Problem with prescient and swiper-query-replace on Emacs 28

[skyler544]

When using swiper-query-replace with prescient enabled, the prompt string is broken.

System info:

• Distro: Arch Linux
• Emacs: emacs-native-comp-git 28.0.50.146220-1

Expected behavior:

• Prompt string: Query replace [query] with:

Actual behavior:

• Prompt string: Query replace [a string of unrelated unicode characters like ȫⓝï][actual query] with:

The length of the string and the characters it is composed of seems different every time, but the actual query does show up at the end of the string.

Steps to reproduce:

• Vanilla Emacs, version 28.0.50
• Ivy, Swiper, and Prescient installed and enabled:
  • (require 'ivy)
  • (require 'ivy-prescient)
  • (require 'swiper)
  • M-x ivy-prescient-mode
  • M-x swiper
  • type something
  • M-q to open swiper-query-replace

EDIT: Added example screenshot for clarification

[okamsn]

This looks like it's related to character folding, but I don't know why that would affect the prompt.

[raxod502]

Yeah, so this is clearly related to character folding. In particular, you can run your query through char-fold-to-regexp and get exactly the string that is shown in the prompt (starting with a bunch of Unicode equivalents for c, then a bunch for o, and so on---because your query starts with co).

Apparently, swiper-query-replace uses some mechanism that goes through an interface advised by prescient.el. Not sure why that could be. It is quite bizarre.

[antoine-levitt]

FWIW, this also causes abo-abo/swiper#3017