gh-121160: Note that readline libraries using different history formats. (GH-121327)

This is not something we can do too much about, without help from the
underlying libraries.

diff --git a/Doc/library/readline.rst b/Doc/library/readline.rst
index 5658b93c81dc99a44a669a54e9d3b0b12a7effde..d03b71597130cfed66102c9469568fe578384912 100644 (file)
--- a/Doc/library/readline.rst
+++ b/Doc/library/readline.rst
@@ -45,6 +45,10 @@ Readline library in general.
     python:bind -v
     python:bind ^I rl_complete
 
+  Also note that different libraries may use different history file formats.
+  When switching the underlying library, existing history files may become
+  unusable.
+
 .. data:: backend
 
    The name of the underlying Readline library being used, either