From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jim Hill Subject: [PATCH v4] sha1_file: pass empty buffer to index empty file Date: Sun, 17 May 2015 17:41:45 -0700 Message-ID: <1431909705-29090-1-git-send-email-gjthill@gmail.com> References: Cc: git@vger.kernel.org To: Junio C Hamano X-From: git-owner@vger.kernel.org Mon May 18 02:45:50 2015 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Yu9Bh-0003sD-Sg for gcvg-git-2@plane.gmane.org; Mon, 18 May 2015 02:45:46 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752460AbbERAmV (ORCPT ); Sun, 17 May 2015 20:42:21 -0400 Received: from mail-ig0-f172.google.com ([209.85.213.172]:34327 "EHLO mail-ig0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752297AbbERAlw (ORCPT ); Sun, 17 May 2015 20:41:52 -0400 Received: by igbhj9 with SMTP id hj9so559056igb.1 for ; Sun, 17 May 2015 17:41:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=NPYSS4PqJOfv3vqokH3aNdMR+vOE/wJ5hgHSDo05TBw=; b=dpTsXlAsV3br2MF7670wBERiMiz1q/bl972a5nNg8n/FANzAfti9HGw4f3g8wtTgjj U/axHOUnNeT4lxMlrLzVrH0ObRxfDEPm7mQoLXf2Swbyuh2us1iL7Sc25rFAl4LKOITt 9ynLSU5ebKpp0gx9BMDx71VWbqIOrj0gHSDr59eDDmJNeItkUaWAqGUdFaaS4LBoJX/d LnEWwLSFNqAbR8rVJxr64evwJUCdkaLQMVHgYGmChfJGlG4UQGRxHQtdKuMRQnSnx1bC WchbysilxPCye2p9JXMSKp95xFcnLO1/4EUOpMap3yz0VZ8BRObZWbHVLYiUdHDayFL3 EEpg== X-Received: by 10.50.114.70 with SMTP id je6mr11120146igb.43.1431909711291; Sun, 17 May 2015 17:41:51 -0700 (PDT) Received: from gadabout.domain.actdsltmp (pool-71-119-14-52.lsanca.dsl-w.verizon.net. [71.119.14.52]) by mx.google.com with ESMTPSA id d15sm4508100igo.8.2015.05.17.17.41.49 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 17 May 2015 17:41:50 -0700 (PDT) X-Mailer: git-send-email 2.4.1.4.g08cda19 In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: `git add` of an empty file with a filter pops complaints from `copy_fd` about a bad file descriptor. This traces back to these lines in sha1_file.c:index_core: if (!size) { ret = index_mem(sha1, NULL, size, type, path, flags); The problem here is that content to be added to the index can be supplied from an fd, or from a memory buffer, or from a pathname. This call is supplying a NULL buffer pointer and a zero size. Downstream logic takes the complete absence of a buffer to mean the data is to be found elsewhere -- for instance, these, from convert.c: if (params->src) { write_err = (write_in_full(child_process.in, params->src, params->size) < 0); } else { write_err = copy_fd(params->fd, child_process.in); } ~If there's a buffer, write from that, otherwise the data must be coming from an open fd.~ Perfectly reasonable logic in a routine that's going to write from either a buffer or an fd. So change `index_core` to supply an empty buffer when indexing an empty file. There's a patch out there that instead changes the logic quoted above to take a `-1` fd to mean "use the buffer", but it seems to me that the distinction between a missing buffer and an empty one carries intrinsic semantics, where the logic change is adapting the code to handle incorrect arguments. Signed-off-by: Jim Hill --- Okay, that's it: I'm officially laughably rusty, 'cause I'm laughing. This applies your fix, _thank you_ for the caution. I get it: `true` can have already exited by the time the write hits. sha1_file.c | 2 +- t/t0021-conversion.sh | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/sha1_file.c b/sha1_file.c index f860d67..61e2735 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -3186,7 +3186,7 @@ static int index_core(unsigned char *sha1, int fd, size_t size, int ret; if (!size) { - ret = index_mem(sha1, NULL, size, type, path, flags); + ret = index_mem(sha1, "", size, type, path, flags); } else if (size <= SMALL_FILE_SIZE) { char *buf = xmalloc(size); if (size == read_in_full(fd, buf, size)) diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh index ca7d2a6..eee4761 100755 --- a/t/t0021-conversion.sh +++ b/t/t0021-conversion.sh @@ -216,4 +216,30 @@ test_expect_success EXPENSIVE 'filter large file' ' ! test -s err ' +test_expect_success "filter: clean empty file" ' + git config filter.in-repo-header.clean "echo cleaned && cat" && + git config filter.in-repo-header.smudge "sed 1d" && + + echo "empty-in-worktree filter=in-repo-header" >>.gitattributes && + >empty-in-worktree && + + echo cleaned >expected && + git add empty-in-worktree && + git show :empty-in-worktree >actual && + test_cmp expected actual +' + +test_expect_success "filter: smudge empty file" ' + git config filter.empty-in-repo.clean "cat >/dev/null" && + git config filter.empty-in-repo.smudge "echo smudged && cat" && + + echo "empty-in-repo filter=empty-in-repo" >>.gitattributes && + echo dead data walking >empty-in-repo && + git add empty-in-repo && + + echo smudged >expected && + git checkout-index --prefix=filtered- empty-in-repo && + test_cmp expected filtered-empty-in-repo +' + test_done -- 2.4.1.4.g08cda19