fix: add final newlines to serialized JSON files

packages/zpm-constraints/index.ts

@@ -350,7 +350,7 @@ async function main() {
 
   const output = applyEngineReport(FIX);
 
-  writeFileSync(RESULT_PATH, JSON.stringify(output, null, 2));
+  writeFileSync(RESULT_PATH, `${JSON.stringify(output, null, 2)}\n`);
 }
 
 main();

packages/zpm-switch/src/cache.rs

@@ -173,7 +173,7 @@ pub async fn ensure<R: Future<Output = Result<(), Error>>, F: FnOnce(Path) -> R>
                 f(temp_dir.clone()).await?;
 
                 let meta_content
-                    = JsonDocument::to_string(&key_data)?;
+                    = format!("{}\n", JsonDocument::to_string(&key_data)?);
 
                 temp_dir
                     .with_join_str("meta.json")

packages/zpm-switch/src/daemons.rs

@@ -46,7 +46,7 @@ pub fn register_daemon(entry: &DaemonEntry) -> Result<(), Error> {
         .fs_create_parent()?;
 
     let data
-        = JsonDocument::to_string(entry)?;
+        = format!("{}\n", JsonDocument::to_string(entry)?);
 
     daemon_path.fs_write_atomic(move |tmp_path| {
         use std::os::unix::fs::OpenOptionsExt;

packages/zpm-switch/src/links.rs

@@ -99,7 +99,7 @@ fn save_config(config: &FolderConfig) -> Result<(), Error> {
 
     config_path
         .fs_create_parent()?
-        .fs_write(JsonDocument::to_string(config)?)?;
+        .fs_write(format!("{}\n", JsonDocument::to_string(config)?))?;
 
     Ok(())
 }

packages/zpm/src/build.rs

@@ -291,7 +291,7 @@ impl BuildState {
             .fs_create_parent()?;
 
         let build_state_text
-            = JsonDocument::to_string(self)?;
+            = format!("{}\n", JsonDocument::to_string(self)?);
 
         build_state_path
             .fs_change(build_state_text, false)?;

packages/zpm/src/builtins/node.rs

@@ -205,7 +205,7 @@ pub async fn fetch_nodejs_locator<'a>(context: &InstallContext<'a>, locator: &Lo
             };
 
             let serialized_manifest
-                = JsonDocument::to_string(&manifest)?;
+                = format!("{}\n", JsonDocument::to_string(&manifest)?);
 
             let entries
                 = zpm_formats::tar::entries_from_tar(&tar_data)?

packages/zpm/src/commands/constraints.rs

@@ -83,7 +83,7 @@ impl Constraints {
 
             if should_break {
                 if self.json {
-                    println!("{}", String::from_utf8_lossy(&output.raw_json));
+                    print!("{}", String::from_utf8_lossy(&output.raw_json));
                 }
 
                 if !output.all_workspace_errors.is_empty() {

packages/zpm/src/constraints/constraints.tpl.js

@@ -1216,6 +1216,7 @@ async function main() {
   const defaultConfig = config?.default ?? config;
   await defaultConfig.constraints?.(context);
   const output = applyEngineReport(FIX);
-  (0, import_fs.writeFileSync)(RESULT_PATH, JSON.stringify(output, null, 2));
+  (0, import_fs.writeFileSync)(RESULT_PATH, `${JSON.stringify(output, null, 2)}
+`);
 }
 main();

packages/zpm/src/linker/pnp.rs

@@ -219,7 +219,7 @@ fn generate_split_setup(project: &Project, state: &PnpState) -> Result<(), Error
 
     project.pnp_data_path()
         .fs_create_parent()?
-        .fs_change(JsonDocument::to_string(&state)?, false)?;
+        .fs_change(format!("{}\n", JsonDocument::to_string(&state)?), false)?;
 
     Ok(())
 }

packages/zpm/src/project.rs

@@ -481,7 +481,7 @@ impl Project {
             = self.lockfile_path();
 
         let contents
-            = JsonDocument::to_string_pretty(lockfile)?;
+            = format!("{}\n", JsonDocument::to_string_pretty(lockfile)?);
 
         if self.config.settings.enable_immutable_installs.value {
             let current_content = lockfile_path

scripts/import-artifacts.mjs

@@ -72,7 +72,7 @@ runExit(class ImportArtifactsCommand extends Command {
     });
 
     const entries = JSON.parse(dump);
-    const serialized = JSON.stringify(entries);
+    const serialized = `${JSON.stringify(entries)}\n`;
 
     await fs.writeFile(outputPath, serialized);
 

tests/acceptance-tests/pkg-tests-specs/sources/commands/install.test.ts

@@ -96,6 +96,30 @@ describe(`Commands`, () => {
       }),
     );
 
+    test(
+      `it should write a stable lockfile with a final newline`,
+      makeTemporaryEnv({}, async ({path, run}) => {
+        const lockfilePath = ppath.join(path, Filename.lockfile);
+
+        await run(`install`);
+        const lockfileContent = await xfs.readFilePromise(lockfilePath, `utf8`);
+        expect(lockfileContent).toMatch(/[^\n]\n$/);
+
+        await run(`install`, `--force`);
+        await run(`install`, `--immutable`);
+        expect(await xfs.readFilePromise(lockfilePath, `utf8`)).toEqual(lockfileContent);
+
+        const unterminatedContent = lockfileContent.slice(0, -1);
+        await xfs.writeFilePromise(lockfilePath, unterminatedContent);
+
+        await expect(run(`install`, `--immutable`)).rejects.toThrow(/The lockfile would have been modified by this install/);
+        expect(await xfs.readFilePromise(lockfilePath, `utf8`)).toEqual(unterminatedContent);
+
+        await run(`install`);
+        expect(await xfs.readFilePromise(lockfilePath, `utf8`)).toEqual(lockfileContent);
+      }),
+    );
+
     test(
       `it should refuse to create a lockfile when using --immutable`,
       makeTemporaryEnv({

yarn.lock

@@ -18852,4 +18852,4 @@
       }
     }
   }
-}
+}