fix: don't pipe plugin output more than once at the time

Author: pieh

packages/build/src/log/stream.ts

@@ -47,13 +47,21 @@ const pushBuildCommandOutput = function (output: string, logsArray: string[]) {
   logsArray.push(output)
 }
 
+const pipedPluginProcesses = new WeakMap<ChildProcess, ReturnType<typeof pipePluginOutput>>()
+
 // Start plugin step output
 export const pipePluginOutput = function (childProcess: ChildProcess, logs: Logs, standardStreams: StandardStreams) {
-  if (!logsAreBuffered(logs)) {
-    return streamOutput(childProcess, standardStreams)
+  if (pipedPluginProcesses.has(childProcess)) {
+    return pipedPluginProcesses.get(childProcess)
   }
 
-  return pushOutputToLogs(childProcess, logs, standardStreams.outputFlusher)
+  const listeners = !logsAreBuffered(logs)
+    ? streamOutput(childProcess, standardStreams)
+    : pushOutputToLogs(childProcess, logs, standardStreams.outputFlusher)
+
+  pipedPluginProcesses.set(childProcess, listeners)
+
+  return listeners
 }
 
 // Stop streaming/buffering plugin step output
@@ -71,6 +79,8 @@ export const unpipePluginOutput = async function (
   }
 
   unpushOutputToLogs(childProcess, listeners.stdoutListener, listeners.stderrListener)
+
+  pipedPluginProcesses.delete(childProcess)
 }
 
 // Usually, we stream stdout/stderr because it is more efficient