Report live reload build failures

src/Console/ServeCommand.php

@@ -7,6 +7,7 @@
 use YiiPress\Environment;
 use YiiPress\RuntimePaths;
 use YiiPress\Web\DevServer\DevHtmlInjector;
+use YiiPress\Web\LiveReload\SiteBuildResult;
 use YiiPress\Web\LiveReload\SiteBuildRunner;
 use FilesystemIterator;
 use HttpSoft\Message\ServerRequest;
@@ -412,8 +413,21 @@ function (): void {
                 return;
             }
 
-            $this->buildLiveReloadSite();
-            $this->broadcastLiveReloadEvent('reload', 'changed', true);
+            $result = $this->buildLiveReloadSite();
+            if ($result === null) {
+                return;
+            }
+
+            if ($result->succeeded()) {
+                $this->broadcastLiveReloadEvent('reload', 'changed', true);
+                return;
+            }
+
+            $this->broadcastLiveReloadEvent(
+                'build-error',
+                json_encode(['output' => $result->output], JSON_THROW_ON_ERROR),
+                true,
+            );
         });
     }
 
@@ -461,15 +475,15 @@ private function closeLiveReloadWatcher(): void
         $this->liveReloadClients = [];
     }
 
-    private function buildLiveReloadSite(): void
+    private function buildLiveReloadSite(): ?SiteBuildResult
     {
         $now = microtime(true);
         if ($now - $this->lastLiveReloadBuildTime < 1.0) {
-            return;
+            return null;
         }
 
         $this->lastLiveReloadBuildTime = $now;
-        $this->createLiveReloadBuildRunner()->build();
+        return $this->createLiveReloadBuildRunner()->build();
     }
 
     private function finishLiveReloadResponse(ConnectionInterface $connection, string $event, string $data): void

src/Web/DevServer/assets/live-reload.js

@@ -19,6 +19,17 @@
         }
         es = new EventSource("/_live-reload");
         es.addEventListener("reload", function() { es.close(); location.reload(); });
+        es.addEventListener("build-error", function(event) {
+            es.close();
+            try {
+                var payload = JSON.parse(event.data);
+                if (payload.output) {
+                    console.error(payload.output);
+                }
+            } catch (error) {
+                console.error(event.data);
+            }
+        });
         es.addEventListener("ping", function() {});
         es.onerror = function() {
             es.close();

src/Web/LiveReload/SiteBuildResult.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace YiiPress\Web\LiveReload;
+
+final readonly class SiteBuildResult
+{
+    public function __construct(
+        public int $exitCode,
+        public string $output,
+    ) {}
+
+    public function succeeded(): bool
+    {
+        return $this->exitCode === 0;
+    }
+}

src/Web/LiveReload/SiteBuildRunner.php

@@ -12,7 +12,7 @@ public function __construct(
         private string $outputDir,
     ) {}
 
-    public function build(): bool
+    public function build(): SiteBuildResult
     {
         $command = escapeshellarg($this->yiiBinary)
             . ' build'
@@ -22,6 +22,6 @@ public function build(): bool
 
         exec($command, $output, $exitCode);
 
-        return $exitCode === 0;
+        return new SiteBuildResult($exitCode, implode("\n", $output));
     }
 }

tests/Unit/Web/LiveReload/SiteBuildRunnerTest.php

@@ -52,7 +52,7 @@ public function testBuildUsesIncrementalCommandLine(): void
 
         $runner = new SiteBuildRunner($script, $this->tempDir . '/content', $this->tempDir . '/output');
 
-        self::assertTrue($runner->build());
+        self::assertTrue($runner->build()->succeeded());
 
         $commandLine = file_get_contents($recordFile);
         assertSame(
@@ -64,15 +64,18 @@ public function testBuildUsesIncrementalCommandLine(): void
         assertStringNotContainsString('--no-cache', $commandLine);
     }
 
-    public function testBuildReturnsFalseWhenCommandFails(): void
+    public function testBuildReturnsFailureResultWhenCommandFails(): void
     {
         $script = $this->tempDir . '/fail-yii';
-        file_put_contents($script, "#!/bin/sh\nexit 1\n");
+        file_put_contents($script, "#!/bin/sh\nprintf 'failed build\n'\nexit 1\n");
         chmod($script, 0o755);
 
         $runner = new SiteBuildRunner($script, $this->tempDir . '/content', $this->tempDir . '/output');
+        $result = $runner->build();
 
-        assertFalse($runner->build());
+        assertFalse($result->succeeded());
+        assertSame(1, $result->exitCode);
+        assertStringContainsString('failed build', $result->output);
     }
 
     private function removeDir(string $path): void