Tweaks to build_daemon for webdev. (#4034)

Author: davidmorgan

build_runner/bin/build_runner.dart

@@ -80,10 +80,20 @@ Future<void> main(List<String> args) async {
     exitCode = await commandRunner.runCommand(parsedArgs) ?? 1;
   } else {
     var experiments = parsedArgs.command!['enable-experiment'] as List<String>?;
-    if ({'build', 'serve', 'watch', 'test'}.contains(commandName)) {
-      buildLog.configuration = buildLog.configuration.rebuild((b) {
-        b.mode = BuildLogMode.build;
-      });
+    // Set the buildLog mode before the command starts so the first few log
+    // messages are displayed correctly.
+    switch (commandName) {
+      case 'build':
+      case 'serve':
+      case 'watch':
+      case 'test':
+        buildLog.configuration = buildLog.configuration.rebuild((b) {
+          b.mode = BuildLogMode.build;
+        });
+      case 'daemon':
+        buildLog.configuration = buildLog.configuration.rebuild((b) {
+          b.mode = BuildLogMode.daemon;
+        });
     }
     while ((exitCode = await generateAndRun(args, experiments: experiments)) ==
         ExitCode.tempFail.code) {}

build_runner/lib/src/entrypoint/daemon.dart

@@ -99,6 +99,8 @@ class DaemonCommand extends WatchCommand {
       // These are serialized between special `<log-record>` and `</log-record>`
       // tags to make parsing them on stdout easier. They can have multiline
       // strings so we can't just serialize the json on a single line.
+      //
+      // `BuildRunnerDaemonBuilder` sets its own `onLog` replacing this one.
       buildLog.configuration = buildLog.configuration.rebuild((b) {
         b.onLog =
             (record) => stdout.writeln('''
@@ -111,9 +113,6 @@ $logEndMarker''');
         builderApplications,
         options,
       );
-      buildLog.configuration = buildLog.configuration.rebuild((b) {
-        b.onLog = null;
-      });
 
       // Forward server logs to daemon command STDIO.
       var logSub = builder.logs.listen((log) {

build_runner_core/lib/src/environment/create_merged_dir.dart

@@ -68,9 +68,6 @@ Future<bool> createMergedOutputDirectories(
           outputSymlinksOnly || outputLocation.useSymlinks,
           outputLocation.hoist,
         )) {
-          buildLog.error(
-            'Unable to create merged directory for ${outputLocation.path}.',
-          );
           return false;
         }
       }
@@ -333,9 +330,8 @@ Future<bool> _cleanUpOutputDir(
         );
       } on NonInteractiveBuildException catch (_) {
         buildLog.error(
-          'Unable to create merged directory at $outputPath.\n'
-          'Choose a different directory or delete the contents of that '
-          'directory.',
+          'Unable to create merged directory $outputPath. Choose a different '
+          'directory or delete the contents of that directory.',
         );
         return false;
       }

build_runner_core/lib/src/logging/log_display.dart

@@ -101,9 +101,14 @@ class LogDisplay {
     _logger.log(severity.toLogLevel, message);
 
     // Display.
-    if (buildLog.configuration.mode == BuildLogMode.daemon &&
-        severity == Severity.error) {
-      stderr.writeln(_render(severity, message));
+    if (buildLog.configuration.mode == BuildLogMode.daemon) {
+      // For `build_daemon` just display the messages, severity is determined
+      // by stderr vs stdout.
+      if (severity == Severity.error) {
+        stderr.writeln(message);
+      } else {
+        stdout.writeln(message);
+      }
     } else {
       stdout.writeln(_render(severity, message));
     }