fix: reading data from spawned process (#5877)

packages/build/src/plugins/ipc.js

@@ -39,8 +39,8 @@ export const getEventFromChild = async function (childProcess, callId) {
     throw getChildExitError('Could not receive event from child process because it already exited.')
   }
 
-  const messagePromise = pEvent(childProcess, 'message', { filter: ([actualCallId]) => actualCallId === callId })
-  const errorPromise = pEvent(childProcess, 'message', { filter: ([actualCallId]) => actualCallId === 'error' })
+  const messagePromise = pEvent(childProcess, 'message', { filter: (data) => data?.[0] === callId })
+  const errorPromise = pEvent(childProcess, 'message', { filter: (data) => data?.[0] === 'error' })
   const exitPromise = pEvent(childProcess, 'exit', { multiArgs: true })
   try {
     return await Promise.race([getMessage(messagePromise), getError(errorPromise), getExit(exitPromise)])

packages/build/tests/plugins/fixtures/process_send_object/manifest.yml

@@ -0,0 +1,2 @@
+name: test
+inputs: []

packages/build/tests/plugins/fixtures/process_send_object/netlify.toml

@@ -0,0 +1,2 @@
+[[plugins]]
+package = "./plugin.js"

packages/build/tests/plugins/fixtures/process_send_object/plugin.js

@@ -0,0 +1,5 @@
+import process from 'process';
+
+export const onPreBuild = function () {
+  process.send({});
+}

packages/build/tests/plugins/tests.js

@@ -401,3 +401,8 @@ test('Plugins have a pre-populated Blobs context', async (t) => {
 
   t.is(netlifyConfig.build.command, `echo ""Hello there""`)
 })
+
+test('Plugins can respond anything to parent process', async (t) => {
+  const build = await new Fixture('./fixtures/process_send_object').runBuildBinary()
+  t.true(build.exitCode === 0)
+})