feat: Mark shiny theme stylesheets with data-shiny-theme

And store theme name if `ui.Theme()` is used

Author: gadenbuie

shiny/ui/_html_deps_external.py

@@ -26,24 +26,50 @@
 ThemeProvider = Union[Tagifiable, HTMLDependency, List[HTMLDependency]]
 
 
+def mark_shiny_theme_stylesheets(dep: HTMLDependency, name: str = "") -> HTMLDependency:
+    if not isinstance(dep, HTMLDependency):
+        raise ValueError(
+            "Expected an HTMLDependency, but received a value with type "
+            f"{type(dep)}."
+        )
+
+    if len(dep.stylesheet) > 0:
+        for sheet in dep.stylesheet:
+            sheet["data-shiny-theme"] = name  # type: ignore
+
+    return dep
+
+
 def shiny_page_theme_deps(theme: str | Path | Theme | ThemeProvider | None) -> TagList:
     deps_bootstrap = bootstrap_deps(include_css=theme is None)
 
     if theme is None:
         deps_theme = None
     elif isinstance(theme, Theme):
-        deps_theme = theme._html_dependency()
+        deps_theme = mark_shiny_theme_stylesheets(
+            theme._html_dependency(),
+            name=theme.name or theme._preset,
+        )
     elif isinstance(theme, str) and theme.startswith(("http", "//")):
-        deps_theme = head_content(link(rel="stylesheet", href=theme, type="text/css"))
+        theme_link = link(
+            rel="stylesheet", href=theme, type="text/css", data_shiny_theme=""
+        )
+        deps_theme = head_content(theme_link)
     elif isinstance(theme, (str, Path)):
         check_path(theme)
-        deps_theme = head_content(include_css(theme))
-    elif isinstance(theme, Tagifiable) or isinstance(theme, HTMLDependency):
-        deps_theme = theme
+        theme_link = include_css(theme)
+        theme_link.attrs["data-shiny-theme"] = ""
+        deps_theme = head_content(theme_link)
+    elif isinstance(theme, HTMLDependency):
+        deps_theme = mark_shiny_theme_stylesheets(theme)
     elif isinstance(theme, list) and all(
         [isinstance(dep, HTMLDependency) for dep in theme]
     ):
-        deps_theme = theme
+        deps_theme = [mark_shiny_theme_stylesheets(t) for t in theme]
+    elif isinstance(theme, Tagifiable):
+        deps_theme = TagList(theme.tagify())
+        for dep in deps_theme.get_dependencies():
+            mark_shiny_theme_stylesheets(dep)
     else:
         raise ValueError(
             "Invalid `theme`. "

tests/pytest/test_theme.py

@@ -166,7 +166,7 @@ def _page_sidebar(*args, **kwargs) -> Tag:  # type: ignore
 )
 @pytest.mark.parametrize(
     "theme",
-    [None, Theme("shiny"), Theme("bootstrap"), Theme("sketchy")],
+    [None, Theme("shiny"), Theme("bootstrap", name="default"), Theme("sketchy")],
 )
 def test_page_theme_wins(page_fn: Callable[..., Tag], theme: Theme | None):
     ui = page_fn(
@@ -189,7 +189,9 @@ def test_page_theme_wins(page_fn: Callable[..., Tag], theme: Theme | None):
     ]
 
     for dep in deps:
-        if dep.name in no_css:
+        if theme is not None and dep.name.startswith("shiny-theme"):
+            assert dep.stylesheet[0]["data-shiny-theme"] == theme.name or theme._preset  # type: ignore
+        elif dep.name in no_css:
             # These components should have CSS suppressed by the page-level
             # dependency from shiny_page_theme_deps(). If this test fails, it means
             # that our assumptions about how htmltools' dependency resolution works