13 - Make page language sticky across re-crawls when new fetch returns null

app/Jobs/ProcessCrawlJob.php

@@ -84,8 +84,14 @@ private function updatePageStatus(FetchResult $result): void
                 'status' => $status,
                 'fetched_at' => now(),
                 'title' => $result->title,
-                'language' => $result->language,
-                'language_confidence' => $result->languageConfidence,
+                // Sticky language: only write when detection produced a value, so a re-crawl
+                // returning null doesn't erase a previously-detected language. Guarding on
+                // language alone is sufficient because FetchPageAction::detectLanguage()
+                // always returns the pair as both-null or both-non-null (never mixed).
+                ...($result->language !== null ? [
+                    'language' => $result->language,
+                    'language_confidence' => $result->languageConfidence,
+                ] : []),
             ],
             PageStatusEnum::Failed => [
                 'status' => $status,

tests/Feature/Jobs/ProcessCrawlJobTest.php

@@ -482,7 +482,43 @@ public function test_handle_persists_language_on_success(): void
         $this->assertEqualsWithDelta(0.95, $fresh->language_confidence, 0.001);
     }
 
-    public function test_handle_persists_null_language_on_success(): void
+    public function test_handle_does_not_overwrite_existing_language_when_new_fetch_returns_null(): void
+    {
+        Queue::fake();
+
+        $this->mockFetchPageAction(
+            CrawlOutcomeEnum::Success,
+            statusCode: 200,
+            title: 'Hello',
+            extractedText: 'hi',
+            wordCount: 1,
+            language: null,
+            languageConfidence: null,
+        );
+
+        // Page already has a language from a previous fetch
+        $page = Page::factory()->createQuietly([
+            'url' => 'https://example.com/article',
+            'language' => 'en',
+            'language_confidence' => 0.95,
+        ]);
+        $crawl = PageCrawl::factory()->page($page)->createQuietly();
+
+        app(ProcessCrawlJob::class, ['pageCrawl' => $crawl])
+            ->handle();
+
+        $fresh = $page->fresh();
+
+        // Language columns must be sticky — null detection must NOT overwrite them
+        $this->assertSame('en', $fresh->language);
+        $this->assertEqualsWithDelta(0.95, $fresh->language_confidence, 0.001);
+
+        // Other columns must still update — sticky applies to language only
+        $this->assertSame(PageStatusEnum::Fetched, $fresh->status);
+        $this->assertSame('Hello', $fresh->title);
+    }
+
+    public function test_handle_leaves_language_null_when_no_prior_and_no_detection(): void
     {
         Queue::fake();