Source labels and prop source lists redo the full lookup on each call

hello,
we have different independent changes here :
(a) changes about the labels
(b) changes about caching context matches.

and the numbers you have provided do not give details about the gain of each part.

for (a), this proposition may deserve a more generic and elegant fix instead of patching manually different sources. Indeed,
SourcePluginBase::label(TRUE) needs one label, but builds every choice through getChoices() to get it. Every source that implements SourceWithChoicesInterface pays for that.

i proposed a Generic version. label() stays the only place that does the $with_context check and the fallback. It asks one overridable method for the chosen label, something like that :

// SourcePluginBase
public function label(bool $with_context = FALSE): string {
  if ($with_context && $this instanceof SourceWithChoicesInterface) {
    $choice_id = $this->getChoice($this->settings);
    $label = $choice_id ? $this->getChoiceLabel($choice_id) : NULL;
    if ($label !== NULL) {
      return $label;
    }
  }
  return /* plugin label, unchanged */;
}

protected function getChoiceLabel(string $choice_id): ?string {
  $label = $this->getChoices()[$choice_id]['label'] ?? NULL;
  return $label === NULL ? NULL : (string) $label;
}

ComponentSource and DerivableContextSourceBase would override only getChoiceLabel(), with their one-choice lookup. LayoutSource could do the same later.

(b) i opened a new separate issue #3631243: Improve static caches : one mechanism, emptied with the definitions to tackle static caches improvement, i will personally address that. in the meantime, could you remove that part from the current proposition and stick to the label part.

thank you