From 0466aeab53db7aad3cc7c9aab094c24af728e15c Mon Sep 17 00:00:00 2001
From: Colin Casey <casey.colin@gmail.com>
Date: Fri, 24 Nov 2023 14:51:54 -0400
Subject: [PATCH 1/2] Gracefully handle error when trying to read
 `package.json` in detect

This change prevents the detection routine from raising an error during detect if:
- there is no `package.json`
- there is a `package.json` but it cannot be read for some reason

Both error cases will be handled and report a failed detect.
---
 buildpacks/nodejs-npm-install/CHANGELOG.md    |  4 +++
 buildpacks/nodejs-npm-install/src/main.rs     | 29 ++++++++++---------
 .../tests/fixtures/empty/.gitkeep             |  0
 .../tests/integration_test.rs                 | 14 +++++++++
 4 files changed, 33 insertions(+), 14 deletions(-)
 create mode 100644 buildpacks/nodejs-npm-install/tests/fixtures/empty/.gitkeep

diff --git a/buildpacks/nodejs-npm-install/CHANGELOG.md b/buildpacks/nodejs-npm-install/CHANGELOG.md
index d4f3cc405..0b7e4b863 100644
--- a/buildpacks/nodejs-npm-install/CHANGELOG.md
+++ b/buildpacks/nodejs-npm-install/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Detection will report a failure instead of throwing an error when there is no `package.json` file in the application directory.
+
 ## [2.3.0] - 2023-11-09
 
 - No changes.
diff --git a/buildpacks/nodejs-npm-install/src/main.rs b/buildpacks/nodejs-npm-install/src/main.rs
index 149c32f8e..c90efc8de 100644
--- a/buildpacks/nodejs-npm-install/src/main.rs
+++ b/buildpacks/nodejs-npm-install/src/main.rs
@@ -46,20 +46,21 @@ impl Buildpack for NpmInstallBuildpack {
             .try_exists()
             .map_err(NpmInstallBuildpackError::Detect)?;
 
-        let package_json = PackageJson::read(context.app_dir.join("package.json"))
-            .map_err(NpmInstallBuildpackError::PackageJson)?;
-
-        if npm_lockfile_exists || package_json.has_dependencies() {
-            DetectResultBuilder::pass()
-                .build_plan(
-                    BuildPlanBuilder::new()
-                        .provides("node_modules")
-                        .requires("npm")
-                        .requires("node_modules")
-                        .requires("node")
-                        .build(),
-                )
-                .build()
+        if let Ok(package_json) = PackageJson::read(context.app_dir.join("package.json")) {
+            if npm_lockfile_exists || package_json.has_dependencies() {
+                DetectResultBuilder::pass()
+                    .build_plan(
+                        BuildPlanBuilder::new()
+                            .provides("node_modules")
+                            .requires("npm")
+                            .requires("node_modules")
+                            .requires("node")
+                            .build(),
+                    )
+                    .build()
+            } else {
+                DetectResultBuilder::fail().build()
+            }
         } else {
             DetectResultBuilder::fail().build()
         }
diff --git a/buildpacks/nodejs-npm-install/tests/fixtures/empty/.gitkeep b/buildpacks/nodejs-npm-install/tests/fixtures/empty/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/buildpacks/nodejs-npm-install/tests/integration_test.rs b/buildpacks/nodejs-npm-install/tests/integration_test.rs
index f5ce04a8a..c7bfbde96 100644
--- a/buildpacks/nodejs-npm-install/tests/integration_test.rs
+++ b/buildpacks/nodejs-npm-install/tests/integration_test.rs
@@ -172,6 +172,20 @@ fn test_dependencies_and_missing_lockfile_errors() {
     );
 }
 
+#[test]
+#[ignore]
+fn detect_rejects_non_npm_project() {
+    nodejs_integration_test_with_config(
+        "./fixtures/empty",
+        |config| {
+            config.expected_pack_result(PackResult::Failure);
+        },
+        |ctx| {
+            assert_contains!(ctx.pack_stdout, "fail: heroku/nodejs-npm-install");
+        },
+    );
+}
+
 fn add_lockfile_entry(app_dir: &Path, package_name: &str, lockfile_entry: serde_json::Value) {
     update_json_file(&app_dir.join("package-lock.json"), |json| {
         let dependencies = json["dependencies"].as_object_mut().unwrap();

From 80f2636d0802b2b7e4164aa41a358bcca74f621f Mon Sep 17 00:00:00 2001
From: Colin Casey <casey.colin@gmail.com>
Date: Fri, 24 Nov 2023 14:53:45 -0400
Subject: [PATCH 2/2] Update CHANGELOG.md

---
 buildpacks/nodejs-npm-install/CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/buildpacks/nodejs-npm-install/CHANGELOG.md b/buildpacks/nodejs-npm-install/CHANGELOG.md
index 0b7e4b863..4782d0a7d 100644
--- a/buildpacks/nodejs-npm-install/CHANGELOG.md
+++ b/buildpacks/nodejs-npm-install/CHANGELOG.md
@@ -9,7 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
-- Detection will report a failure instead of throwing an error when there is no `package.json` file in the application directory.
+- Detection will report a failure instead of throwing an error when there is no `package.json` file in the application directory. ([#733](https://github.com/heroku/buildpacks-nodejs/pull/733))
 
 ## [2.3.0] - 2023-11-09