Bug 295962 – [GTK] inconsistent font selection, mixing serif and san-serif fonts

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Fujii Hironori]

Created attachment 476012 [details]
screenshot

I'm using the latest Epiphany TP (2025-07-14) and Fedora 42.
It has a problem of inconsistent font selection, mixing serif and san-serif fonts at <https://www.sankei.com/>.

[Fujii Hironori]

Created attachment 476013 [details]
reduced content

[Fujii Hironori]

Created attachment 476014 [details]
screenshot of www.goo.ne.jp

https://www.goo.ne.jp/ also has this issue.

[Fujii Hironori]

Comment on attachment 476013 [details]
reduced content

This reduced content is no longer reproducible for me even though I created this today and I didn't change any fonts settings on my system.

[Fujii Hironori]

Created attachment 477028 [details]
reduced content

[Fujii Hironori]

This is still reproducible with Epiphany Canary (WebKitGTK 301039@main) on my Fedora Linux.

[Fujii Hironori]

Created attachment 478206 [details]
reduced content 2

[Fujii Hironori]

SystemFallbackFontCache caches the system fallback font without checking weight.

diff --git a/Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp b/Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp
index cb417a199164..f93b8f24d0be 100644
--- a/Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp
+++ b/Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp
@@ -55,6 +55,7 @@ SystemFallbackFontCache* SystemFallbackFontCache::forCurrentThreadIfExists()
 
 RefPtr<Font> SystemFallbackFontCache::systemFallbackFontForCharacterCluster(const Font* font, StringView characterCluster, const FontDescription& description, ResolvedEmojiPolicy resolvedEmojiPolicy, IsForPlatformFont isForPlatformFont)
 {
+    m_characterFallbackMaps.clear();
     auto fontAddResult = m_characterFallbackMaps.add(font, CharacterFallbackMap());
 
     auto key = CharacterFallbackMapKey { description.computedLocale(), characterCluster.toString(), isForPlatformFont != IsForPlatformFont::No, resolvedEmojiPolicy };

[Fujii Hironori]

Mac port doesn't take the weight into account for looking for a system fallback font.
https://github.com/WebKit/WebKit/blob/7e125e789b46fa178bf3f15cd89cd1ad52670cb7/Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp#L796

[Fujii Hironori]

Pull request: https://github.com/WebKit/WebKit/pull/57646

[EWS]

Committed 307565@main (ce075d61e972): <https://commits.webkit.org/307565@main>

Reviewed commits have been landed. Closing PR #57646 and removing active labels.