Search: don't trigger search on each cursor keys press ...

[ronso0]

instead, hook up to signals QCompleter::highlighted() and QLineEdit::selectionChanged() and accept the completer proposal if it's selection is changed (call slotTextChanged()).

This is an alternative to #11289

In my tests this works reliably because the signals are emitted like this:

• type some text the completer can pick up
• the completer appends the missing part and selectes it
• the QLineEdit emits (textChanged) and selectionChanged
• the QCompleter emits highlighted

[daschuer]

My first approach was similar, but it turns out that this was not robust, because the completer is just temporary.

I did a brief test and it confirms the issue. The completion is not searched after the window has lost and get the focus again. It is also lost if you toggle the library to full screen. In keeping track of the completion state in an extra bool feels fragile and connecting to a signal is a locking call.

This can be fixed by using our own completer.

Sure that this are all corner cases, but we have a working alternative solution already: #11289

[ronso0]

The issues you mention are caused by refreshing the "Enable auto-complete" state on each FocusIn event because -for now- the preferences have no connection to WSearchLineEdit and set a static bool instead. This reliefs us of having to reload the skin when the setting is toggled. Resetting the completer could be done only on demand, if the static bool doesn't match the current completer (valid pointer or nullptr).

Anyways, I'm not going to fight for this fix here, but eventually I'll revive this branch.

Gonna take a look at #11289 soonish.