validate html_static_path on config-inited

sphinx/builders/html.py

@@ -783,9 +783,6 @@ def copy_static_files(self) -> None:
             excluded = Matcher(self.config.exclude_patterns + ["**/.*"])
             for static_path in self.config.html_static_path:
                 entry = path.join(self.confdir, static_path)
-                if not path.exists(entry):
-                    logger.warning(__('html_static_path entry %r does not exist'), entry)
-                    continue
                 copy_asset(entry, path.join(self.outdir, '_static'), excluded,
                            context=ctx, renderer=self.templates)
             # copy logo and favicon files if not already in static path
@@ -1166,6 +1163,14 @@ def validate_math_renderer(app: Sphinx) -> None:
         raise ConfigError(__('Unknown math_renderer %r is given.') % name)
 
 
+def validate_html_static_path(app: Sphinx, config: Config) -> None:
+    """Check html_static_paths setting."""
+    for entry in config.html_static_path[:]:
+        if not path.exists(path.join(app.confdir, entry)):
+            logger.warning(__('html_static_path entry %r does not exist'), entry)
+            config.html_static_path.remove(entry)
+
+
 # for compatibility
 import sphinx.builders.dirhtml  # NOQA
 import sphinx.builders.singlehtml  # NOQA
@@ -1221,6 +1226,7 @@ def setup(app: Sphinx) -> Dict[str, Any]:
     # event handlers
     app.connect('config-inited', convert_html_css_files)
     app.connect('config-inited', convert_html_js_files)
+    app.connect('config-inited', validate_html_static_path)
     app.connect('builder-inited', validate_math_renderer)
     app.connect('html-page-context', setup_js_tag_helper)