[PATCH 0/1] MR10201: dwrite: Add locales to locale list.

[Daniel Lehman (＠dlehman25)]

The Chinese version of the Noto Sans CJK font was being chosen despite being in Japanese locale.  Specifically, Noto Sans CJK SC was used for 0x5c06 instead of Noto Sans CJK JP.  The locale list for the system fallback collection was just the neutral locale.

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10201

[PATCH 1/1] dwrite: Add locales to locale list.

[Daniel Lehman]

From: Daniel Lehman <[e-mail]>

Existing helper font_fallback_get_locale returns neutral locale
if the exact name is not found.  This is ok when searching for
the font fallback, but shortcuts the adding of locale when
building the font fallback collection.
---
 dlls/dwrite/analyzer.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/dlls/dwrite/analyzer.c b/dlls/dwrite/analyzer.c
index 8548d8515fb..91ce6fd92be 100644
--- a/dlls/dwrite/analyzer.c
+++ b/dlls/dwrite/analyzer.c
@@ -531,6 +531,19 @@ static HRESULT fallback_locale_add_mapping(struct fallback_locale *locale, size_
     return S_OK;
 }
 
+static struct fallback_locale * font_fallback_get_locale_exact(const struct list *locales,
+        const WCHAR *locale_name)
+{
+    struct fallback_locale *locale;
+
+    LIST_FOR_EACH_ENTRY(locale, locales, struct fallback_locale, entry)
+    {
+        if (!wcsicmp(locale->name, locale_name)) return locale;
+    }
+
+    return NULL;
+}
+
 /* TODO: potentially needs improvement to consider partially matching locale names. */
 static struct fallback_locale * font_fallback_get_locale(const struct list *locales,
         const WCHAR *locale_name)
@@ -2764,7 +2777,7 @@ static struct fallback_locale * fallback_builder_add_locale(struct dwrite_fontfa
     struct fallback_locale *locale;
 
     if (!locale_name) locale_name = L"";
-    if ((locale = font_fallback_get_locale(&builder->data.locales, locale_name))) return locale;
+    if ((locale = font_fallback_get_locale_exact(&builder->data.locales, locale_name))) return locale;
     if (!(locale = calloc(1, sizeof(*locale)))) return NULL;
     lstrcpynW(locale->name, locale_name, ARRAY_SIZE(locale->name));
     list_add_tail(&builder->data.locales, &locale->entry);
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10201

[Nikolay Sivov (＠nsivov)]

What was the exact sequence of calls? Is this about system or custom fallback?

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10201#note_130703

[Daniel Lehman (＠dlehman25)]

> Is this about system or custom fallback?

system
> What was the exact sequence of calls?

this is a narrowed-ish down test:
https://gitlab.winehq.org/dlehman25/wine/-/compare/master...dwrite-locales-t...

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10201#note_130848

[Nikolay Sivov (＠nsivov)]

On Sat Feb 28 23:35:14 2026 +0000, Daniel Lehman wrote:
> > Is this about system or custom fallback?
> > system
> > What was the exact sequence of calls? 
> > this is a narrowed-ish down test:
> > https://gitlab.winehq.org/dlehman25/wine/-/compare/master...dwrite-locales-t...
> > I see, it's worse than I thought. This permissive matching prevents adding new entries. Thanks a lot for the test.

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10201#note_131069

[Nikolay Sivov (＠nsivov)]

Nikolay Sivov (@nsivov) commented about dlls/dwrite/analyzer.c:
> return S_OK;
>  }
>
> +static struct fallback_locale * font_fallback_get_locale_exact(const struct list *locales,
> +        const WCHAR *locale_name)
> +{
> +    struct fallback_locale *locale;
> +
> +    LIST_FOR_EACH_ENTRY(locale, locales, struct fallback_locale, entry)
> +    {
> +        if (!wcsicmp(locale->name, locale_name)) return locale;
> +    }
> +
> +    return NULL;
> +}

This is fine but we don't need to duplicate. Could you add a bool flag to the font_fallback_get_locale(), either 'use_neutral' or, an opposite to it, 'exact_match' to block second condition.

P.S. stdbool.h is already included and used, so "bool" is good for internal things.

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10201#note_131070