Bug report

Bug description:

readline.set_completer_delims works fine with GNU readline, but not with libedit.

A quick example:

importreadlinereadline.set_completer_delims("\n")if"libedit"ingetattr(readline,"__doc__",""):readline.parse_and_bind("bind ^I rl_complete")else:readline.parse_and_bind("tab: complete")defcompleter(text,state):iftext=="$"andstate==0:return"$complete"returnNonereadline.set_completer(completer)input()# Type $ then <tab>

With GNU readline, it completes correctly, but with libedit, it can't - libedit still considers$ as a delimiter. You can confirm that by printing the text incompleter function.

The issue is inreadline.c:

readline.c writes torl_completer_word_break_characters, which works finesource.

However, libedit does not do the same thing, it usesrl_basic_word_break_charactersinstead:

if (rl_completion_word_break_hook!=NULL)breakchars= (*rl_completion_word_break_hook)();elsebreakchars=rl_basic_word_break_characters;

Thus, writing torl_completer_word_break_characters will not have any effect on libedit. The simplest way I can think of, is to write to bothrl_completer_word_break_characters andrl_basic_word_break_characters. They both exist in GNU readline and libedit, for slightly different purposes.

• GNU readline:
  • rl_completer_word_break_characters is the one that takes effect
  • rl_basic_word_break_characters just keeps a string as default value forrl_completer_word_break_characters
• libedit
  • rl_completer_word_break_characters is not used at all
  • rl_basic_word_break_characters is used for break words

From what I can observe, writing to both variables has no unexpected side effect, becauserl_basic_word_break_characters is not used on CPython with GNU readline.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux, macOS

Linked PRs

• gh-112105: Make completer delims work on libedit #112106
• [3.12] gh-112105: Make completer delims work on libedit (gh-112106) #112487
• [3.11] gh-112105: Make completer delims work on libedit (gh-112106) #112488