From 4532cbe006059c90b2787ce0d18c7c8809fe65ea Mon Sep 17 00:00:00 2001
From: Edgar J San Martin <29460583+ej-sanmartin@users.noreply.github.com>
Date: Sun, 28 Dec 2025 01:11:15 -0500
Subject: [PATCH 1/3] Disable threaded imports when WorkerThreadPool has
 insufficient threads.

---
 editor/file_system/editor_file_system.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/editor/file_system/editor_file_system.cpp b/editor/file_system/editor_file_system.cpp
index a286f0956f..94d64c29c9 100644
--- a/editor/file_system/editor_file_system.cpp
+++ b/editor/file_system/editor_file_system.cpp
@@ -3287,6 +3287,15 @@ void EditorFileSystem::reimport_files(const Vector<String> &p_files) {
 
 #ifdef THREADS_ENABLED
 	bool use_multiple_threads = GLOBAL_GET("editor/import/use_multiple_threads");
+#ifdef WEB_ENABLED
+	// The Web platform may have threading compiled in, but with only 1 available thread (the main thread).
+	// Using threaded imports with a single thread causes a deadlock as the main thread waits in a busy-loop
+	// while the import tasks can't execute. Disable threaded imports when insufficient threads are available.
+	// See GH-112072 for details.
+	if (WorkerThreadPool::get_singleton()->get_thread_count() <= 1) {
+		use_multiple_threads = false;
+	}
+#endif
 #else
 	bool use_multiple_threads = false;
 #endif

From 7278190c71159026142438beee40bec9c7d75e69 Mon Sep 17 00:00:00 2001
From: Edgar <29460583+ej-sanmartin@users.noreply.github.com>
Date: Sun, 28 Dec 2025 21:29:16 -0500
Subject: [PATCH 2/3] Disable threaded scanning and importing on Web platform.

---
 editor/file_system/editor_file_system.cpp | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/editor/file_system/editor_file_system.cpp b/editor/file_system/editor_file_system.cpp
index 94d64c29c9..17c92d1b23 100644
--- a/editor/file_system/editor_file_system.cpp
+++ b/editor/file_system/editor_file_system.cpp
@@ -3285,17 +3285,13 @@ void EditorFileSystem::reimport_files(const Vector<String> &p_files) {
 	// Emit the resource_reimporting signal for the single file before the actual importation.
 	emit_signal(SNAME("resources_reimporting"), reloads);
 
-#ifdef THREADS_ENABLED
-	bool use_multiple_threads = GLOBAL_GET("editor/import/use_multiple_threads");
 #ifdef WEB_ENABLED
-	// The Web platform may have threading compiled in, but with only 1 available thread (the main thread).
-	// Using threaded imports with a single thread causes a deadlock as the main thread waits in a busy-loop
-	// while the import tasks can't execute. Disable threaded imports when insufficient threads are available.
+	// On web, busy-wait loops on the main thread block the JavaScript event loop,
+	// causing the browser tab to appear frozen. Disable threaded imports entirely.
 	// See GH-112072 for details.
-	if (WorkerThreadPool::get_singleton()->get_thread_count() <= 1) {
-		use_multiple_threads = false;
-	}
-#endif
+	bool use_multiple_threads = false;
+#elif defined(THREADS_ENABLED)
+	bool use_multiple_threads = GLOBAL_GET("editor/import/use_multiple_threads");
 #else
 	bool use_multiple_threads = false;
 #endif
@@ -3759,7 +3755,7 @@ void EditorFileSystem::remove_import_format_support_query(Ref<EditorFileSystemIm
 }
 
 EditorFileSystem::EditorFileSystem() {
-#ifdef THREADS_ENABLED
+#if defined(THREADS_ENABLED) && !defined(WEB_ENABLED)
 	use_threads = true;
 #endif
 

From 2c29a37840514f686b220123ea9d0fdd9dd12976 Mon Sep 17 00:00:00 2001
From: Edgar <29460583+ej-sanmartin@users.noreply.github.com>
Date: Sun, 28 Dec 2025 21:35:21 -0500
Subject: [PATCH 3/3] Add clarifying comment explaining threads block file
 system scanning on web.

---
 editor/file_system/editor_file_system.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/editor/file_system/editor_file_system.cpp b/editor/file_system/editor_file_system.cpp
index 17c92d1b23..cdfb403f2f 100644
--- a/editor/file_system/editor_file_system.cpp
+++ b/editor/file_system/editor_file_system.cpp
@@ -3756,6 +3756,8 @@ void EditorFileSystem::remove_import_format_support_query(Ref<EditorFileSystemIm
 
 EditorFileSystem::EditorFileSystem() {
 #if defined(THREADS_ENABLED) && !defined(WEB_ENABLED)
+	// On web, threaded scanning blocks the browser's event loop, causing freezes.
+	// See GH-112072 for details.
 	use_threads = true;
 #endif