Error during redisplay: (eval (breadcrumb--header-line)) signaled (args-out-of-range 0 1)

[jcs090218]

Error during redisplay: (eval (breadcrumb--header-line)) signaled (args-out-of-range 0 1)

[joaotavora]

Reproduced. Maybe I could do something about this, but you should first ask svelte-modes developers why the imenu structure
they they produce in your example is (("" . 20)), i.e. why are there menu elements with empty strings.

I.e. if I do something about this, it will not change the outcome dramatically: the error will disappear but there will be nonsensical imenu information

[leafOfTree]

Hi, I'm from svelte-mode and not quite sure about the imenu structure. svelte-mode is based on mhtml-mode.
Both have the same issue.

It seems that the menu is using <h1> tag text content. The error occurs when it's empty. Otherwise, it will show its content.

    <section>
      <h1>
        hello
        <span class="welcome">
        </span>
      </h1>
      <Counter />
    </section>

For this case, I think we can ignore the error as HTML tags may have empty text content and result in an empty menu.

[joaotavora]

For this case, I think we can ignore the error as HTML tags may have empty text content and result in an empty menu.

Sure, I guess. Breadcrumb operates on the same information that M-x imenu does. Major mode authors setting up imenu-create-index-function or authors deriving from such modes such always test that M-x imenu does reasonable things.

If it doesn't, neither will breadcrumb. Imenu is a flimsy and hacked-together piece of utility, unfortunately, but it's the most widespread one.

If the problem lies deeper in mhtml-mode ,then it should probably be fixed there.

[leafOfTree]

I agree the major mode (actually it's sgml-mode ) should provide correct and useful imenu info. But I'm not sure where to find the sgml-mode maintainer.

By the way, it seems to stop working if there is an incorrect imenu. The breadcrumb bar becomes empty with: Error during redisplay: (eval (breadcrumb--header-line) t) signaled (args-out-of-range 0 1)

Is it possible that, on the other side, breadcrumb can handle the error gracefully, like just ignoring the error?

[joaotavora]

But I'm not sure where to find the sgml-mode maintainer.

Isn't it a part of Emacs? Report it to [email protected].

Is it possible that, on the other side, breadcrumb can handle the error gracefully, like just ignoring the error?

Yes, as I said something like that can be done. But making breadcrumb.el ignoring this particular error is somewhat tricky, so if someone has patch and can test through some edge cases (like an imenu that does have some invalid entries and some valid ones), it would be ideal.