bug#10113: 24.0.91; Isearch & `M-e'

[Juri Linkov <juri@jurta.org>]

> Because, removing the final "R" via minibuffer should be equivalent to
> do it directly by typing DEL (just after the "R").

Actually `M-e DEL RET' is not equivalent to `DEL'.
It is equivalent to `C-M-w' (`isearch-del-char').

> In this second case, my reasoning is analogous: Changing the final "R"
> with a "r" via minibuffer should be equivalent to doing that directly
> (typing "DEL r" just after the "R").

`M-e DEL r RET' is not equivalent to `DEL r'.
It is equivalent to `C-M-w r'.

> IOW, the case-sensitivity of the Isearch, when it's determined
> _automatically_ (not by typing `M-c'),

WRT automatic changing of case-sensitivity after entering
an upper-case letter, this is a traditional behavior that
you can disable by customizing `search-upper-case' to nil.

> should be revised after editing the search string in the minibuffer,
> to produce a result consistent with the principle I said before.

This is unrelated to `isearch-edit-string'.  You'll get the same result
when you type `C-a C-s b u f f e R C-M-w r'.