Fix pnpm version detection to respect packageManager field

Both pnpm 9 and 10 use lockfileVersion '9.0', making them
indistinguishable by lockfile alone. This fix prioritizes the
packageManager field in package.json when determining which pnpm
version to use.

Changes:
- Parse packageManager field (e.g., "[email protected]") to extract version
- Map parsed version to appropriate nix package (pnpm-9_x, pnpm-10_x)
- Fall back to lockfile detection only when packageManager is absent
- Default lockfileVersion '9.0' to pnpm-9_x (when introduced)
- Add packageManager field to node-24-pnpm-10 example for pnpm 10
- Update test snapshots

This ensures pnpm 10 is only used when explicitly specified in the
packageManager field, fixing the node-pnpm-corepack example which
was incorrectly using pnpm-10_x instead of pnpm-9_x.

Author: coffee-cup

examples/node-24-pnpm-10/package.json

@@ -7,5 +7,6 @@
   },
   "engines": {
     "node": "24.x"
-  }
+  },
+  "packageManager": "[email protected]"
 }

src/providers/node/mod.rs

@@ -515,18 +515,18 @@ impl NodeProvider {
         }
 
         // Extract version number from package name (e.g., "nodejs_18" -> 18)
-        let version = node_pkg.name
+        let version = node_pkg
+            .name
             .strip_prefix("nodejs_")
             .and_then(|v| v.parse::<u32>().ok())
             .unwrap_or(DEFAULT_NODE_VERSION);
 
         // Look up the archive for this version
-        let archive = version_number_to_archive(version)
-            .unwrap_or_else(|| {
-                // Fallback to default version's archive
-                version_number_to_archive(DEFAULT_NODE_VERSION)
-                    .expect("Default node version must exist in AVAILABLE_NODE_VERSIONS")
-            });
+        let archive = version_number_to_archive(version).unwrap_or_else(|| {
+            // Fallback to default version's archive
+            version_number_to_archive(DEFAULT_NODE_VERSION)
+                .expect("Default node version must exist in AVAILABLE_NODE_VERSIONS")
+        });
 
         Ok(archive.to_string())
     }
@@ -547,18 +547,35 @@ impl NodeProvider {
         pkgs.push(node_pkg);
 
         if package_manager == "pnpm" {
-            let lockfile = app.read_file("pnpm-lock.yaml").unwrap_or_default();
-            if lockfile.starts_with("lockfileVersion: 5.3") {
-                pm_pkg = Pkg::new("pnpm-6_x");
-            } else if lockfile.starts_with("lockfileVersion: 5.4") {
-                pm_pkg = Pkg::new("pnpm-7_x");
-            } else if lockfile.starts_with("lockfileVersion: '6.0'") {
-                pm_pkg = Pkg::new("pnpm-8_x");
-            } else if lockfile.starts_with("lockfileVersion: '9.0'") {
-                pm_pkg = Pkg::new("pnpm-10_x");
+            // First, try to determine version from packageManager field (for corepack)
+            if let Some(ref pkg_manager_field) = package_json.package_manager {
+                if let Some(version_str) = pkg_manager_field.strip_prefix("pnpm@") {
+                    // Parse major version from "[email protected]" -> 9
+                    if let Some(major_version) = version_str.split('.').next() {
+                        if let Ok(major) = major_version.parse::<u32>() {
+                            pm_pkg = match major {
+                                6 => Pkg::new("pnpm-6_x"),
+                                7 => Pkg::new("pnpm-7_x"),
+                                8 => Pkg::new("pnpm-8_x"),
+                                9 => Pkg::new("pnpm-9_x"),
+                                10 => Pkg::new("pnpm-10_x"),
+                                _ => {
+                                    // For unknown versions, try lockfile detection
+                                    NodeProvider::get_pnpm_package_from_lockfile(app)
+                                }
+                            };
+                        } else {
+                            pm_pkg = NodeProvider::get_pnpm_package_from_lockfile(app);
+                        }
+                    } else {
+                        pm_pkg = NodeProvider::get_pnpm_package_from_lockfile(app);
+                    }
+                } else {
+                    pm_pkg = NodeProvider::get_pnpm_package_from_lockfile(app);
+                }
             } else {
-                // Default to pnpm 9
-                pm_pkg = Pkg::new("pnpm-9_x");
+                // Fall back to lockfile-based detection
+                pm_pkg = NodeProvider::get_pnpm_package_from_lockfile(app);
             }
         } else if package_manager == "yarn" {
             pm_pkg = Pkg::new("yarn-1_x");
@@ -667,6 +684,21 @@ impl NodeProvider {
         all_deps
     }
 
+    fn get_pnpm_package_from_lockfile(app: &App) -> Pkg {
+        let lockfile = app.read_file("pnpm-lock.yaml").unwrap_or_default();
+        if lockfile.starts_with("lockfileVersion: 5.3") {
+            Pkg::new("pnpm-6_x")
+        } else if lockfile.starts_with("lockfileVersion: 5.4") {
+            Pkg::new("pnpm-7_x")
+        } else if lockfile.starts_with("lockfileVersion: '6.0'") {
+            Pkg::new("pnpm-8_x")
+        } else if lockfile.starts_with("lockfileVersion: '9.0'") {
+            Pkg::new("pnpm-9_x")
+        } else {
+            Pkg::new("pnpm-9_x")
+        }
+    }
+
     pub fn cache_tsbuildinfo_file(app: &App, build: &mut Phase) {
         let mut ts_config: TsConfigJson = app.read_json("tsconfig.json").unwrap_or_default();
         if let Some(ref extends) = ts_config.extends {
@@ -831,7 +863,7 @@ mod test {
                 &App::new("examples/node")?,
                 &Environment::default()
             )?,
-            Pkg::new(version_number_to_pkg(22).as_str())
+            Pkg::new(version_number_to_pkg(24).as_str())
         );
 
         Ok(())

tests/snapshots/generate_plan_tests__node_24_pnpm_10.snap

@@ -0,0 +1,55 @@
+---
+source: tests/generate_plan_tests.rs
+expression: plan
+---
+{
+  "providers": [],
+  "buildImage": "[build_image]",
+  "variables": {
+    "CI": "true",
+    "NIXPACKS_METADATA": "node",
+    "NODE_ENV": "production",
+    "NPM_CONFIG_PRODUCTION": "false"
+  },
+  "phases": {
+    "build": {
+      "name": "build",
+      "dependsOn": [
+        "install"
+      ],
+      "cacheDirectories": [
+        "node_modules/.cache"
+      ]
+    },
+    "install": {
+      "name": "install",
+      "dependsOn": [
+        "setup"
+      ],
+      "cmds": [
+        "npm install -g [email protected] && corepack enable",
+        "pnpm i --frozen-lockfile"
+      ],
+      "cacheDirectories": [
+        "/root/.local/share/pnpm/store/v3"
+      ],
+      "paths": [
+        "/app/node_modules/.bin"
+      ]
+    },
+    "setup": {
+      "name": "setup",
+      "nixPkgs": [
+        "nodejs_24",
+        "pnpm-10_x"
+      ],
+      "nixOverlays": [
+        "https://github.com/railwayapp/nix-npm-overlay/archive/main.tar.gz"
+      ],
+      "nixpkgsArchive": "[archive]"
+    }
+  },
+  "start": {
+    "cmd": "pnpm run start"
+  }
+}

tests/snapshots/generate_plan_tests__node_pnpm_corepack.snap

@@ -43,7 +43,7 @@ expression: plan
     "setup": {
       "name": "setup",
       "nixPkgs": [
-        "nodejs_22",
+        "nodejs_24",
         "pnpm-9_x"
       ],
       "nixOverlays": [

tests/snapshots/generate_plan_tests__node_pnpm_monorepo.snap

@@ -45,7 +45,7 @@ expression: plan
     "setup": {
       "name": "setup",
       "nixPkgs": [
-        "nodejs_22",
+        "nodejs_24",
         "pnpm-9_x"
       ],
       "nixOverlays": [

tests/snapshots/generate_plan_tests__node_remix.snap

@@ -43,7 +43,7 @@ expression: plan
     "setup": {
       "name": "setup",
       "nixPkgs": [
-        "nodejs_22",
+        "nodejs_24",
         "npm-9_x"
       ],
       "nixOverlays": [

tests/snapshots/generate_plan_tests__node_turborepo.snap

@@ -44,7 +44,7 @@ expression: plan
     "setup": {
       "name": "setup",
       "nixPkgs": [
-        "nodejs_22",
+        "nodejs_24",
         "npm-8_x"
       ],
       "nixOverlays": [