Merge pull request #1443 from mitchellh/mode-2027

config: grapheme-width-method sets mode 2027

src/config/Config.zig

@@ -208,7 +208,7 @@ const c = @cImport({
 /// reset, this configuration will be used again.
 ///
 /// This configuration can be changed at runtime but will not affect existing
-/// printed cells. Only new cells will use the new configuration.
+/// terminals. Only new terminals will use the new configuration.
 @"grapheme-width-method": GraphemeWidthMethod = .unicode,
 
 /// A named theme to use. The available themes are currently hardcoded to the

src/terminal/Terminal.zig

@@ -119,9 +119,6 @@ flags: packed struct {
     /// then we want to capture the shift key for the mouse protocol
     /// if the configuration allows it.
     mouse_shift_capture: enum { null, false, true } = .null,
-
-    /// If true, we perform grapheme clustering even if mode 2027 is disabled.
-    default_grapheme_cluster: bool = false,
 } = .{},
 
 /// The event types that can be reported for mouse-related activities.
@@ -746,10 +743,7 @@ pub fn print(self: *Terminal, c: u21) !void {
     // This is MUCH slower than the normal path so the conditional below is
     // purposely ordered in least-likely to most-likely so we can drop out
     // as quickly as possible.
-    if (c > 255 and
+    if (c > 255 and self.modes.get(.grapheme_cluster) and self.screen.cursor.x > 0) grapheme: {
-        (self.modes.get(.grapheme_cluster) or self.flags.default_grapheme_cluster) and
-        self.screen.cursor.x > 0)
-    grapheme: {
         const row = self.screen.getRow(.{ .active = self.screen.cursor.y });
 
         // We need the previous cell to determine if we're at a grapheme
@@ -891,9 +885,7 @@ pub fn print(self: *Terminal, c: u21) !void {
         // If we have grapheme clustering enabled, we don't blindly attach
         // any zero width character to our cells and we instead just ignore
         // it.
-        if (self.modes.get(.grapheme_cluster) or
+        if (self.modes.get(.grapheme_cluster)) return;
-            self.flags.default_grapheme_cluster)
-            return;
 
         // If we're at cell zero, then this is malformed data and we don't
         // print anything or even store this. Zero-width characters are ALWAYS

src/termio/Exec.zig

@@ -135,7 +135,13 @@ pub fn init(alloc: Allocator, opts: termio.Options) !Exec {
     errdefer term.deinit(alloc);
     term.default_palette = opts.config.palette;
     term.color_palette.colors = opts.config.palette;
-    term.flags.default_grapheme_cluster = opts.config.grapheme_width_method == .unicode;
+
+    // Setup our initial grapheme cluster support if enabled. We use a
+    // switch to ensure we get a compiler error if more cases are added.
+    switch (opts.config.grapheme_width_method) {
+        .unicode => term.modes.set(.grapheme_cluster, true),
+        .wcswidth => {},
+    }
 
     // Set the image size limits
     try term.screen.kitty_images.setLimit(alloc, opts.config.image_storage_limit);
@@ -373,8 +379,6 @@ pub fn changeConfig(self: *Exec, config: *DerivedConfig) !void {
     //   - command, working-directory: we never restart the underlying
     //   process so we don't care or need to know about these.
 
-    self.terminal.flags.default_grapheme_cluster = config.grapheme_width_method == .unicode;
-
     // Update the default palette. Note this will only apply to new colors drawn
     // since we decode all palette colors to RGB on usage.
     self.terminal.default_palette = config.palette;