From patchwork Thu Oct 11 19:46:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roger Strain X-Patchwork-Id: 10637373 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C05011508 for ; Thu, 11 Oct 2018 20:01:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A5DDE2C0DC for ; Thu, 11 Oct 2018 20:01:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9A5052C0F0; Thu, 11 Oct 2018 20:01:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 21D962C0E7 for ; Thu, 11 Oct 2018 20:01:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726196AbeJLDaL (ORCPT ); Thu, 11 Oct 2018 23:30:11 -0400 Received: from esg260-1.itc.swri.edu ([129.162.252.140]:54899 "EHLO esg260-1.itc.swri.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726079AbeJLDaL (ORCPT ); Thu, 11 Oct 2018 23:30:11 -0400 X-Greylist: delayed 921 seconds by postgrey-1.27 at vger.kernel.org; Thu, 11 Oct 2018 23:30:10 EDT Received: from rlstrain.wireless.dyn.datasys.swri.edu (virtual-FW-D10.netmgmt.swri.org [129.162.230.100]) by esg260-1.itc.swri.edu (8.16.0.22/8.16.0.22) with ESMTP id w9BJk5dJ013030 for ; Thu, 11 Oct 2018 14:46:06 -0500 From: Roger Strain To: git@vger.kernel.org Subject: [PATCH v2 4/4] subtree: improve decision on merges kept in split Date: Thu, 11 Oct 2018 14:46:05 -0500 Message-Id: <20181011194605.19518-5-rstrain@swri.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20180928183540.48968-1-roger.strain@swri.org> References: <20180928183540.48968-1-roger.strain@swri.org> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-10-11_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=inbound_policy_notspam policy=inbound_policy score=0 priorityscore=1501 malwarescore=0 suspectscore=4 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=651 adultscore=0 classifier=spam adjust=-40 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810110185 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "Strain, Roger L" When multiple identical parents are detected for a commit being considered for copying, explicitly check whether one is the common merge base between the commits. If so, the other commit can be used as the identical parent; if not, a merge must be performed to maintain history. In some situations two parents of a merge commit may appear to both have identical subtree content with each other and the current commit. However, those parents can potentially come from different commit graphs. Previous behavior would simply select one of the identical parents to serve as the replacement for this commit, based on the order in which they were processed. New behavior compares the merge base between the commits to determine if a new merge commit is necessary to maintain history despite the identical content. Signed-off-by: Strain, Roger L --- contrib/subtree/git-subtree.sh | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh index eef4199ae..7dd643998 100755 --- a/contrib/subtree/git-subtree.sh +++ b/contrib/subtree/git-subtree.sh @@ -541,6 +541,7 @@ copy_or_skip () { nonidentical= p= gotparents= + copycommit= for parent in $newparents do ptree=$(toptree_for_commit $parent) || exit $? @@ -548,7 +549,24 @@ copy_or_skip () { if test "$ptree" = "$tree" then # an identical parent could be used in place of this rev. - identical="$parent" + if test -n "$identical" + then + # if a previous identical parent was found, check whether + # one is already an ancestor of the other + mergebase=$(git merge-base $identical $parent) + if test "$identical" = "$mergebase" + then + # current identical commit is an ancestor of parent + identical="$parent" + elif test "$parent" != "$mergebase" + then + # no common history; commit must be copied + copycommit=1 + fi + else + # first identical parent detected + identical="$parent" + fi else nonidentical="$parent" fi @@ -571,7 +589,6 @@ copy_or_skip () { fi done - copycommit= if test -n "$identical" && test -n "$nonidentical" then extras=$(git rev-list --count $identical..$nonidentical)