Breadcrumbs disappear until cache clear for one language

This duplicates adding the route and url.path context. However, without this breadcrumbs still disappear occassionally.

This comment gives me an uncomfortable feeling, it sounds like a hack to me. Do we understand why the bug occurs?

It would be beneficial to have at least the steps to reproduce the problem, i.e. which Drupal setup. Some suggestion: Interface translation y/n, content translation y/n, menu translatable y/n, menu-items translatable y/n, url alias differs per language y/n, active trail differs per language y/n

I don't experience the problem in my set-up (yet), but I do have collected the cache contexts of the breadcrumb block (used renderviz module):

• "languages:language_content",
• "languages:language_interface",
• "route.menu_active_trails:main",
• "url.path",
• "user.permissions"

@nicxvan do you know the steps to "how to reproduce" that?

I have a similar issue that that breadcrumb doesn't appear in some languages in production, but is working fine locally. I have a guess that is related to memcached. But I'm not really sure. I'm curious because seems to be similar

I also experienced this issue, little different. All of a sudden menu breadcrumb stopped working. Finally found out that it was related to facet pretty paths and Search API. There was a node that had the same URL Alias as a search display. As soon as I renamed the node and cleared the cache, menu breadcrumb was working again.

It seemed that facet pretty paths somehow added its query parameters to all node requests and thus menu breadcrumb did not find itself responsible anymore (applies method) for any nodes. Strange enough that this kills all node breadcrumbs ...

I am also experiencing something similar, but in case I identified that the breadcrumb breaks everytime I visit a node.

Example:
-- Visit custom route, breadcrumb show
-- Visit node
-- Visit same custom route, breadcrumb disappears

And I need to flush the cache in order for the breadcrumb to reappear on the custom route.

EDIT: was the fault of a custom preprocess that was emptying the whole content including the cache tags.

There is a Menu Breadcrumb fix related to route parameter matching in #3392139: Wrong breadcrumb due to route alterations which might be of interest. Thanks for linking #2875276: Breadcrumbs disappears when starting with front-page after cache rebuild (for anonymous user). as well Nic.

I faced this issue too but a bit different as it was not language related but user related.
I think I found steps to reproduce and the underlying cause of this.

Steps to reproduce

1. Create three pages: /test1, /test2 and /test3 (paths are important)
2. Add two pages to the main menu: [root] > test2 > test3 (test1 is not in the menu)
3. Clear all caches
4. Access /test1 - expected breadcrumb: [Home]
5. Access /test2 - expected breadcrumb: [Home] > test2
6. Access /test3 - expected breadcrumb: [Home] > test2 > test3

Current results:

• Breadcrumb for /test1: [Home]
• Breadcrumb for /test2: [Home]
• Breadcrumb for /test3: [Home]

Note: [Home] only shows if breadcrumbs are configured that way. If they are not, the breadcrumb just disappear.

Why is that?

This seems to be related to the way Core caches its own breadcrumbs. The way Core builds its breadcrumbs only needs to know the parent path of the current page. That's why they declare url.path.parent as a cache context and not url.path like Menu Breadcrumb does. What happens is that if you first load a page where the breadcrumb is not managed by Menu Breadcrumb, then the breadcrumb block will be held in cache for every other pages sharing the same parent path. While using url.path.parent is a nice optimization in the Core's breadcrumbs management, it's what's causing our issue here.

As you can see in !22, the fix is quite simple and I believe it would also fix the original issue explained in the IS.

I was tasked with debugging some quirky breadcrumb issues this week, and I wasn't able to reliably replicate the problem until I came across the details in #15. With that info, I was able to get my local site into the state of having invalid breadcrumbs and can confirm that the fix in !22 has resolved my issues.

@duaelfr: Thanks for the patch and the detailed explanation. The timing of cache clears, our menu structure, and the order of pages visited meant that we hadn't been seeing this outside of production, but what you've described aligns with what I'm seeing (not related to language).

Adding a patch of the current MR for testing purposes

Good morning! Just chiming in here, this fixed an issue we were dealing with where the breadcrumb was being driven by the assignment to a Group. Alias was derived from the group path, but breadcrumb was being cached. Thanks everyone!

Thanks all! And thanks @nicxvan for the nudge to land this.

Looks good.