From f45f88b2e483649cd063a7dc7826c03025683e56 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?SZEDER=20G=C3=A1bor?= Date: Mon, 21 Oct 2019 18:00:43 +0200 Subject: path.c: don't call the match function without value in trie_find() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 'logs/refs' is not a working tree-specific path, but since commit b9317d55a3 (Make sure refs/rewritten/ is per-worktree, 2019-03-07) 'git rev-parse --git-path' has been returning a bogus path if a trailing '/' is present: $ git -C WT/ rev-parse --git-path logs/refs --git-path logs/refs/ /home/szeder/src/git/.git/logs/refs /home/szeder/src/git/.git/worktrees/WT/logs/refs/ We use a trie data structure to efficiently decide whether a path belongs to the common dir or is working tree-specific. As it happens b9317d55a3 triggered a bug that is as old as the trie implementation itself, added in 4e09cf2acf (path: optimize common dir checking, 2015-08-31). - According to the comment describing trie_find(), it should only call the given match function 'fn' for a "/-or-\0-terminated prefix of the key for which the trie contains a value". This is not true: there are three places where trie_find() calls the match function, but one of them is missing the check for value's existence. - b9317d55a3 added two new keys to the trie: 'logs/refs/rewritten' and 'logs/refs/worktree', next to the already existing 'logs/refs/bisect'. This resulted in a trie node with the path 'logs/refs/', which didn't exist before, and which doesn't have a value attached. A query for 'logs/refs/' finds this node and then hits that one callsite of the match function which doesn't check for the value's existence, and thus invokes the match function with NULL as value. - When the match function check_common() is invoked with a NULL value, it returns 0, which indicates that the queried path doesn't belong to the common directory, ultimately resulting the bogus path shown above. Add the missing condition to trie_find() so it will never invoke the match function with a non-existing value. check_common() will then no longer have to check that it got a non-NULL value, so remove that condition. I believe that there are no other paths that could cause similar bogus output. AFAICT the only other key resulting in the match function being called with a NULL value is 'co' (because of the keys 'common' and 'config'). However, as they are not in a directory that belongs to the common directory the resulting working tree-specific path is expected. Signed-off-by: SZEDER Gábor Signed-off-by: Junio C Hamano --- t/t0060-path-utils.sh | 2 ++ 1 file changed, 2 insertions(+) (limited to 't') diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh index c7b53e494b..501e1a288d 100755 --- a/t/t0060-path-utils.sh +++ b/t/t0060-path-utils.sh @@ -288,6 +288,8 @@ test_git_path GIT_COMMON_DIR=bar index .git/index test_git_path GIT_COMMON_DIR=bar HEAD .git/HEAD test_git_path GIT_COMMON_DIR=bar logs/HEAD .git/logs/HEAD test_git_path GIT_COMMON_DIR=bar logs/refs/bisect/foo .git/logs/refs/bisect/foo +test_git_path GIT_COMMON_DIR=bar logs/refs bar/logs/refs +test_git_path GIT_COMMON_DIR=bar logs/refs/ bar/logs/refs/ test_git_path GIT_COMMON_DIR=bar logs/refs/bisec/foo bar/logs/refs/bisec/foo test_git_path GIT_COMMON_DIR=bar logs/refs/bisec bar/logs/refs/bisec test_git_path GIT_COMMON_DIR=bar logs/refs/bisectfoo bar/logs/refs/bisectfoo -- cgit v1.2.3