restore: avoid sparse index expansion
Teach update_some() to handle sparse directory entries at the tree level rather than expanding the entire sparse index. When iterating a source tree during checkout/restore operations: - If a directory matches a sparse directory entry with the same OID, skip it entirely (no change needed). - If the OID differs and we are in non-overlay mode (e.g., restore --staged), update the sparse directory entry's OID in place. This is semantically correct because non-overlay mode removes paths not in the source tree anyway. - In overlay mode (e.g., checkout <tree> -- .), fall through to recursive descent so individual file entries are preserved correctly. Also switch from index_name_pos() to index_name_pos_sparse() for individual file lookups to avoid triggering ensure_full_index() when the file is already individually tracked in the index. Update the test expectation in t1092 to assert that 'restore --staged' no longer expands the sparse index. Signed-off-by: Derrick Stolee <stolee@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
May 26, 2026 at 20:26 UTC
105aacd072e41c55948d016b46f86f75db2487b3
2 files changed
+63
-10
builtin/checkout.c
+59
-6
@@ -31,6 +31,7 @@
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#include "revision.h"
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#include "sequencer.h"
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#include "setup.h"
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+#include "sparse-index.h"
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#include "strvec.h"
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#include "submodule.h"
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#include "symlinks.h"
@@ -141,15 +142,65 @@ static int post_checkout_hook(struct commit *old_commit, struct commit *new_comm
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return run_hooks_opt(the_repository, "post-checkout", &opt);
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}
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+/*
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+ * Handle a tree object and determine if we need to recurse into the
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+ * tree (READ_TREE_RECURSIVE) or skip it (0).
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+ */
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+static int try_update_sparse_directory(const struct object_id *oid,
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+ struct strbuf *base,
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+ const char *pathname,
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+ int overlay_mode)
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+{
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+ struct strbuf dirpath = STRBUF_INIT;
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+ struct cache_entry *old;
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+ int pos, result = READ_TREE_RECURSIVE;
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+
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+ if (!the_repository->index->sparse_index)
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+ return result;
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+
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+ strbuf_addbuf(&dirpath, base);
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+ strbuf_addstr(&dirpath, pathname);
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+ strbuf_addch(&dirpath, '/');
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+
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+ pos = index_name_pos_sparse(the_repository->index,
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+ dirpath.buf, dirpath.len);
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+ if (pos < 0)
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+ goto cleanup;
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+
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+ old = the_repository->index->cache[pos];
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+ if (!S_ISSPARSEDIR(old->ce_mode))
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+ goto cleanup;
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+
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+ if (oideq(oid, &old->oid)) {
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+ /* Tree content already matches; no need to descend. */
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+ result = 0;
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+ } else if (!overlay_mode) {
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+ /*
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+ * In non-overlay mode (e.g., restore --staged), replace the
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+ * sparse directory OID directly since files not present in
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+ * the source tree should be removed anyway.
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+ */
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+ oidcpy(&old->oid, oid);
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+ old->ce_flags |= CE_UPDATE;
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+ result = 0;
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+ }
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+
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+cleanup:
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+ strbuf_release(&dirpath);
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+ return result;
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+}
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+
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static int update_some(const struct object_id *oid, struct strbuf *base,
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- const char *pathname, unsigned mode, void *context UNUSED)
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+ const char *pathname, unsigned mode, void *context)
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{
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int len;
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struct cache_entry *ce;
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int pos;
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+ int overlay_mode = context ? *((int *)context) : 1;
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if (S_ISDIR(mode))
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- return READ_TREE_RECURSIVE;
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+ return try_update_sparse_directory(oid, base, pathname,
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+ overlay_mode);
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len = base->len + strlen(pathname);
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ce = make_empty_cache_entry(the_repository->index, len);
@@ -165,7 +216,7 @@ static int update_some(const struct object_id *oid, struct strbuf *base,
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* entry in place. Whether it is UPTODATE or not, checkout_entry will
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* do the right thing.
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*/
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- pos = index_name_pos(the_repository->index, ce->name, ce->ce_namelen);
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+ pos = index_name_pos_sparse(the_repository->index, ce->name, ce->ce_namelen);
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if (pos >= 0) {
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struct cache_entry *old = the_repository->index->cache[pos];
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if (ce->ce_mode == old->ce_mode &&
@@ -182,10 +233,11 @@ static int update_some(const struct object_id *oid, struct strbuf *base,
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return 0;
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}
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-static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
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+static int read_tree_some(struct tree *tree, const struct pathspec *pathspec,
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+ int overlay_mode)
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{
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read_tree(the_repository, tree,
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- pathspec, update_some, NULL);
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+ pathspec, update_some, &overlay_mode);
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/* update the index with the given tree's info
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* for all args, expanding wildcards, and exit
@@ -580,7 +632,8 @@ static int checkout_paths(const struct checkout_opts *opts,
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return error(_("index file corrupt"));
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if (opts->source_tree)
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- read_tree_some(opts->source_tree, &opts->pathspec);
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+ read_tree_some(opts->source_tree, &opts->pathspec,
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+ opts->overlay_mode);
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if (opts->merge)
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unmerge_index(the_repository->index, &opts->pathspec, CE_MATCHED);
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t/t1092-sparse-checkout-compatibility.sh
+4
-4
@@ -2608,19 +2608,19 @@ test_expect_success 'restore --staged with wildcards' '
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test_all_match git diff --cached
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'
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-test_expect_success 'sparse-index is expanded: restore --staged' '
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+test_expect_success 'sparse-index is not expanded: restore --staged' '
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init_repos &&
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git -C sparse-index checkout -b restore-staged-exp base &&
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git -C sparse-index reset --soft update-folder1 &&
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- ensure_expanded restore --staged .
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+ ensure_not_expanded restore --staged .
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'
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-test_expect_success 'sparse-index is expanded: restore --source --staged' '
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+test_expect_success 'sparse-index is not expanded: restore --source --staged' '
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init_repos &&
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git -C sparse-index checkout -b restore-source-staged base &&
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- ensure_expanded restore --source update-folder1 --staged .
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+ ensure_not_expanded restore --source update-folder1 --staged .
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'
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test_done