That one is pretty tricky. The only way that I can think of is to delay indentation until the first character is typed, and not to indent if it is a space or tab. 

From: Serhiy Storchaka
Sent: Wednesday, February 1, 2017 2:39 PM
To: xoviat@gmail.com
Subject: [issue29339] Interactive: Move to same indentation level as previousline

Serhiy Storchaka added the comment:

Any autoindetation breaks pasting from the clipboard since there is no way to distinguish characters entered from the keyboard from characters pasted from the clipboard. In IDLE or other visual shell we can add a special menu entry and hotkeys for pasting from clipboards without autoindenting, but in a REPL in text terminal this is not possible.

IPython3 solved this issue by adding special magic functions, but this is not a way for CPython.

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nosy: +serhiy.storchaka

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Python tracker <report@bugs.python.org>
<http://bugs.python.org/issue29339>
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