Put yarn into silent mode when calling nested yarn run commands (#3536)

Author: Sebastian McKenzie

src/cli/commands/run.js

@@ -75,6 +75,8 @@ export async function run(config: Config, reporter: Reporter, flags: Object, arg
     }
 
     if (cmds.length) {
+      // propagate YARN_SILENT env variable to executed commands
+      process.env.YARN_SILENT = '1';
       for (const [stage, cmd] of cmds) {
         // only tack on trailing arguments for default script, ignore for pre and post - #1595
         const defaultScriptCmd = `${cmd} ${sanitizedArgs(args).join(' ')}`;

src/cli/index.js

@@ -118,7 +118,7 @@ const reporter = new Reporter({
   emoji: process.stdout.isTTY && commander.emoji,
   verbose: commander.verbose,
   noProgress: !commander.progress,
-  isSilent: commander.silent,
+  isSilent: process.env.YARN_SILENT === '1' || commander.silent,
 });
 
 reporter.initPeakMemoryCounter();