anyExists && s.IsVendored {
+		s.Log.Protip("Warning: package-lock.json or npm-shrinkwrap.json not found. The buildpack may reach out to the internet to download module updates, even if they are vendored.", "https://docs.cloudfoundry.org/buildpacks/node/index.html#offline_environments")
 	}
 
 	return nil

src/nodejs/supply/supply_test.go

@@ -1497,4 +1497,25 @@ export PATH=$PATH:"$HOME/bin":$NODE_PATH/.bin
 			Expect(string(contents)).To(ContainSubstring("export SSL_CERT_DIR=${SSL_CERT_DIR:-/etc/ssl/certs}"))
 		})
 	})
+
+	Describe("NoPackageLockTip", func() {
+		It("does not log when npm-shrinkwrap.json exists and vendored", func() {
+			Expect(os.WriteFile(filepath.Join(buildDir, "npm-shrinkwrap.json"), []byte("{}"), 0644)).To(Succeed())
+			supplier.IsVendored = true
+			err = supplier.NoPackageLockTip()
+			Expect(err).To(BeNil())
+			Expect(buffer.String()).To(Equal(""))
+		})
+
+		It("logs when no lockfile exists and vendored", func() {
+			// Ensure no lock files are present
+			os.Remove(filepath.Join(buildDir, "package-lock.json"))
+			os.Remove(filepath.Join(buildDir, "npm-shrinkwrap.json"))
+			supplier.IsVendored = true
+			buffer.Reset()
+			err = supplier.NoPackageLockTip()
+			Expect(err).To(BeNil())
+			Expect(buffer.String()).To(ContainSubstring("not found"))
+		})
+	})
 })