fix: Can't use null !default trick for Bootstrap core vars like $primary, $secondary, etc.

Author: gadenbuie

shiny/ui/_theme_brand.py

@@ -262,9 +262,19 @@ def _prepare_color_vars(
         palette_defaults_dict: dict[str, str | float | int | bool | None] = {}
         palette_css_vars: list[str] = []
 
-        # Map values in colors to their Sass variable counterparts
         for thm_name, thm_color in brand.color.to_dict(include="theme").items():
-            defaults_dict[f"brand_color_{thm_name}"] = thm_color
+            # Create brand Sass variables and set related Bootstrap Sass vars
+            # brand.color.primary = "#007bff"
+            # ==> $brand_color_primary: #007bff !default;
+            # ==> $primary: $brand_color_primary !default;
+
+            brand_color_var = f"brand_color_{thm_name}"
+            defaults_dict[brand_color_var] = thm_color
+            # Currently, brand.color fields are directly named after Bootstrap vars. If
+            # that changes, we'd need to use a map here. These values can't be set to
+            # `null !default` because they're used by maps in the Bootstrap mixins layer
+            # and cause errors if a color is `null` rather than non-existent.
+            defaults_dict[thm_name] = f"${brand_color_var}"
 
         brand_color_palette = brand.color.to_dict(include="palette")
 

shiny/www/py-shiny/brand/_brand-yml.scss

@@ -72,18 +72,10 @@ $body-color: $brand_color_foreground !default;
 $body-bg-dark: $brand_color_foreground !default;
 $body-bg: $brand_color_background !default;
 $body-color-dark: $brand_color_background !default;
-$primary: $brand_color_primary !default;
-$secondary: $brand_color_secondary !default;
 $body-secondary-color: $brand_color_secondary !default;
 $body-secondary: $brand_color_secondary !default;
 $body-tertiary-color: $brand_color_tertiary !default;
 $body-tertiary: $brand_color_tertiary !default;
-$success: $brand_color_success !default;
-$info: $brand_color_info !default;
-$warning: $brand_color_warning !default;
-$danger: $brand_color_danger !default;
-$light: $brand_color_light !default;
-$dark: $brand_color_dark !default;
 
 //*-- brand.typography --*//
 // brand.typography.base