@matheusbsbs / matheus-bagliano / commits / 7497039241

read-tree: narrow scope of index expansion for '--prefix'

When 'git read-tree' is provided with a prefix, expand the index only if the prefix is equivalent to a sparse directory or contained within one. If the index is not expanded in these cases, 'ce_in_traverse_path' will indicate that the relevant sparse directory is not in the prefix/traverse path, skipping past it and not unpacking the appropriate tree(s). If the prefix is in-cone, its sparse subdirectories (if any) will be traversed correctly without index expansion. The behavior of 'git read-tree' with prefixes 1) inside of cone, 2) equal to a sparse directory, and 3) inside a sparse directory are all tested as part of the 't/t1092-sparse-checkout-compatibility.sh' test 'read-tree --prefix', ensuring that the sparse index case works the way it did prior to this change as well as matching non-sparse index sparse-checkout. Helped-by: Elijah Newren <newren@gmail.com> Signed-off-by: Victoria Dye <vdye@github.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Victoria Dye committed Mar 1, 2022 at 20:24 UTC 749703924121b9eb2750b4313b2c769113c8b310

3 files changed +46 -3

builtin/read-tree.c

+1 -2

@@ -217,8 +217,7 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)

217 if (opts.merge && !opts.index_only)

218 setup_work_tree();

219

220 - /* TODO: audit sparse index behavior in unpack_trees */

221 - if (opts.skip_sparse_checkout || opts.prefix)

220 + if (opts.skip_sparse_checkout)

221 ensure_full_index(&the_index);

222

223 if (opts.merge) {

t/t1092-sparse-checkout-compatibility.sh

+7 -1

@@ -1417,7 +1417,13 @@ test_expect_success 'sparse index is not expanded: read-tree' '

1417 do

1418 ensure_not_expanded read-tree -mu $MERGE_TREES &&

1419 ensure_not_expanded reset --hard || return 1

1420 - done

1420 + done &&

1421 +

1422 + rm -rf sparse-index/deep/deeper2 &&

1423 + ensure_not_expanded add . &&

1424 + ensure_not_expanded commit -m "test" &&

1425 +

1426 + ensure_not_expanded read-tree --prefix=deep/deeper2 -u deepest

1427 '

1428

1429 test_expect_success 'ls-files' '

unpack-trees.c

+38

@@ -1693,6 +1693,41 @@ static void populate_from_existing_patterns(struct unpack_trees_options *o,

1693 o->pl = pl;

1694 }

1695

1696 +static void update_sparsity_for_prefix(const char *prefix,

1697 + struct index_state *istate)

1698 +{

1699 + int prefix_len = strlen(prefix);

1700 + struct strbuf ce_prefix = STRBUF_INIT;

1701 +

1702 + if (!istate->sparse_index)

1703 + return;

1704 +

1705 + while (prefix_len > 0 && prefix[prefix_len - 1] == '/')

1706 + prefix_len--;

1707 +

1708 + if (prefix_len <= 0)

1709 + BUG("Invalid prefix passed to update_sparsity_for_prefix");

1710 +

1711 + strbuf_grow(&ce_prefix, prefix_len + 1);

1712 + strbuf_add(&ce_prefix, prefix, prefix_len);

1713 + strbuf_addch(&ce_prefix, '/');

1714 +

1715 + /*

1716 + * If the prefix points to a sparse directory or a path inside a sparse

1717 + * directory, the index should be expanded. This is accomplished in one

1718 + * of two ways:

1719 + * - if the prefix is inside a sparse directory, it will be expanded by

1720 + * the 'ensure_full_index(...)' call in 'index_name_pos(...)'.

1721 + * - if the prefix matches an existing sparse directory entry,

1722 + * 'index_name_pos(...)' will return its index position, triggering

1723 + * the 'ensure_full_index(...)' below.

1724 + */

1725 + if (!path_in_cone_mode_sparse_checkout(ce_prefix.buf, istate) &&

1726 + index_name_pos(istate, ce_prefix.buf, ce_prefix.len) >= 0)

1727 + ensure_full_index(istate);

1728 +

1729 + strbuf_release(&ce_prefix);

1730 +}

1731

1732 static int verify_absent(const struct cache_entry *,

1733 enum unpack_trees_error_types,

@@ -1739,6 +1774,9 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options

1774 setup_standard_excludes(o->dir);

1775 }

1776

1777 + if (o->prefix)

1778 + update_sparsity_for_prefix(o->prefix, o->src_index);

1779 +

1780 if (!core_apply_sparse_checkout || !o->update)

1781 o->skip_sparse_checkout = 1;

1782 if (!o->skip_sparse_checkout && !o->pl) {