Maybe this one is also errorprone?

And... I don't think this way is a perfect fix, we should not always find the last /lua/, say I have a plugin have foo.nvim, I want to find this

-- ~/.local/share/lazy/foo.nvim/lua/foo/lua/bar.lua
pcall(require, 'foo.lua.bar')

A real world example: blink.cmp/lua/blink/cmp/fuzzy/lua/match_indices.lua

EDIT:
I didn't look into the lazy.nvim so all the above is just my guessing... (But I have a similar experience in neovim/neovim@c48cf18, hope it can be of helpful)

maybe a robust fix would look like this (if we can determine what the rtp is)

diff --git a/lua/lazy/core/plugin.lua b/lua/lazy/core/plugin.lua
index 37d1a8f..07c9f28 100644
--- a/lua/lazy/core/plugin.lua
+++ b/lua/lazy/core/plugin.lua
@@ -390,7 +390,7 @@ function M.find(path, opts)
     return
   end
   opts = opts or {}
-  local lua = path:find("/lua/", 1, true)
+  local lua = path:trim_rtp():find("/lua/", 1, true)
   if lua then
     local name = path:sub(1, lua - 1)
     local slash = name:reverse():find("/", 1, true)

Thanks @phanen!

I also think this is not the perfect fix. I can't answer your questions with confidence, so lets see what Folke has to say.

I am going to close this PR, as it breaks existing behavior.

Currently, imagining a local mod = require("blink.cmp.fuzzy.lua.match_indices"), the following holds true:

1. mod is correct
2. if blink.cmp is not yet present in rtp, it is added

With this PR:

1. mod is correct
2. if blink.cmp is not yet present in rtp, it is not added