address review: Discover.init takes a Library across all backends

Per review feedback, drop the `if (Discover == Windows)` comptime
branches in SharedGridSet and list_fonts by making every backend's
`init` take a Library and ignore it when unused. Call sites just do
`Discover.init(self.font_lib)` now.

Also adds a discovery test for the Windows backend that looks up
Arial and checks the returned face has the 'A' codepoint.

Co-authored-by: Claude <noreply@anthropic.com>

src/cli/list_fonts.zig

@@ -4,7 +4,6 @@ const ArenaAllocator = std.heap.ArenaAllocator;
 const Action = @import("ghostty.zig").Action;
 const args = @import("args.zig");
 const font = @import("../font/main.zig");
-const discovery = @import("../font/discovery.zig");
 
 const log = std.log.scoped(.list_fonts);
 
@@ -101,18 +100,12 @@ fn runArgs(alloc_gpa: Allocator, argsIter: anytype) !u8 {
     var families: std.ArrayList([]const u8) = .empty;
     var map: std.StringHashMap(std.ArrayListUnmanaged([]const u8)) = .init(alloc);
 
-    // Look up all available fonts. The Windows backend needs a FreeType
-    // library handle so it can open candidate font files while scanning
-    // the system/user font directories.
-    var font_lib = if (comptime font.Discover == discovery.Windows)
-        try font.Library.init(alloc)
-    else {};
-    defer if (comptime font.Discover == discovery.Windows) font_lib.deinit();
-
-    var disco = if (comptime font.Discover == discovery.Windows)
-        font.Discover.init(font_lib)
-    else
-        font.Discover.init();
+    // Look up all available fonts. The library is only used by backends
+    // that need it (the Windows backend opens candidate font files with
+    // FreeType); other backends ignore it.
+    var font_lib = try font.Library.init(alloc);
+    defer font_lib.deinit();
+    var disco = font.Discover.init(font_lib);
     defer disco.deinit();
     var disco_it = try disco.discover(alloc, .{
         .family = config.family,

src/font/SharedGridSet.zig

@@ -442,10 +442,7 @@ fn discover(self: *SharedGridSet) !?*Discover {
     // If we initialized, use it
     if (self.font_discover) |*v| return v;
 
-    self.font_discover = if (comptime Discover == discovery.Windows)
-        .init(self.font_lib)
-    else
-        .init();
+    self.font_discover = .init(self.font_lib);
     return &self.font_discover.?;
 }
 

src/font/discovery.zig

@@ -247,7 +247,8 @@ pub const Descriptor = struct {
 pub const Fontconfig = struct {
     fc_config: *fontconfig.Config,
 
-    pub fn init() Fontconfig {
+    pub fn init(lib: Library) Fontconfig {
+        _ = lib;
         // safe to call multiple times and concurrently
         _ = fontconfig.init();
         return .{ .fc_config = fontconfig.initLoadConfigAndFonts() };
@@ -338,7 +339,8 @@ pub const Fontconfig = struct {
 };
 
 pub const CoreText = struct {
-    pub fn init() CoreText {
+    pub fn init(lib: Library) CoreText {
+        _ = lib;
         // Required for the "interface" but does nothing for CoreText.
         return .{};
     }
@@ -1162,7 +1164,10 @@ test "fontconfig" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
-    var fc = Fontconfig.init();
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var fc = Fontconfig.init(lib);
     defer fc.deinit();
     var it = try fc.discover(alloc, .{ .family = "monospace", .size = 12 });
     defer it.deinit();
@@ -1174,7 +1179,10 @@ test "fontconfig codepoint" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
-    var fc = Fontconfig.init();
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var fc = Fontconfig.init(lib);
     defer fc.deinit();
     var it = try fc.discover(alloc, .{ .codepoint = 'A', .size = 12 });
     defer it.deinit();
@@ -1196,7 +1204,10 @@ test "coretext" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
-    var ct = CoreText.init();
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var ct = CoreText.init(lib);
     defer ct.deinit();
     var it = try ct.discover(alloc, .{ .family = "Monaco", .size = 12 });
     defer it.deinit();
@@ -1214,7 +1225,10 @@ test "coretext codepoint" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
-    var ct = CoreText.init();
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var ct = CoreText.init(lib);
     defer ct.deinit();
     var it = try ct.discover(alloc, .{ .codepoint = 'A', .size = 12 });
     defer it.deinit();
@@ -1243,7 +1257,10 @@ test "coretext sorting" {
     const testing = std.testing;
     const alloc = testing.allocator;
 
-    var ct = CoreText.init();
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var ct = CoreText.init(lib);
     defer ct.deinit();
 
     // We try to get a Regular, Italic, Bold, & Bold Italic version of SF Pro,
@@ -1309,3 +1326,24 @@ test "coretext sorting" {
         try testing.expectEqualStrings("SF Pro Bold Italic", name);
     }
 }
+
+test "windows" {
+    if (options.backend != .freetype_windows) return error.SkipZigTest;
+
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    var lib = try Library.init(alloc);
+    defer lib.deinit();
+
+    var win = Windows.init(lib);
+    defer win.deinit();
+
+    // Arial ships on every stock Windows install.
+    var it = try win.discover(alloc, .{ .family = "Arial", .size = 12 });
+    defer it.deinit();
+
+    var face = (try it.next()) orelse return error.TestFontNotFound;
+    defer face.deinit();
+    try testing.expect(face.hasCodepoint('A', null));
+}