private CompletionInitializationContext runContributorsBeforeCompletion(
      Editor editor, PsiFile psiFile, int invocationCount, Caret caret) {
    final Ref<CompletionContributor> current = Ref.create(null);
    CompletionInitializationContext context =
        new CompletionInitializationContext(
            editor, caret, psiFile, myCompletionType, invocationCount) {
          CompletionContributor dummyIdentifierChanger;

          @Override
          public void setDummyIdentifier(@NotNull String dummyIdentifier) {
            super.setDummyIdentifier(dummyIdentifier);

            if (dummyIdentifierChanger != null) {
              LOG.error(
                  "Changing the dummy identifier twice, already changed by "
                      + dummyIdentifierChanger);
            }
            dummyIdentifierChanger = current.get();
          }
        };
    List<CompletionContributor> contributors =
        CompletionContributor.forLanguage(context.getPositionLanguage());
    Project project = psiFile.getProject();
    List<CompletionContributor> filteredContributors =
        DumbService.getInstance(project).filterByDumbAwareness(contributors);
    for (final CompletionContributor contributor : filteredContributors) {
      current.set(contributor);
      contributor.beforeCompletion(context);
      CompletionAssertions.checkEditorValid(editor);
      assert !PsiDocumentManager.getInstance(project).isUncommited(editor.getDocument())
          : "Contributor " + contributor + " left the document uncommitted";
    }
    return context;
  }