From: Elijah Newren <newren@gmail.com>
To: git@vger.kernel.org
Cc: Victoria Dye <vdye@github.com>, Derrick Stolee <stolee@gmail.com>,
Lessley Dennington <lessleydennington@gmail.com>,
Elijah Newren <newren@gmail.com>
Subject: [RFC PATCH 2/5] unpack-trees: fix accidental loss of user changes
Date: Sat, 8 Jan 2022 20:57:29 -0800 [thread overview]
Message-ID: <20220109045732.2497526-3-newren@gmail.com> (raw)
In-Reply-To: <20220109045732.2497526-1-newren@gmail.com>
For sparse-checkouts, we don't want unpack-trees to error out on files
that are missing from the worktree, so there has traditionally been
logic to make it skip the verify_uptodate() check for these.
Unfortunately, it was skipping the verify_uptodate() check for files
that were expected to *become* SKIP_WORKTREE. For files that were not
already SKIP_WORKTREE, that can cause us to later delete the file in
apply_sparse_checkout(). Only skip the check for files that were
already SKIP_WORKTREE as well to avoid lightly discarding important
changes users may have made to files.
Note 1: unpack-trees.c is already a bit complex, and the logic around
CE_SKIP_WORKTREE and CE_NEW_SKIP_WORKTREE in that file are no exception.
I also tried just replacing CE_NEW_SKIP_WORKTREE with CE_SKIP_WORKTREE
in the verify_uptodate() check instead of checking for both flags, and
found that it also fixed this bug and passed all the tests. I also
attempted to devise a few testcases that might trip either variant of my
fix and was unable to find any problems. It may be that just checking
CE_SKIP_WORKTREE is a better fix, but I'm not sure. I thought it
was a bit safer to strictly reduce the number of cases where we skip the
up-to-date check rather than just toggling which kind of cases skip it,
and thus went with the current variant of the fix.
Note 2: I also wondered if verify_absent() might have a similar bug, but
despite my attempts to try to devise a testcase that would trigger such
a thing, I couldn't find any problematic testcases. Thus, this patch
makes no attempt to apply similar changes to verify_absent() and
verify_absent_if_directory().
Signed-off-by: Elijah Newren <newren@gmail.com>
---
t/t1011-read-tree-sparse-checkout.sh | 2 +-
unpack-trees.c | 4 +++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/t/t1011-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
index 1b2395b8a8..4ed0885bf2 100755
--- a/t/t1011-read-tree-sparse-checkout.sh
+++ b/t/t1011-read-tree-sparse-checkout.sh
@@ -197,7 +197,7 @@ test_expect_success 'read-tree will not throw away dirty changes, non-sparse' '
grep -q dirty init.t
'
-test_expect_failure 'read-tree will not throw away dirty changes, sparse' '
+test_expect_success 'read-tree will not throw away dirty changes, sparse' '
echo "/*" >.git/info/sparse-checkout &&
read_tree_u_must_succeed -m -u HEAD &&
diff --git a/unpack-trees.c b/unpack-trees.c
index 98e2f2e0e6..6d9d89c662 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -2059,7 +2059,9 @@ static int verify_uptodate_1(const struct cache_entry *ce,
int verify_uptodate(const struct cache_entry *ce,
struct unpack_trees_options *o)
{
- if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
+ if (!o->skip_sparse_checkout &&
+ (ce->ce_flags & CE_SKIP_WORKTREE) &&
+ (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
return 0;
return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
}
--
2.34.1.442.ge63c19bdd2.dirty
next prev parent reply other threads:[~2022-01-09 4:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-09 4:57 [RFC PATCH 0/5] Remove the present-despite-SKIP_WORKTREE class of bugs Elijah Newren
2022-01-09 4:57 ` [RFC PATCH 1/5] t1011: add testcase demonstrating accidental loss of user modifications Elijah Newren
2022-01-09 4:57 ` Elijah Newren [this message]
2022-01-09 4:57 ` [RFC PATCH 3/5] repo_read_index: ensure SKIP_WORKTREE means skip worktree Elijah Newren
2022-01-10 20:38 ` Victoria Dye
2022-01-11 19:27 ` Elijah Newren
2022-01-11 23:09 ` Victoria Dye
2022-01-09 4:57 ` [RFC PATCH 4/5] Update documentation related to sparsity and the skip-worktree bit Elijah Newren
2022-01-09 4:57 ` [RFC PATCH 5/5] Accelerate ensure_skip_worktree_means_skip_worktree by caching Elijah Newren
2022-01-11 18:30 ` Victoria Dye
2022-01-11 22:04 ` Elijah Newren
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