From: SZEDER Gábor Date: Mon, 21 Oct 2019 16:00:43 +0000 (+0200) Subject: path.c: don't call the match function without value in trie_find() X-Git-Tag: v2.25.0-rc0~141^2 X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fgit.git;a=commitdiff_plain;h=f45f88b2e483649cd063a7dc7826c03025683e56 path.c: don't call the match function without value in trie_find() '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 --- diff --git a/path.c b/path.c index 81e9bfe7a9..4b69360c71 100644 --- a/path.c +++ b/path.c @@ -299,9 +299,13 @@ static int trie_find(struct trie *root, const char *key, match_fn fn, /* Matched the entire compressed section */ key += i; - if (!*key) + if (!*key) { /* End of key */ - return fn(key, root->value, baton); + if (root->value) + return fn(key, root->value, baton); + else + return -1; + } /* Partial path normalization: skip consecutive slashes */ while (key[0] == '/' && key[1] == '/') @@ -345,9 +349,6 @@ static int check_common(const char *unmatched, void *value, void *baton) { struct common_dir *dir = value; - if (!dir) - return 0; - if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/')) return dir->is_common; 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