Ping.

I've found a way to reproduce a related issue:

$ mkdir ~/test
$ balooctl config add includeFolders ~/test
$ balooctl stop
<make some changes with ~/test, i.e. add a tag>
$ balooctl start

This prints an error:

replace called with invalid arguments, docId: <docid> url: "~/test/"

The problem is the same: DocumentUrlDB returns a path without trailing slash, but FilteredDirIterator returns a path with one.
WriteTransaction thinks the path has changed, tries to replace it, calls DocumentUrlDB::replace, which fails because it doesn't want to work with path which has trailing slash.

In general, it's not a serious issue: we have problems only for folders that are inside includeFolders. If such folder wasn't renamed, then we don't care about DocUrlDB::replace failure anyway.
If it was renamed, most likely it's not inside includeFolders anymore. However, we can do something like

$ mkdir ~/test1
$ mkdir ~/test2
$ balooctl config add includeFolders ~/test{1,2}
$ touch ~/test1/somefile
$ balooctl stop
$ rm -rf ~/test2
$ mv ~/test2 ~/test1
$ balooctl start

the rename then gets silently ignored (file somefile doesn't pop up in searches; if we do balooshow -x <docid>, it returns an invalid path).

Not entirely sure, but bug 409257 might be caused by that (at least in my case, it looked the same).

Ping!

Apparently, it does fix bug 409257, which is pretty serious one (db corruption, after all).

In D21427#494010, @poboiko wrote:

Ping!

Apparently, it does fix bug 409257, which is pretty serious one (db corruption, after all).

The DB corruption is already fixed in KF5.60.

In D21427#494174, @bruns wrote:

In D21427#494010, @poboiko wrote:

Ping!

Apparently, it does fix bug 409257, which is pretty serious one (db corruption, after all).

The DB corruption is already fixed in KF5.60.

I saw it in master and was wondering if it ended up in 5.60 (and whether it's still possible to corrupt it in any other way).

OK, DB corruption apart, I believe this patch is still relevant - we rely on paths not having trailing slash in different parts of the code anyways. And it clearly doesn't work as expected.