From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 8DDD21F464 for ; Fri, 13 Dec 2019 18:59:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728794AbfLMS7C (ORCPT ); Fri, 13 Dec 2019 13:59:02 -0500 Received: from pb-smtp2.pobox.com ([64.147.108.71]:57442 "EHLO pb-smtp2.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728557AbfLMS7A (ORCPT ); Fri, 13 Dec 2019 13:59:00 -0500 Received: from pb-smtp2.pobox.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id 10D1318BEC; Fri, 13 Dec 2019 13:58:58 -0500 (EST) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:in-reply-to:references:date:message-id:mime-version :content-type; s=sasl; bh=Ppl7aJrAenHta3CBpei8o8rS7Ug=; b=YgJrXX Q57qgqnBD2lspEdxenJR24qsuS/CXcSLkGgol5tsZeTm2T4s7xlEedkNyqxU82La nnk1yFVA2rruS9NTbqRF8jkHEuDw7pD/BSa14GEmC/Wru38w2Jnub7nnhSzs5Yuk 8Sfg6KlrrB75X9pYpKsLSWYOTSjbuzgCnj6qE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:in-reply-to:references:date:message-id:mime-version :content-type; q=dns; s=sasl; b=KpjjtkVVOkZCyc1RL7mNo2qaIcCva+o9 WYcmhpmU/hQeoCdypECPeR4vJN92kJxJunYTFzWeyANldFYli9SkYoZY7XZdsD1g oIEiXGamGrtV5uFk8MzdVKM/zN5RMzUP3/F7iZbbl7WqyqkqTSaLKiUXOzQC+HAv tmLqmIKGIEo= Received: from pb-smtp2.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id 0898F18BEB; Fri, 13 Dec 2019 13:58:58 -0500 (EST) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [34.76.80.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp2.pobox.com (Postfix) with ESMTPSA id 6C80418BE9; Fri, 13 Dec 2019 13:58:57 -0500 (EST) (envelope-from junio@pobox.com) From: Junio C Hamano To: Maxim Kuvyrkov Cc: git@vger.kernel.org Subject: Re: [BUG] Git bisect extends bisecting range on repeated good/bad data In-Reply-To: <473FE927-FC11-46A0-8ABB-7A1FDC8C1A6C@linaro.org> (Maxim Kuvyrkov's message of "Fri, 13 Dec 2019 19:38:05 +0300") References: <473FE927-FC11-46A0-8ABB-7A1FDC8C1A6C@linaro.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) Date: Fri, 13 Dec 2019 10:58:56 -0800 Message-ID: MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 9DBBC62E-1DDA-11EA-B6A3-D1361DBA3BAF-77302942!pb-smtp2.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Maxim Kuvyrkov writes: > Git bisect may /extend/ bisection range on repeated good/bad data. Is this expected? It is not "repeated" that is an issue, but yes this is expected. The bisection works by finding a mid point to cut the graph into two pieces of roughly the same size, and the graph is defined by the set of good commits on the bottom (i.e. "we were told that all these good commits were good, so there is no point going back the history beyond any of them") and the single "bad" commit you gave the last. If you give 'bad' that is in the newer part of the history than the one that is already known to be bad, then you rewind that single "bad" commit, to force/allow the machinery to recompute the midpoint [*1*], and because the area to search would be wider when you do so, it is very much expected that you'd be offered to test more commits. [Footnote] *1* I said force/allow is because allowing the machinery to go back and recompute is a way to recover when you gave a "bad" earlier by mistake.