From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id 378E11F47C for ; Fri, 6 Jan 2023 11:04:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231831AbjAFLED (ORCPT ); Fri, 6 Jan 2023 06:04:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229709AbjAFLD7 (ORCPT ); Fri, 6 Jan 2023 06:03:59 -0500 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7D586E0D2 for ; Fri, 6 Jan 2023 03:03:58 -0800 (PST) Received: (qmail 13991 invoked by uid 109); 6 Jan 2023 11:03:58 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Fri, 06 Jan 2023 11:03:58 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 13264 invoked by uid 111); 6 Jan 2023 11:04:03 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Fri, 06 Jan 2023 06:04:03 -0500 Authentication-Results: peff.net; auth=none Date: Fri, 6 Jan 2023 06:03:57 -0500 From: Jeff King To: Carl Baldwin Cc: Junio C Hamano , Git Mailing List Subject: [PATCH 1/3] diff: use filespec path to set up tempfiles for ext-diff Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org When we're going to run an external diff, we have to make the contents of the pre- and post-images available either by dumping them to a tempfile, or by pointing at a valid file in the worktree. The logic of this is all handled by prepare_temp_file(), and we just pass in the filename and the diff_filespec. But there's a gotcha here. The "filename" we have is a logical filename and not necessarily a path on disk or in the repository. This matters in at least one case: when using "--relative", we may have a name like "foo", even though the file content is found at "subdir/foo". As a result, we look for the wrong path, fail to find "foo", and claim that the file has been deleted (passing "/dev/null" to the external diff, rather than the correct worktree path). We can fix this by passing the pathname from the diff_filespec, which should always be a full repository path (and that's what we want even if reusing a worktree file, since we're always operating from the top-level of the working tree). The breakage seems to go all the way back to cd676a5136 (diff --relative: output paths as relative to the current subdirectory, 2008-02-12). As far as I can tell, before then "name" would always have been the same as the filespec's "path". There are two related cases I looked at that aren't buggy: 1. the only other caller of prepare_temp_file() is run_textconv(). But it always passes the filespec's path field, so it's OK. 2. I wondered if file renames/copies might cause similar confusion. But they don't, because run_external_diff() receives two names in that case: "name" and "other", which correspond to the two sides of the diff. And we did correctly pass "other" when handling the post-image side. Barring the use of "--relative", that would always match "two->path", the path of the second filespec (and the rename destination). So the only bug is just the interaction with external diff drivers and --relative. Reported-by: Carl Baldwin Signed-off-by: Jeff King --- diff.c | 2 +- t/t4045-diff-relative.sh | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/diff.c b/diff.c index 9b14543e6e..59039773a1 100644 --- a/diff.c +++ b/diff.c @@ -4281,7 +4281,7 @@ static void add_external_diff_name(struct repository *r, const char *name, struct diff_filespec *df) { - struct diff_tempfile *temp = prepare_temp_file(r, name, df); + struct diff_tempfile *temp = prepare_temp_file(r, df->path, df); strvec_push(argv, temp->name); strvec_push(argv, temp->hex); strvec_push(argv, temp->mode); diff --git a/t/t4045-diff-relative.sh b/t/t4045-diff-relative.sh index 198dfc9190..9b46c4c1be 100755 --- a/t/t4045-diff-relative.sh +++ b/t/t4045-diff-relative.sh @@ -164,6 +164,35 @@ check_diff_relative_option subdir file2 true --no-relative --relative check_diff_relative_option . file2 false --no-relative --relative=subdir check_diff_relative_option . file2 true --no-relative --relative=subdir +test_expect_success 'external diff with --relative' ' + test_when_finished "git reset --hard" && + echo changed >file1 && + echo changed >subdir/file2 && + + write_script mydiff <<-\EOF && + # hacky pretend diff; the goal here is just to make sure we got + # passed sensible input that we _could_ diff, without relying on + # the specific output of a system diff tool. + echo "diff a/$1 b/$1" && + echo "--- a/$1" && + echo "+++ b/$1" && + echo "@@ -1 +0,0 @@" && + sed "s/^/-/" "$2" && + sed "s/^/+/" "$5" + EOF + + cat >expect <<-\EOF && + diff a/file2 b/file2 + --- a/file2 + +++ b/file2 + @@ -1 +0,0 @@ + -other content + +changed + EOF + GIT_EXTERNAL_DIFF=./mydiff git diff --relative=subdir >actual && + test_cmp expect actual +' + test_expect_success 'setup diff --relative unmerged' ' test_commit zero file0 && test_commit base subdir/file0 && -- 2.39.0.463.g3774f23bc9