fix: Do not print duplicate stdio after a streaming command errors (#1832)

Fixes #1790

Author: mnutt

core/command/__tests__/command.test.js

@@ -198,6 +198,33 @@ describe("core-command", () => {
         });
       }
     });
+
+    it("does not log stdout/stderr after streaming ends", async () => {
+      class PkgErrorCommand extends Command {
+        initialize() {
+          return true;
+        }
+
+        execute() {
+          const err = new Error("message");
+
+          err.cmd = "test-pkg-err";
+          err.stdout = "pkg-err-stdout";
+          err.stderr = "pkg-err-stderr";
+          err.pkg = {
+            name: "pkg-err-name",
+          };
+
+          throw err;
+        }
+      }
+
+      try {
+        await new PkgErrorCommand({ cwd: testDir, stream: true });
+      } catch (err) {
+        expect(console.error.mock.calls).toHaveLength(0);
+      }
+    });
   });
 
   describe("loglevel", () => {

core/command/index.js

@@ -59,7 +59,7 @@ class Command {
         err => {
           if (err.pkg) {
             // Cleanly log specific package error details
-            logPackageError(err);
+            logPackageError(err, this.options.stream);
           } else if (err.name !== "ValidationError") {
             // npmlog does some funny stuff to the stack by default,
             // so pass it directly to avoid duplication.

core/command/lib/log-package-error.js

@@ -4,9 +4,14 @@ const log = require("libnpm/log");
 
 module.exports = logPackageError;
 
-function logPackageError(err) {
+function logPackageError(err, stream = false) {
   log.error(err.cmd, `exited ${err.code} in '${err.pkg.name}'`);
 
+  if (stream) {
+    // Streaming has already printed all stdout/stderr
+    return;
+  }
+
   if (err.stdout) {
     log.error(err.cmd, "stdout:");
     directLog(err.stdout);