From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3FB311182 for ; Thu, 16 May 2024 05:08:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715836125; cv=none; b=aTvehXyEWuCzjY3L5OQRMzC3qLP02PeUe+Lr/vXJ/on5vNYqn5Dd8nhcIdAzrwvi6yLqjZiRoikiz8ucRudJYwMu7hMTvb5oGKNzL9M8n0Jw8PEL/C74k+NNdV3VP8rk/ggY9gsLNunJTe0ub03Yg23jXEbYnRNk80AIpqej7/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715836125; c=relaxed/simple; bh=9Go0fcVASNJ2p48AqWz0BdrZ0A70MNgXwK5yLQ2ebZY=; h=Message-Id:From:Date:Subject:Content-Type:MIME-Version:To:Cc; b=JlgCGcyWsuReO+vkWwBVYspAuklwKa5ee6ztmbEZ5NQVWVjHYT/7yBA+IIvSI3hlTR0lst/CAud2nasLF0ygJwljHZ9N1mxtRumLMH3vJ9PpIOiwybEcNaCZYvrbW6yOu82LboGzcptLlTjFhjc82HYPcFB/pTiQDpyz0E2A2ZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=mjNNXbte; arc=none smtp.client-ip=209.85.128.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mjNNXbte" Received: by mail-wm1-f54.google.com with SMTP id 5b1f17b1804b1-4202ca70287so455185e9.3 for ; Wed, 15 May 2024 22:08:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1715836122; x=1716440922; darn=vger.kernel.org; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :message-id:from:to:cc:subject:date:message-id:reply-to; bh=nMdBO7SmPY8MBWcqk/BhjRGLLxh8cJwMCx5UYVpcWiA=; b=mjNNXbtehfckQ9OEnfA/MXsymJ4BqrueoPLggd4jMlK2oI/jgx3tJHJUHPzTp0IBP8 oYP2mZ8ZLo1NiKTyyW44+ijMvFhEJpzZAPeW27mxtrjRwVucZRm5nIoaslqrFzQZaDCe 8zR8+uLvKu7ZHDRaiFffh4jtHB25hzLzibnH2bSKemcMgJHcgF9MGx+OdAQrOmXM1RFD rH7OUTzxiOuybsLs3HtqpPatCMynYVjKQ16HaRcvf1xEhhrwqy9/bHReYr9dLOaWN3jx Hhsiw76kQn6AJioxdOKG9s08zJ2Uw97G0Cw90OAezc+DQoZpX6Dn7TD47ZOyljytEgHG OpBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715836122; x=1716440922; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=nMdBO7SmPY8MBWcqk/BhjRGLLxh8cJwMCx5UYVpcWiA=; b=D+D2aJJ7AOj+DgQOQdVOVEacKIUnz8p+npK+zrNrQkLkaG99gzwqKAXAm7iF0rhg05 dLjSXTW8mhEpz7aWDxG4lJKacfRVB6b6MQNvvj24cJ/Let8rWa3yOCMJBkjAw89XneAm trvdFVwi17Z+adZS5EfePnbkWGrOd7gdY3/RhSMz605sTB44f6FjSMk+MCo522IdXQVd H4bnWKYleKorNwyiPENj3zR5DmCv5t0JnY4qrJi0SXX6UOo+ebhGRAN6wDkArD5oPPKB a/BsUMkdfR+Hl+IWzvvfIe4QWs57ceJOlIhHo38w7g8Sfuc9X9b/2Cnimc++E7jnFHSK fGjw== X-Gm-Message-State: AOJu0YxVtjixb1wRnMlwnGXQEBF4VJbfzANDcpGMA+X5OQao0nf66ImV ZNa/0sp6tBMBzGTEwXlaWKsW7JyZzo2VQkWFAKoxKWxo1+KbtLfxg5ZeTg== X-Google-Smtp-Source: AGHT+IENczOsDKuMO0GyR2rVK5IcjVCqVeyLo1S+Mim2EskQ8eoJC6gHc/K/61lbxWNMsoNx48ac8A== X-Received: by 2002:adf:f590:0:b0:34c:b86a:794c with SMTP id ffacd0b85a97d-3504a96b845mr16818567f8f.70.1715836121837; Wed, 15 May 2024 22:08:41 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3502b8a7826sm17859133f8f.52.2024.05.15.22.08.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 May 2024 22:08:41 -0700 (PDT) Message-Id: From: "Kyle Zhao via GitGitGadget" Date: Thu, 16 May 2024 05:08:40 +0000 Subject: [PATCH] merge: avoid write merge state when unable to write index Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: git@vger.kernel.org Cc: Kyle Zhao , Kyle Zhao From: Kyle Zhao Currently, when index.lock exists, if a merge occurs, the merge state will be written and the index will be unchanged. If the user exec "git commit" instead of "git merge --abort" after this, the commit will be successful and all modifications from the source branch will be lost. Signed-off-by: Kyle Zhao --- merge: avoid write merge state when unable to write index In some of our monorepos, code is sometimes lost after merging. After investigation, we discovered the problem. This happens if we perform "git pull" or "git merge" when another git process is writing to the index, especially in a monorepo (because its index will be larger). How to reproduce: git init demo cd demo touch 1.txt && git add . && git commit -m "1" git checkout -b source-branch touch 2.txt && git add . && git commit -m "2" echo "1" >> 1.txt && git add . && git commit -m "3" touch .git/index.lock git merge source-branch rm .git/index.lock git commit -m "4" Then the modifications from the source branch are lost. Regards, Kyle cc: Elijah Newren newren@gmail.com cc: Ævar Arnfjörð Bjarmason avarab@gmail.com cc: Junio C Hamano gitster@pobox.com Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1731%2Fkeyu98%2Fkz%2Ffix-merge-when-index-lock-exists-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1731/keyu98/kz/fix-merge-when-index-lock-exists-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/1731 builtin/merge.c | 6 ++++-- t/t7600-merge.sh | 10 ++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/builtin/merge.c b/builtin/merge.c index 6a6d3798858..80e3438be25 100644 --- a/builtin/merge.c +++ b/builtin/merge.c @@ -698,8 +698,10 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common, if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET, SKIP_IF_UNCHANGED, 0, NULL, NULL, - NULL) < 0) - return error(_("Unable to write index.")); + NULL) < 0) { + error(_("Unable to write index.")); + return 2; + } if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree") || !strcmp(strategy, "ort")) { diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh index e5ff073099a..f03709ea4be 100755 --- a/t/t7600-merge.sh +++ b/t/t7600-merge.sh @@ -236,6 +236,16 @@ test_expect_success 'merge c1 with c2' ' verify_parents $c1 $c2 ' +test_expect_success 'merge c1 with c2 when index.lock exists' ' + test_when_finished rm .git/index.lock && + git reset --hard c1 && + touch .git/index.lock && + test_must_fail git merge c2 && + test_path_is_missing .git/MERGE_HEAD && + test_path_is_missing .git/MERGE_MODE && + test_path_is_missing .git/MERGE_MSG +' + test_expect_success 'merge --squash c3 with c7' ' git reset --hard c3 && test_must_fail git merge --squash c7 && base-commit: 19fe900cfce8096b7645ec9611a0b981f6bbd154 -- gitgitgadget