From fd911256c247551382bbb5b9534126b95be14516 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 3 Dec 2021 18:57:43 -0500 Subject: [PATCH] unpack-trees: use traverse_path instead of name The sparse_dir_matches_path() method compares a cache entry that is a sparse directory entry against a 'struct traverse_info *info' and a 'struct name_entry *p' to see if the cache entry has exactly the right name for those other inputs. This method was introduced in 523506d (unpack-trees: unpack sparse directory entries, 2021-07-14), but included a significant mistake. The path comparisons used 'info->name' instead of 'info->traverse_path'. Since 'info->name' only stores a single tree entry name while 'info->traverse_path' stores the full path from root, this method does not work when 'info' is in a subdirectory of a directory. Replacing the right strings and their corresponding lengths make the method work properly. The previous change included a failing test that exposes this issue. That test now passes. The critical detail is that as we go deep into unpack_trees(), the logic for merging a sparse directory entry with a tree entry during 'git checkout' relies on this sparse_dir_matches_path() in order to avoid calling traverse_trees_recursive() during unpack_callback() in this hunk: if (!is_sparse_directory_entry(src[0], names, info) && traverse_trees_recursive(n, dirmask, mask & ~dirmask, names, info) < 0) { return -1; } For deep paths, the short-circuit never occurred and traverse_trees_recursive() was being called incorrectly and that was causing other strange issues. Specifically, the error message from the now-passing test previously included this: error: Your local changes to the following files would be overwritten by checkout: deep/deeper1/deepest2/a deep/deeper1/deepest3/a Please commit your changes or stash them before you switch branches. Aborting These messages occurred because the 'current' cache entry in twoway_merge() was showing as NULL because the index did not contain entries for the paths contained within the sparse directory entries. We instead had 'oldtree' given as the entry at HEAD and 'newtree' as the entry in the target tree. This led to reject_merge() listing these paths. Now that sparse_dir_matches_path() works the same for deep paths as it does for shallow depths, the rest of the logic kicks in to properly handle modifying the sparse directory entries as designed. Reported-by: Gustave Granroth Reported-by: Mike Marcelais Signed-off-by: Derrick Stolee --- t/t1092-sparse-checkout-compatibility.sh | 2 +- unpack-trees.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index b0fc390ec85311..f7358001937719 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -308,7 +308,7 @@ test_expect_success 'add, commit, checkout' ' test_all_match git checkout - ' -test_expect_failure 'deep changes during checkout' ' +test_expect_success 'deep changes during checkout' ' init_repos && test_sparse_match git sparse-checkout set deep/deeper1/deepest && diff --git a/unpack-trees.c b/unpack-trees.c index 7229a4a820de5c..478c83c64766d9 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -1270,11 +1270,11 @@ static int sparse_dir_matches_path(const struct cache_entry *ce, assert(S_ISSPARSEDIR(ce->ce_mode)); assert(ce->name[ce->ce_namelen - 1] == '/'); - if (info->namelen) - return ce->ce_namelen == info->namelen + p->pathlen + 2 && - ce->name[info->namelen] == '/' && - !strncmp(ce->name, info->name, info->namelen) && - !strncmp(ce->name + info->namelen + 1, p->path, p->pathlen); + if (info->pathlen) + return ce->ce_namelen == info->pathlen + p->pathlen + 1 && + ce->name[info->pathlen - 1] == '/' && + !strncmp(ce->name, info->traverse_path, info->pathlen) && + !strncmp(ce->name + info->pathlen, p->path, p->pathlen); return ce->ce_namelen == p->pathlen + 1 && !strncmp(ce->name, p->path, p->pathlen); }