Mark Books: "Show marked books" dynamic menu causing problematic behaviour in plugins that call it

[ownedbycats]

Calibre 5.7 (x64)

Due to the changes in the "Show Marked Books (x)" menu entry, it can misbehave with plugins that attempt to call it. I can confirm this happens with two plugins:

1. Adding Show Marked Books to the Favourites Menu (https://www.mobileread.com/forums/showthread.php?t=183022) will cause it to become greyed out when the number of books change.

2. Action Chains (https://www.mobileread.com/forums/showthread.php?t=334974) has been having recurring problems with this entry causing the entire chain to fail when it's not found. See this for more information: https://www.mobileread.com/forums/showpost.php?p=4070964&postcount=137

Another thing to note: Although the Reading List plugin (https://www.mobileread.com/forums/showthread.php?t=134856) also has a menu entry "View Reading List (x)" that changes with the number of books, it doesn't have the same issue as Show Marked Books.

If there's a way to fix this, it'd be appreciated. Thank you!

[ownedbycats (ownedbycats)]

Further inspection: Reading List appears to use a static menu entry ("View List: List Name") in the Favourites menu, and this also appears in Action Chains.

[ownedbycats (ownedbycats)]

Additional information: kiwidude's plugins all use a constant attribute called "favourites_menu_unique_name" for the dynamically-changing menu entries:
https://www.mobileread.com/forums/showthread.php?p=2129353#post2129353

[Kovid Goyal (kovid)]

The action changes its text based on how many marked books are present
just before the menu is displayed, that is not going to change. If a
plugin wants to refer to it, it can either match the text more carefully
taking into account both forms or create a wrapper action that is
connected to the actual action with fixed text.

 status invalid