fix: print errors when --json option used

.changeset/sharp-masks-leave.md

@@ -0,0 +1,5 @@
+---
+"pnpm": patch
+---
+
+The fatal error should be printed in JSON format, when running a pnpm command with the `--json` option [#5710](https://github.com/pnpm/pnpm/issues/5710).

pnpm/src/errorHandler.ts

@@ -1,23 +1,30 @@
 import { logger } from '@pnpm/logger'
 import { REPORTER_INITIALIZED } from './main'
 
-export function errorHandler (error: Error) {
+export function errorHandler (error: Error & { code?: string }) {
+  if (error.name != null && error.name !== 'pnpm' && !error.name.startsWith('pnpm:')) {
+    try {
+      error.name = 'pnpm'
+    } catch {
+      // Sometimes the name property is read-only
+    }
+  }
+
   if (!global[REPORTER_INITIALIZED]) {
-    console.log(error)
+    // print parseable error on unhandled exception
+    console.log(JSON.stringify({
+      error: {
+        code: error.code ?? error.name,
+        message: error.message,
+      },
+    }, null, 2))
     process.exitCode = 1
     return
   }
   if (global[REPORTER_INITIALIZED] === 'silent') {
     process.exitCode = 1
     return
   }
-  if (error.name != null && error.name !== 'pnpm' && !error.name.startsWith('pnpm:')) {
-    try {
-      error.name = 'pnpm'
-    } catch {
-      // Sometimes the name property is read-only
-    }
-  }
 
   // bole passes only the name, message and stack of an error
   // that is why we pass error as a message as well, to pass

pnpm/src/main.ts

@@ -138,8 +138,8 @@ export async function main (inputArgv: string[]) {
       cmd,
       config,
     })
+    global[REPORTER_INITIALIZED] = reporterType
   }
-  global[REPORTER_INITIALIZED] = reporterType
 
   const selfUpdate = config.global && (cmd === 'add' || cmd === 'update') && cliParams.includes(packageManager.name)
 

pnpm/test/errorHandler.test.ts

@@ -0,0 +1,37 @@
+import { prepare, preparePackages } from '@pnpm/prepare'
+import writeYamlFile from 'write-yaml-file'
+import { execPnpmSync } from './utils'
+
+test('should print json format error when publish --json failed', async () => {
+  prepare({
+    name: 'test-publish-package-no-version',
+    version: undefined,
+  })
+
+  const { status, stdout } = execPnpmSync(['publish', '--dry-run', '--json'])
+
+  expect(status).toBe(1)
+  const { error } = JSON.parse(stdout.toString())
+  expect(error?.code).toBe('ERR_PNPM_PACKAGE_VERSION_NOT_FOUND')
+  expect(error?.message).toBe('Package version is not defined in the package.json.')
+})
+
+test('should print json format error when add dependency on workspace root', async () => {
+  preparePackages([
+    {
+      name: 'project-a',
+      version: '1.0.0',
+    },
+    {
+      name: 'project-b',
+      version: '1.0.0',
+    },
+  ])
+  await writeYamlFile('pnpm-workspace.yaml', { packages: ['**', '!store/**'] })
+
+  const { status, stdout } = execPnpmSync(['add', 'nanoid', '-p'])
+
+  expect(status).toBe(1)
+  const { error } = JSON.parse(stdout.toString())
+  expect(error?.code).toBe('ERR_PNPM_ADDING_TO_ROOT')
+})