fix(browser): drop OptimizationHints from --disable-features

crawl4ai/browser_manager.py

@@ -85,8 +85,10 @@ def build_browser_flags(config: BrowserConfig) -> List[str]:
             "--force-color-profile=srgb",
             "--mute-audio",
             "--disable-background-timer-throttling",
-            # Memory-saving flags: disable unused Chrome features
-            "--disable-features=OptimizationHints,MediaRouter,DialMediaRouteProvider",
+            # Memory-saving flags: disable unused Chrome features.
+            # Do not disable OptimizationHints — it SEGV_ACCERRs Chrome-for-Testing
+            # under --headless=new on macOS arm64 (issue #2239).
+            "--disable-features=MediaRouter,DialMediaRouteProvider",
             "--disable-component-update",
             "--disable-domain-reliability",
         ]
@@ -1102,8 +1104,10 @@ def _build_browser_args(self) -> dict:
             "--force-color-profile=srgb",
             "--mute-audio",
             "--disable-background-timer-throttling",
-            # Memory-saving flags: disable unused Chrome features
-            "--disable-features=OptimizationHints,MediaRouter,DialMediaRouteProvider",
+            # Memory-saving flags: disable unused Chrome features.
+            # Do not disable OptimizationHints — it SEGV_ACCERRs Chrome-for-Testing
+            # under --headless=new on macOS arm64 (issue #2239).
+            "--disable-features=MediaRouter,DialMediaRouteProvider",
             "--disable-component-update",
             "--disable-domain-reliability",
             # "--single-process",

tests/async/test_browser_memory.py

@@ -187,8 +187,11 @@ async def test_memory_saving_flags_applied(test_server):
         assert any("max-old-space-size" in a for a in args_list), (
             "memory_saving_mode=True should add V8 heap cap"
         )
-        # Always-on flags should be present regardless
-        assert any("OptimizationHints" in a for a in args_list)
+        # Always-on flags should be present regardless.
+        # OptimizationHints must stay off the disable-list (issue #2239).
+        assert any("MediaRouter" in a for a in args_list)
+        assert any("DialMediaRouteProvider" in a for a in args_list)
+        assert not any("OptimizationHints" in a for a in args_list)
 
     async with AsyncWebCrawler(config=config_off) as crawler:
         bm = _bm(crawler)
@@ -201,7 +204,9 @@ async def test_memory_saving_flags_applied(test_server):
             "memory_saving_mode=False should NOT add V8 heap cap"
         )
         # Always-on flags should still be there
-        assert any("OptimizationHints" in a for a in args_list)
+        assert any("MediaRouter" in a for a in args_list)
+        assert any("DialMediaRouteProvider" in a for a in args_list)
+        assert not any("OptimizationHints" in a for a in args_list)
 
 
 # ===========================================================================
@@ -210,15 +215,18 @@ async def test_memory_saving_flags_applied(test_server):
 
 @pytest.mark.asyncio
 async def test_always_on_flags_present(test_server):
-    """The 3 always-on memory flags should appear in _build_browser_args
-    even with default BrowserConfig."""
+    """The always-on memory flags should appear in _build_browser_args
+    even with default BrowserConfig. OptimizationHints must not be disabled
+    (issue #2239 / Chrome-for-Testing SEGV_ACCERR under --headless=new)."""
     config = BrowserConfig(headless=True, verbose=False)
     async with AsyncWebCrawler(config=config) as crawler:
         browser_args = _bm(crawler)._build_browser_args()
         args_list = browser_args.get("args", browser_args) if isinstance(browser_args, dict) else browser_args
         assert any("disable-component-update" in a for a in args_list)
         assert any("disable-domain-reliability" in a for a in args_list)
-        assert any("OptimizationHints" in a for a in args_list)
+        assert any("MediaRouter" in a for a in args_list)
+        assert any("DialMediaRouteProvider" in a for a in args_list)
+        assert not any("OptimizationHints" in a for a in args_list)
 
 
 # ===========================================================================

tests/regression/test_reg_browser.py

@@ -131,6 +131,51 @@ async def test_browser_context_manager(local_server):
     # If we get here without exception, cleanup succeeded
 
 
+# ---------------------------------------------------------------------------
+# Launch flags
+# ---------------------------------------------------------------------------
+
+
+def _disable_feature_names(args):
+    """Every name listed in any --disable-features switch (not last-wins)."""
+    names = []
+    for arg in args:
+        if arg.startswith("--disable-features="):
+            names.extend(
+                name.strip()
+                for name in arg.split("=", 1)[1].split(",")
+                if name.strip()
+            )
+    return names
+
+
+def test_disable_features_omits_optimization_hints():
+    """Issue #2239: OptimizationHints in --disable-features crashes
+    Chrome-for-Testing under --headless=new on macOS arm64 (SEGV_ACCERR).
+
+    MediaRouter and DialMediaRouteProvider must remain. #2219 merges
+    repeated --disable-features lists and previously asserted
+    OptimizationHints as a default that must survive; after this fix the
+    expected defaults are MediaRouter and DialMediaRouteProvider only.
+    """
+    from crawl4ai.browser_manager import BrowserManager, ManagedBrowser
+
+    for light_mode in (False, True):
+        config = BrowserConfig(headless=True, light_mode=light_mode)
+        for flags in (
+            ManagedBrowser.build_browser_flags(config),
+            BrowserManager(browser_config=config)._build_browser_args()["args"],
+        ):
+            names = _disable_feature_names(flags)
+            assert "OptimizationHints" not in names, (
+                f"light_mode={light_mode}: OptimizationHints must not be disabled"
+            )
+            for expected in ("MediaRouter", "DialMediaRouteProvider"):
+                assert expected in names, (
+                    f"light_mode={light_mode} lost {expected}"
+                )
+
+
 # ---------------------------------------------------------------------------
 # Viewport configuration
 # ---------------------------------------------------------------------------

tests/unit/test_browser_disable_features.py

@@ -0,0 +1,59 @@
+"""Issue #2239: OptimizationHints must not appear in built --disable-features.
+
+Chrome-for-Testing 151+ SEGV_ACCERRs under --headless=new on macOS arm64 when
+OptimizationHints is disabled. MediaRouter and DialMediaRouteProvider stay.
+
+These are flag-construction checks only — no browser or network required.
+
+#2219 merges repeated --disable-features switches and currently expects
+OptimizationHints to survive that merge. After this change the surviving
+defaults are MediaRouter and DialMediaRouteProvider only.
+"""
+
+from crawl4ai import BrowserConfig
+from crawl4ai.browser_manager import BrowserManager, ManagedBrowser
+
+
+def _disable_feature_names(args):
+    """Every name listed in any --disable-features switch (not last-wins)."""
+    names = []
+    for arg in args:
+        if arg.startswith("--disable-features="):
+            names.extend(
+                name.strip()
+                for name in arg.split("=", 1)[1].split(",")
+                if name.strip()
+            )
+    return names
+
+
+def test_build_browser_flags_omits_optimization_hints():
+    config = BrowserConfig(headless=True)
+    names = _disable_feature_names(ManagedBrowser.build_browser_flags(config))
+    assert "OptimizationHints" not in names
+    assert "MediaRouter" in names
+    assert "DialMediaRouteProvider" in names
+
+
+def test_build_browser_args_omits_optimization_hints():
+    config = BrowserConfig(headless=True)
+    args = BrowserManager(browser_config=config)._build_browser_args()["args"]
+    names = _disable_feature_names(args)
+    assert "OptimizationHints" not in names
+    assert "MediaRouter" in names
+    assert "DialMediaRouteProvider" in names
+
+
+def test_light_mode_still_omits_optimization_hints():
+    """light_mode appends BROWSER_DISABLE_OPTIONS; OptimizationHints must
+    not reappear there either. Aligns with #2219's merge expectations:
+    MediaRouter / DialMediaRouteProvider remain the crawl4ai defaults."""
+    config = BrowserConfig(headless=True, light_mode=True)
+    for flags in (
+        ManagedBrowser.build_browser_flags(config),
+        BrowserManager(browser_config=config)._build_browser_args()["args"],
+    ):
+        names = _disable_feature_names(flags)
+        assert "OptimizationHints" not in names
+        assert "MediaRouter" in names
+        assert "DialMediaRouteProvider" in names